test(node): cover the sweep's boot wiring and prove an interrupted push never reaches the upload

Two claims from earlier commits were argued rather than executed. Both are now observed. The legacy-CID sweep's spawn sat inline in main() where no test could reach it, so the batch size, the inter-batch delay, the detachment and the shutdown select were all reasoned. The block moves verbatim into `spawn_legacy_cid_sweep`, which a test calls directly. It seeds rows whose keys are already canonical, so the cost gate skips each and the persisted cursor reads out walk progress cleanly, then asserts the cursor stops at the configured batch boundary, the call returns without blocking, the task is still alive inside its delay, and shutdown ends it. Never spawning, reading the batch or delay from the wrong knob, or removing the shutdown branch each turns it red. What remains reasoned is the single call line inside main(), down from a twenty-six line block. The claim that a disconnect-interrupted push never uploads to Tigris was structural: the tests build the store with no Tigris client, so a counter inside the client arm could never move and would have proved nothing. The counter now sits at the upload decision, before the client is consulted, and the disconnect test asserts zero while the success test asserts exactly one. That positive control is what makes the zero meaningful, and it is itself load-bearing: releasing the success path with failure semantics drops it to zero, and adding a Drop impl that uploads raises the disconnect count to one. The counter observes reaching the upload site, not an S3 request. TigrisClient wraps a concrete SDK client with no injectable endpoint, and plumbing one through would be out of proportion to the risk here.
fix(node): shed 503 from the issue and PR write paths when the lock pool is exhausted
2026-11-08 17:55:53 -10:00 · 2026-07-27 21:44:31 -05:00 · 2026-07-27 21:14:55 -05:00 · 2026-07-27 18:29:01 -05:00 · 2026-07-27 17:47:56 -05:00 · 2026-07-27 15:53:26 -05:00
57 changed files with 23809 additions and 1053 deletions
@@ -21,6 +21,23 @@ GITLAWB_REPOS_DIR=/data/repos
 # When using the bundled docker-compose, this is wired automatically.
 DATABASE_URL=postgresql://gitlawb:changeme@localhost:5432/gitlawb

+# ── Database pool & startup resilience ────────────────────────────────────
+# Maximum connections in the PostgreSQL pool. A cap, not a floor —
+# connections open lazily. Size against the DB server's max_connections,
+# remembering admin tooling opens its own pool.
+GITLAWB_DB_MAX_CONNECTIONS=20
+# Seconds a request waits for a pool connection before failing with 503.
+GITLAWB_DB_ACQUIRE_TIMEOUT_SECS=5
+# Upper bound on each startup connect+migrate attempt, in seconds. Keep it
+# generous enough for a peer instance to finish migrating (the migration
+# advisory lock is held across a deploy); on expiry the attempt is retried.
+GITLAWB_DB_CONNECT_TIMEOUT_SECS=60
+# Startup retry backoff while the database is unavailable: first delay and
+# ceiling, in seconds. The node stays up serving 503s (with a truthful
+# /ready) instead of crash-looping.
+GITLAWB_DB_RETRY_INITIAL_SECS=5
+GITLAWB_DB_RETRY_MAX_SECS=60
+
 # ── IPFS pinning (Pinata) ─────────────────────────────────────────────────
 # Get a JWT at https://app.pinata.cloud/developers/api-keys
 GITLAWB_PINATA_JWT=
@@ -90,11 +107,94 @@ GITLAWB_PUBLIC_READ=true
 # Maximum git smart-HTTP pack request size, in bytes.
 GITLAWB_MAX_PACK_BYTES=2147483648

+# Max seconds a served git upload-pack / receive-pack (clone / push) may run
+# before it is aborted with a 504. Bounds a hung git that would otherwise pin a
+# worker and, on push, the repo write lock. Also bounds both info/refs
+# advertisements, the withheld-blob pack build, and the push-side candidate
+# discovery (rev-list / cat-file), all reaped via process-group teardown (#174).
+# Default 600.
+GITLAWB_GIT_SERVICE_TIMEOUT_SECS=600
+
+# Max seconds the storage-ACQUISITION phase of a served git op may run before the
+# request is shed with a 503, separate from the git-run timeout above. A
+# concurrency permit is taken before this phase and GITLAWB_GIT_SERVICE_TIMEOUT_SECS
+# only starts once git spawns, so without this a stalled backend (a hung Tigris
+# HEAD/GET, or a hung pg advisory-lock iteration on push) pins the permit and drains
+# the pool until every later request 503s. On expiry the permit is released
+# (fail-closed). Kept separate because acquisition and git execution are distinct
+# cost centers. Must be positive; set very large to effectively disable. Default 30.
+GITLAWB_GIT_ACQUIRE_TIMEOUT_SECS=30
+
+# Max concurrent git READ ops (upload-pack + the upload-pack info/refs
+# advertisement) served at once, a global pool separate from the push pool below.
+# The anon receive-pack info/refs advertisement has its OWN pool (see below), not
+# this one. Over-cap sheds a clean 503 + Retry-After. Anonymous reads draw from
+# here, so pair it with GITLAWB_MAX_CONCURRENT_READS_PER_CALLER (below) so one
+# caller cannot monopolize the pool. Default 128.
+GITLAWB_MAX_CONCURRENT_GIT_OPS=128
+
+# Max concurrent git-receive-pack (push) POST operations, in a pool separate from
+# the read pool (GITLAWB_MAX_CONCURRENT_GIT_OPS) so anonymous reads cannot shed an
+# authenticated push at admission. The anon receive-pack info/refs advertisement
+# runs in a SEPARATE pool of the same size (disjoint from this one), so an
+# advertisement flood cannot shed a push either. Over-cap sheds a 503 +
+# Retry-After. Default 32.
+GITLAWB_MAX_CONCURRENT_GIT_PUSHES=32
+
+# Max concurrent read ops (upload-pack + the upload-pack info/refs advertisement)
+# a single caller may hold, so one caller cannot monopolize the read pool. Keyed
+# on the resolved SOURCE IP, never the DID: a signature does not move a caller off
+# this cap. The source-IP key is only as granular as GITLAWB_TRUSTED_PROXY below:
+# left unset, a node behind an edge/NAT keys all callers on the edge IP and this
+# collapses to one global cap. Set GITLAWB_TRUSTED_PROXY for per-client keying; a
+# high-fanout caller (CI behind one NAT) then needs the operator to raise this.
+# Default 16.
+GITLAWB_MAX_CONCURRENT_READS_PER_CALLER=16
+
 # ── Push rate limiting (git-receive-pack flood brake) ─────────────────────
 # Max receive-pack requests (info/refs advertisement + push POST) per client
 # IP per hour. 0 disables. Default 600.
 GITLAWB_PUSH_RATE_LIMIT=600

+# ── /ipfs/{cid} visibility-walk admission (#174) ──────────────────────────
+# GET /ipfs/{cid} runs a per-repo full-history git walk in a blocking thread to
+# decide whether the caller may read a path-scoped blob. It is publicly reachable,
+# so it is bounded to keep a permissionless caller from fanning out unbounded
+# concurrent walks and exhausting blocking-pool threads + PIDs.
+# Max concurrent /ipfs walks across all callers (a pool of its own, disjoint from
+# the served-git pools). Over-cap sheds a 503. Default 32.
+GITLAWB_MAX_CONCURRENT_IPFS_WALKS=32
+# Max concurrent /ipfs walks a single SOURCE IP may hold (keyed like the git
+# per-caller caps via GITLAWB_TRUSTED_PROXY; reject-before-insert bounded map).
+# Default 4.
+GITLAWB_IPFS_WALK_PER_SOURCE=4
+# Max legacy (NULL-provenance) repos probed per single /ipfs request, bounding the
+# scan-fallback fan-out (git cat-file per candidate repo) for an anonymous caller. A
+# truncated scan sheds a retryable 503, never a false 404. Default 256.
+GITLAWB_IPFS_MAX_REPOS_WALKED=256
+# Max /ipfs/{cid} requests per client IP per hour (route flood brake, distinct
+# from the concurrency caps above). 0 disables. Default 600.
+GITLAWB_IPFS_RATE_LIMIT=600
+
+# ── Creation rate limiting (repo/agent/issue/PR flood brake) ──────────────
+# Max creation requests (POST /api/v1/repos, /api/register, fork, issues,
+# pulls) per client IP per hour, in addition to the per-DID limit. The per-DID
+# limit alone is bypassed by a did:key farm (one throwaway identity per repo),
+# which is how spam-repo floods slip past it and the iCaptcha gate; the per-IP
+# brake caps a single-source flood. Uses GITLAWB_TRUSTED_PROXY below to resolve
+# the client IP. 0 disables. Default 120.
+GITLAWB_CREATE_RATE_LIMIT=120
+
+# ── Peer-sync rate limiting (per client IP, uses GITLAWB_TRUSTED_PROXY below) ─
+# /api/v1/peers/announce and /api/v1/sync/notify accept unsigned requests from
+# known peers and run at higher frequency, so a generous bucket. Separate from
+# the trigger bucket so an unsigned notify flood can't drain trigger's quota.
+# 0 disables. Default 600.
+GITLAWB_PEER_WRITE_RATE_LIMIT=600
+# /api/v1/sync/trigger requires a signature and fans out to every peer per call,
+# so it gets a tight bucket. 0 disables. Default 60.
+GITLAWB_SYNC_TRIGGER_RATE_LIMIT=60
+
 # Which forwarded header the edge is trusted to set, used to resolve the real
 # client IP for the push limiter. One of:
 #   (unset) — no trusted proxy: key on the socket peer address, ignore headers.
@@ -116,10 +116,14 @@ jobs:
        include:
          - target: x86_64-unknown-linux-musl
            os: ubuntu-latest
+          # Native arm64 runner: cross-compiling this target with the glibc
+          # toolchain broke aws-lc-sys, and native lets the smoke test run.
          - target: aarch64-unknown-linux-musl
-            os: ubuntu-latest
+            os: ubuntu-24.04-arm
+          # macos-13 (the last plain Intel image) is retired and queues forever;
+          # macos-15-intel is GitHub's supported Intel label.
          - target: x86_64-apple-darwin
-            os: macos-13
+            os: macos-15-intel
          - target: aarch64-apple-darwin
            os: macos-14
          - target: x86_64-pc-windows-msvc
@@ -137,16 +141,13 @@ jobs:
          toolchain: stable
          targets: ${{ matrix.target }}

+      # Both musl targets build natively on a matching-arch runner, so the stock
+      # musl-gcc wrapper is all that's needed (no cross toolchain).
      - name: Install musl tools (linux)
        if: contains(matrix.target, 'linux-musl')
        run: |
          sudo apt-get update
          sudo apt-get install -y musl-tools
-          if [ "${{ matrix.target }}" = "aarch64-unknown-linux-musl" ]; then
-            sudo apt-get install -y gcc-aarch64-linux-gnu
-            echo "CARGO_TARGET_AARCH64_UNKNOWN_LINUX_MUSL_LINKER=aarch64-linux-gnu-gcc" >> "$GITHUB_ENV"
-            echo "CC_aarch64_unknown_linux_musl=aarch64-linux-gnu-gcc" >> "$GITHUB_ENV"
-          fi

      - name: Cache cargo
        uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
@@ -171,10 +172,9 @@ jobs:
          cargo build --release --target ${{ matrix.target }} $args

      # Run each packaged binary's --version so a broken release artifact fails the
-      # build instead of shipping. Skipped for cross-compiled targets that can't run
-      # on the host runner (aarch64 linux on an x86_64 runner).
+      # build instead of shipping. Every target builds on a matching-arch runner,
+      # so all of them can execute here.
      - name: Smoke test binaries
-        if: ${{ matrix.target != 'aarch64-unknown-linux-musl' }}
        shell: bash
        run: |
          set -euo pipefail
@@ -1,3 +1,3 @@
 {
-  ".": "0.5.0"
+  ".": "0.5.1"
 }
@@ -1,5 +1,19 @@
 # Changelog

+## [0.5.1](https://github.com/Gitlawb/node/compare/v0.5.0...v0.5.1) (2026-07-10)
+
+
+### Bug Fixes
+
+* **bounties:** add tests for claim_bounty repo-read gate ([#160](https://github.com/Gitlawb/node/issues/160)) ([#169](https://github.com/Gitlawb/node/issues/169)) ([6bafaa6](https://github.com/Gitlawb/node/commit/6bafaa6dc5f05c0dcd61c708397afddbcf8c2e3f))
+* **deps:** bump crossbeam-epoch to 0.9.20 for RUSTSEC-2026-0204 ([#162](https://github.com/Gitlawb/node/issues/162)) ([#163](https://github.com/Gitlawb/node/issues/163)) ([67ad2b8](https://github.com/Gitlawb/node/commit/67ad2b876c8d9a336219d1016968de7a88fc4e75))
+* **node,git:** bound a hung served git with a total-duration timeout ([#62](https://github.com/Gitlawb/node/issues/62)) ([#165](https://github.com/Gitlawb/node/issues/165)) ([cd67718](https://github.com/Gitlawb/node/commit/cd67718f49ec38726a40f6bcf36f539ccdb42969))
+* **node:** bound list_ref_certificates with LIMIT and add upsert to prevent unbounded growth ([#147](https://github.com/Gitlawb/node/issues/147)) ([#149](https://github.com/Gitlawb/node/issues/149)) ([6b5e5bc](https://github.com/Gitlawb/node/commit/6b5e5bc7aee00a2d03295d3620df1ee4d8c024a2))
+* **node:** gate POST /api/v1/sync/trigger and rate-limit the peer-sync routes ([#82](https://github.com/Gitlawb/node/issues/82)) ([#161](https://github.com/Gitlawb/node/issues/161)) ([d00d89a](https://github.com/Gitlawb/node/commit/d00d89ae5be992d1f63e95b714ae1bd3735e8457))
+* **node:** rate-limit repo/agent creation per client IP to stop DID-farm spam floods ([#180](https://github.com/Gitlawb/node/issues/180)) ([dfcaa22](https://github.com/Gitlawb/node/commit/dfcaa22b23ec91be4c75926956aa994ca89de8d5))
+* **release:** build aarch64-musl natively on arm64 runners, replace retired macos-13 ([#155](https://github.com/Gitlawb/node/issues/155)) ([6cff528](https://github.com/Gitlawb/node/commit/6cff5286b436fdee44ad881999e2a5f4bdba18f9))
+* **visibility:** gate repo-scoped read surfaces on visibility ([#120](https://github.com/Gitlawb/node/issues/120)) ([#157](https://github.com/Gitlawb/node/issues/157)) ([26bc3f6](https://github.com/Gitlawb/node/commit/26bc3f69870aa77e43c0d92115a5aa59555b7d88))
+
 ## [0.5.0](https://github.com/Gitlawb/node/compare/v0.4.0...v0.5.0) (2026-07-05)


@@ -2293,9 +2293,9 @@ dependencies = [

 [[package]]
 name = "crossbeam-epoch"
-version = "0.9.18"
+version = "0.9.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5b82ac4a3c2ca9c3460964f020e1402edd5753411d7737aa39c3714ad1b5420e"
+checksum = "2d6914041f254d6e9176c01941b21115dcfb7089e55135a35411081bd106ef3f"
 dependencies = [
 "crossbeam-utils",
 ]
@@ -3300,7 +3300,7 @@ dependencies = [

 [[package]]
 name = "git-remote-gitlawb"
-version = "0.4.0"
+version = "0.5.1"
 dependencies = [
 "anyhow",
 "gitlawb-core",
@@ -3312,7 +3312,7 @@ dependencies = [

 [[package]]
 name = "gitlawb-attest"
-version = "0.4.0"
+version = "0.5.1"
 dependencies = [
 "base64",
 "ed25519-dalek",
@@ -3329,7 +3329,7 @@ dependencies = [

 [[package]]
 name = "gitlawb-core"
-version = "0.4.0"
+version = "0.5.1"
 dependencies = [
 "anyhow",
 "base64",
@@ -3356,7 +3356,7 @@ dependencies = [

 [[package]]
 name = "gitlawb-node"
-version = "0.4.0"
+version = "0.5.1"
 dependencies = [
 "alloy",
 "anyhow",
@@ -3412,7 +3412,7 @@ dependencies = [

 [[package]]
 name = "gl"
-version = "0.4.0"
+version = "0.5.1"
 dependencies = [
 "alloy",
 "anyhow",
@@ -3824,6 +3824,7 @@ dependencies = [
 "reqwest",
 "serde",
 "serde_json",
+ "sha2",
 "thiserror 2.0.18",
 "tracing",
 ]
@@ -302,20 +302,21 @@ POST /api/v1/bounties/{id}/...
 POST /{owner}/{repo}/git-receive-pack
 ```

-Peer write routes support staged rollout:
+These peer write routes support staged rollout:

 ```txt
 POST /api/v1/peers/announce
 POST /api/v1/sync/notify
-POST /api/v1/sync/trigger
 ```

-When `GITLAWB_REQUIRE_SIGNED_PEER_WRITES=false`, unsigned legacy peers are accepted, but signed requests are verified when signature headers are present. Once all live peers upgrade, operators can set:
+When `GITLAWB_REQUIRE_SIGNED_PEER_WRITES=false`, unsigned legacy peers are accepted on those two routes, but signed requests are verified when signature headers are present. Once all live peers upgrade, operators can set:

 ```bash
 GITLAWB_REQUIRE_SIGNED_PEER_WRITES=true
 ```

+`POST /api/v1/sync/trigger` is not part of the staged rollout: it always requires a signature in both config modes and returns 401 without one, because each call drives an O(peers) outbound fan-out.
+
 ---

 ## Configuration
@@ -342,12 +343,20 @@ Important node settings:
 | `GITLAWB_REQUIRE_SIGNED_PEER_WRITES` | Require signed peer announce/sync writes. |
 | `GITLAWB_AUTO_SYNC` | Enable automatic sync from known peers. |
 | `GITLAWB_MAX_PACK_BYTES` | Max git pack body size for smart-HTTP routes. |
+| `GITLAWB_GIT_SERVICE_TIMEOUT_SECS` | Max seconds a served git upload-pack, receive-pack, or `info/refs` advertisement may run before it is aborted (504). Default 600. Also bounds the withheld-blob classification walk (on both the upload-pack serve and receive-pack replication paths) and the push-side pin-candidate discovery (`rev-list` / `cat-file`), each reaped via process-group teardown at the deadline. |
+| `GITLAWB_GIT_ACQUIRE_TIMEOUT_SECS` | Max seconds the storage-acquisition phase (Tigris HEAD/GET, push advisory-lock) of a served git op may run before the request is shed with a 503, separate from the git-run timeout. The concurrency permit is released on expiry so a stalled backend cannot pin the pool. Default 30. |
+| `GITLAWB_MAX_CONCURRENT_IPFS_WALKS` | Max concurrent `GET /ipfs/{cid}` visibility walks across all callers (own pool, disjoint from the served-git pools); over-cap sheds 503. Default 32. |
+| `GITLAWB_IPFS_WALK_PER_SOURCE` | Max concurrent `/ipfs` walks a single source IP may hold. Default 4. |
+| `GITLAWB_IPFS_MAX_REPOS_WALKED` | Max legacy (NULL-provenance) repos probed per `/ipfs/{cid}` request, bounding the scan-fallback fan-out. A truncated scan returns a retryable 503, not a false 404. Default 256. |
+| `GITLAWB_IPFS_RATE_LIMIT` | Max `/ipfs/{cid}` requests per client IP per hour (route flood brake). 0 disables. Default 600. |
 | `GITLAWB_TIGRIS_BUCKET` | Optional S3/Tigris shared repo storage bucket. |
 | `GITLAWB_PINATA_JWT` | Optional Pinata/IPFS warm-storage pinning. |
 | `GITLAWB_IRYS_URL` | Optional Irys/Arweave permanent anchoring. |

 Production note: change the default Postgres password before exposing a node publicly.

+Legacy-pin window: releases before the CID-resolver work stored the provider CID (Kubo dag-pb / Pinata) as a pinned object's resolver key. The `/ipfs/{cid}` resolver now recomputes the raw-content CID from the object bytes and refuses to serve a key that does not match, so `GET /api/v1/ipfs/pins` can still advertise an unrepaired legacy CID that 404s. Such a row is repaired opportunistically the next time a push carries the object again (its key is rewritten to the raw CID, the old value kept in `legacy_provider_cid`), but git negotiation omits objects the node already has, so most legacy rows never re-enter a push delta. A deferred one-shot startup sweep, not this opportunistic path, is what fully retires the advertise-then-404 window. Rows whose object bytes are gone stay withheld.
+
 ---

 ## Optional node staking
@@ -1,7 +1,7 @@
 [package]
 name = "git-remote-gitlawb"
 description = "Git remote helper — enables 'git clone gitlawb://did:gitlawb:...'"
-version = "0.5.0" # x-release-please-version
+version = "0.5.1" # x-release-please-version
 edition.workspace = true
 rust-version.workspace = true
 license.workspace = true
@@ -1,7 +1,7 @@
 [package]
 name = "gitlawb-attest"
 description = "External Attestation v1: pluggable provenance attachments for gitlawb ref-update certs"
-version = "0.5.0" # x-release-please-version
+version = "0.5.1" # x-release-please-version
 edition.workspace = true
 rust-version.workspace = true
 license.workspace = true
@@ -1,7 +1,7 @@
 [package]
 name = "gitlawb-core"
 description = "Core cryptographic primitives for the gitlawb network: DIDs, CIDs, UCAN, HTTP Signatures, ref-update certificates"
-version = "0.5.0" # x-release-please-version
+version = "0.5.1" # x-release-please-version
 edition.workspace = true
 rust-version.workspace = true
 license.workspace = true
@@ -64,6 +64,19 @@ impl Cid {
    }
 }

+/// True when `s` parses as a CIDv1 with the raw codec — the exact shape
+/// [`Cid::from_git_object_bytes`] produces and the `/ipfs` resolver looks up.
+/// A legacy provider CID (Kubo dag-pb, Pinata CIDv0) parses to a different
+/// version or codec and returns `false`, marking it an opportunistic-repair
+/// candidate. Decidable from the string alone (no object bytes), so the pin path
+/// can gate the byte-read/recompute cost on it and leave non-legacy rows at the
+/// existing DB-only skip cost. An unparseable string is non-canonical (`false`).
+pub fn is_raw_cidv1(s: &str) -> bool {
+    s.parse::<CidGeneric<64>>()
+        .map(|c| c.version() == cid::Version::V1 && c.codec() == RAW)
+        .unwrap_or(false)
+}
+
 impl fmt::Display for Cid {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{}", self.0)
@@ -177,6 +190,38 @@ mod tests {
        assert!(result.is_err());
    }

+    #[test]
+    fn is_raw_cidv1_classifies_codec_from_string() {
+        // The canonical resolver key: CIDv1 + raw codec → not a repair candidate.
+        let raw = Cid::from_git_object_bytes(b"blob 5\0hello");
+        assert!(
+            is_raw_cidv1(raw.as_str()),
+            "from_git_object_bytes output is CIDv1/raw"
+        );
+
+        // A CIDv0 (Pinata dag-pb legacy shape) → repair candidate.
+        assert!(
+            !is_raw_cidv1("QmYwAPJzv5CZsnA625s3Xf2nemtYgPpHdWEz79ojWnPbdG"),
+            "a CIDv0 dag-pb value is a legacy-repair candidate"
+        );
+
+        // A CIDv1 with the dag-pb codec (the Kubo above-block-size root) over the
+        // same multihash → still a repair candidate (codec, not just version).
+        let parsed = raw.as_str().parse::<CidGeneric<64>>().unwrap();
+        const DAG_PB: u64 = 0x70;
+        let dagpb = CidGeneric::<64>::new_v1(DAG_PB, *parsed.hash()).to_string();
+        assert!(
+            !is_raw_cidv1(&dagpb),
+            "a CIDv1 dag-pb value is a legacy-repair candidate"
+        );
+
+        // Garbage is non-canonical.
+        assert!(
+            !is_raw_cidv1("not-a-cid"),
+            "an unparseable string is non-canonical"
+        );
+    }
+
    #[test]
    fn sha256_hex_of_empty_input_is_well_known() {
        // SHA-256("") is a fixed constant; verifies the hasher is wired correctly.
@@ -1,7 +1,7 @@
 [package]
 name = "gitlawb-node"
 description = "The gitlawb node daemon — git hosting over HTTP with DID auth"
-version = "0.5.0" # x-release-please-version
+version = "0.5.1" # x-release-please-version
 edition.workspace = true
 rust-version.workspace = true
 license.workspace = true
@@ -110,19 +110,28 @@ pub async fn create_bounty(
    Ok((StatusCode::CREATED, Json(bounty)))
 }

+const MAX_BOUNTY_LIMIT: i64 = 200;
+
 /// GET /api/v1/repos/{owner}/{repo}/bounties
 pub async fn list_repo_bounties(
    State(state): State<AppState>,
    Path((owner, repo)): Path<(String, String)>,
    Query(q): Query<ListBountiesQuery>,
+    auth: Option<Extension<AuthenticatedDid>>,
 ) -> Result<Json<serde_json::Value>> {
+    let caller = auth.as_ref().map(|e| e.0 .0.as_str());
+    crate::api::authorize_repo_read(&state, &owner, &repo, caller, "/").await?;
+
+    let limit = q.limit.unwrap_or(50).clamp(1, MAX_BOUNTY_LIMIT);
    let bounties = state
        .db
        .list_bounties(
            Some(&owner),
            Some(&repo),
            q.status.as_deref(),
-            q.limit.unwrap_or(50),
+            limit,
+            None,
+            None,
        )
        .await?;

@@ -133,25 +142,92 @@ pub async fn list_repo_bounties(
 pub async fn list_all_bounties(
    State(state): State<AppState>,
    Query(q): Query<ListBountiesQuery>,
+    auth: Option<Extension<AuthenticatedDid>>,
 ) -> Result<Json<serde_json::Value>> {
-    let bounties = state
-        .db
-        .list_bounties(None, None, q.status.as_deref(), q.limit.unwrap_or(50))
-        .await?;
+    let raw_limit = q.limit.unwrap_or(50);
+    let limit = raw_limit.clamp(1, MAX_BOUNTY_LIMIT);

-    Ok(Json(serde_json::json!({ "bounties": bounties })))
+    let caller = auth.as_ref().map(|e| e.0 .0.as_str());
+    let mut memo = std::collections::HashMap::new();
+    let mut allowed: Vec<BountyRecord> = Vec::new();
+    let page_size = (limit * 5).clamp(1, 200);
+    let max_scanned = 10_000i64;
+    let mut total_scanned: i64 = 0;
+    let mut cursor: Option<(String, String)> = None;
+
+    while (allowed.len() as i64) < limit {
+        let after = cursor.as_ref().map(|(ts, id)| (ts.as_str(), id.as_str()));
+        let bounties = state
+            .db
+            .list_bounties(
+                None,
+                None,
+                q.status.as_deref(),
+                page_size,
+                after.map(|(ts, _)| ts),
+                after.map(|(_, id)| id),
+            )
+            .await?;
+        if bounties.is_empty() {
+            break;
+        }
+
+        total_scanned += bounties.len() as i64;
+        if total_scanned > max_scanned {
+            return Err(AppError::Incomplete(
+                "too many rows scanned; refine your filters".into(),
+            ));
+        }
+
+        let last = bounties.last().unwrap();
+        for b in &bounties {
+            if (allowed.len() as i64) >= limit {
+                break;
+            }
+            let key = format!("{}/{}", b.repo_owner, b.repo_name);
+            let admitted = if let Some(&result) = memo.get(&key) {
+                result
+            } else {
+                let result = crate::api::authorize_repo_read(
+                    &state,
+                    &b.repo_owner,
+                    &b.repo_name,
+                    caller,
+                    "/",
+                )
+                .await
+                .is_ok();
+                memo.insert(key, result);
+                result
+            };
+            if admitted {
+                allowed.push(b.clone());
+            }
+        }
+        cursor = Some((last.created_at.clone(), last.id.clone()));
+    }
+
+    Ok(Json(serde_json::json!({ "bounties": allowed })))
 }

 /// GET /api/v1/bounties/{id}
 pub async fn get_bounty(
    State(state): State<AppState>,
    Path(id): Path<String>,
+    auth: Option<Extension<AuthenticatedDid>>,
 ) -> Result<Json<BountyRecord>> {
-    let bounty = state
-        .db
-        .get_bounty(&id)
-        .await?
-        .ok_or_else(|| AppError::NotFound(format!("bounty {id} not found")))?;
+    let not_found = || AppError::NotFound(format!("bounty {id} not found"));
+
+    let bounty = state.db.get_bounty(&id).await?.ok_or_else(not_found)?;
+
+    let caller = auth.as_ref().map(|e| e.0 .0.as_str());
+    if crate::api::authorize_repo_read(&state, &bounty.repo_owner, &bounty.repo_name, caller, "/")
+        .await
+        .is_err()
+    {
+        return Err(not_found());
+    }
+
    Ok(Json(bounty))
 }

@@ -162,11 +238,22 @@ pub async fn claim_bounty(
    Path(id): Path<String>,
    Json(req): Json<ClaimBountyRequest>,
 ) -> Result<Json<BountyRecord>> {
-    let bounty = state
-        .db
-        .get_bounty(&id)
-        .await?
-        .ok_or_else(|| AppError::NotFound(format!("bounty {id} not found")))?;
+    let not_found = || AppError::NotFound(format!("bounty {id} not found"));
+
+    let bounty = state.db.get_bounty(&id).await?.ok_or_else(not_found)?;
+
+    if crate::api::authorize_repo_read(
+        &state,
+        &bounty.repo_owner,
+        &bounty.repo_name,
+        Some(auth.0.as_str()),
+        "/",
+    )
+    .await
+    .is_err()
+    {
+        return Err(not_found());
+    }

    if bounty.status != "open" {
        return Err(AppError::BadRequest(format!(
@@ -1,23 +1,44 @@
 //! API handlers for ref certificates.

-use axum::extract::{Path, State};
+use std::collections::HashMap;
+
+use axum::extract::{Extension, Path, Query, State};
 use axum::Json;

+use crate::auth::AuthenticatedDid;
 use crate::error::{AppError, Result};
 use crate::state::AppState;

-/// GET /api/v1/repos/{owner}/{repo}/certs
+/// GET /api/v1/repos/{owner}/{repo}/certs?limit=50
 pub async fn list_certs(
    State(state): State<AppState>,
    Path((owner, name)): Path<(String, String)>,
+    Query(params): Query<HashMap<String, String>>,
+    auth: Option<Extension<AuthenticatedDid>>,
 ) -> Result<Json<serde_json::Value>> {
-    let record = state
-        .db
-        .get_repo(&owner, &name)
-        .await?
-        .ok_or_else(|| AppError::RepoNotFound(format!("{owner}/{name}")))?;
+    let limit = params
+        .get("limit")
+        .and_then(|v| v.parse::<i64>().ok())
+        .map(|v| v.max(1))
+        .unwrap_or(50)
+        .min(200);

-    let certs = state.db.list_ref_certificates(&record.id).await?;
+    let caller = auth.as_ref().map(|e| e.0 .0.as_str());
+    let (record, _rules) =
+        crate::api::authorize_repo_read(&state, &owner, &name, caller, "/").await?;
+
+    // When a prefix is given (short-ID resolution from the CLI) use a
+    // generous limit and delegate to the prefix-matched query so the
+    // caller can resolve IDs regardless of how many certs exist.
+    let prefix = params.get("prefix").filter(|p| !p.is_empty());
+    let certs = if let Some(prefix) = prefix {
+        state
+            .db
+            .list_ref_certificates_by_prefix(&record.id, prefix, 200)
+            .await?
+    } else {
+        state.db.list_ref_certificates(&record.id, limit).await?
+    };
    let certs_json: Vec<serde_json::Value> = certs
        .iter()
        .map(|c| {
@@ -35,20 +56,21 @@ pub async fn list_certs(
        })
        .collect();

-    Ok(Json(serde_json::json!({ "certificates": certs_json })))
+    let count = certs_json.len();
+    Ok(Json(
+        serde_json::json!({ "certificates": certs_json, "count": count }),
+    ))
 }

 /// GET /api/v1/repos/{owner}/{repo}/certs/{id}
 pub async fn get_cert(
    State(state): State<AppState>,
    Path((owner, name, id)): Path<(String, String, String)>,
+    auth: Option<Extension<AuthenticatedDid>>,
 ) -> Result<Json<serde_json::Value>> {
-    // Verify the repo exists
-    let _record = state
-        .db
-        .get_repo(&owner, &name)
-        .await?
-        .ok_or_else(|| AppError::RepoNotFound(format!("{owner}/{name}")))?;
+    let caller = auth.as_ref().map(|e| e.0 .0.as_str());
+    let (record, _rules) =
+        crate::api::authorize_repo_read(&state, &owner, &name, caller, "/").await?;

    let cert = state
        .db
@@ -56,6 +78,10 @@ pub async fn get_cert(
        .await?
        .ok_or_else(|| AppError::NotFound(format!("certificate {id}")))?;

+    if cert.repo_id != record.id {
+        return Err(AppError::NotFound(format!("certificate {id}")));
+    }
+
    Ok(Json(serde_json::json!({
        "id":         cert.id,
        "repo_id":    cert.repo_id,
@@ -129,6 +129,7 @@ pub async fn list_ref_updates(
    let limit = params
        .get("limit")
        .and_then(|v| v.parse::<i64>().ok())
+        .map(|v| v.max(0))
        .unwrap_or(50)
        .clamp(0, MAX_VISIBLE_REF_UPDATES);

@@ -177,6 +178,7 @@ pub async fn list_repo_events(
    let limit = params
        .get("limit")
        .and_then(|v| v.parse::<i64>().ok())
+        .map(|v| v.max(0))
        .unwrap_or(50)
        .clamp(0, MAX_VISIBLE_REF_UPDATES);

@@ -209,7 +211,7 @@ pub async fn list_repo_events(
    // into an empty 200, matching the gossip half below.
    let cert_events: Vec<serde_json::Value> = state
        .db
-        .list_ref_certificates(&record.id)
+        .list_ref_certificates(&record.id, limit)
        .await?
        .iter()
        .map(|c| {
@@ -61,11 +61,14 @@ pub async fn create_issue(
    let json_str = serde_json::to_string(&issue)
        .map_err(|e| AppError::BadRequest(format!("serialization error: {e}")))?;

+    // Shed 503 + Retry-After on an exhausted write-lock POOL instead of a generic
+    // git 500 (#173 F1). This path holds no admission permit, so it reaches the pool
+    // unthrottled; reuse the push handler's mapping so the two cannot drift.
    let guard = state
        .repo_store
        .acquire_write(&record.owner_did, &record.name)
        .await
-        .map_err(|e| AppError::Git(e.to_string()))?;
+        .map_err(|e| crate::api::repos::acquire_write_app_error(&e, &repo))?;
    let disk_path = guard.path().to_path_buf();

    let create_result = git_issues::create_issue(&disk_path, &issue_id, &json_str);
@@ -90,12 +93,11 @@ pub async fn create_issue(
 pub async fn list_issues(
    State(state): State<AppState>,
    Path((owner, repo)): Path<(String, String)>,
+    auth: Option<Extension<AuthenticatedDid>>,
 ) -> Result<Json<serde_json::Value>> {
-    let record = state
-        .db
-        .get_repo(&owner, &repo)
-        .await?
-        .ok_or_else(|| AppError::RepoNotFound(format!("{owner}/{repo}")))?;
+    let caller = auth.as_ref().map(|e| e.0 .0.as_str());
+    let (record, _rules) =
+        crate::api::authorize_repo_read(&state, &owner, &repo, caller, "/").await?;

    let disk_path = state
        .repo_store
@@ -120,12 +122,11 @@ pub async fn list_issues(
 pub async fn get_issue(
    State(state): State<AppState>,
    Path((owner, repo, issue_id)): Path<(String, String, String)>,
+    auth: Option<Extension<AuthenticatedDid>>,
 ) -> Result<Json<serde_json::Value>> {
-    let record = state
-        .db
-        .get_repo(&owner, &repo)
-        .await?
-        .ok_or_else(|| AppError::RepoNotFound(format!("{owner}/{repo}")))?;
+    let caller = auth.as_ref().map(|e| e.0 .0.as_str());
+    let (record, _rules) =
+        crate::api::authorize_repo_read(&state, &owner, &repo, caller, "/").await?;

    let disk_path = state
        .repo_store
@@ -191,14 +192,31 @@ pub async fn create_issue_comment(
 pub async fn list_issue_comments(
    State(state): State<AppState>,
    Path((owner, repo, issue_id)): Path<(String, String, String)>,
+    auth: Option<Extension<AuthenticatedDid>>,
 ) -> Result<Json<serde_json::Value>> {
-    let _record = state
-        .db
-        .get_repo(&owner, &repo)
-        .await?
-        .ok_or_else(|| AppError::RepoNotFound(format!("{owner}/{repo}")))?;
+    let caller = auth.as_ref().map(|e| e.0 .0.as_str());
+    let (record, _rules) =
+        crate::api::authorize_repo_read(&state, &owner, &repo, caller, "/").await?;

-    let comments = state.db.list_issue_comments(&issue_id).await?;
+    let disk_path = state
+        .repo_store
+        .acquire(&record.owner_did, &record.name)
+        .await
+        .map_err(|e| AppError::Git(e.to_string()))?;
+    // Resolve the full issue ID (accepts 8-char prefix) so the DB fetch
+    // below uses the same canonical id as the git ref.
+    let full_id = match git_issues::resolve_issue_id(&disk_path, &issue_id)
+        .map_err(|e| AppError::Git(e.to_string()))?
+    {
+        Some(id) => id,
+        None => {
+            return Err(AppError::RepoNotFound(format!(
+                "issue {issue_id} not found"
+            )))
+        }
+    };
+
+    let comments = state.db.list_issue_comments(&full_id).await?;
    Ok(Json(serde_json::json!({ "comments": comments })))
 }

@@ -214,11 +232,13 @@ pub async fn close_issue(
        .await?
        .ok_or_else(|| AppError::RepoNotFound(format!("{owner}/{repo}")))?;

+    // Same capacity shed as create_issue above (#173 F1): an exhausted write-lock
+    // pool is a 503 + Retry-After, not a 500 git error.
    let guard = state
        .repo_store
        .acquire_write(&record.owner_did, &record.name)
        .await
-        .map_err(|e| AppError::Git(e.to_string()))?;
+        .map_err(|e| crate::api::repos::acquire_write_app_error(&e, &repo))?;
    let disk_path = guard.path().to_path_buf();

    // Owner OR issue author may close. The author lives in the issue's git-JSON
@@ -264,3 +284,168 @@ pub async fn close_issue(

    Ok(Json(issue))
 }
+
+/// #173 F1 follow-up: the two issue write paths reach `acquire_write` holding NO
+/// admission permit (unlike the push handler, which is capped by the git-push
+/// semaphore), so they are the callers most likely to meet an exhausted write-lock
+/// POOL under load. An exhausted pool is a capacity signal, so both must shed
+/// 503 + Retry-After (`AppError::Overloaded`) the way the push handler does, not
+/// report the generic 500 git error that says nothing about retrying.
+#[cfg(test)]
+mod lock_pool_shed_tests {
+    use super::*;
+    use axum::response::IntoResponse;
+    use sqlx::PgPool;
+
+    fn seed_repo(owner_did: &str, name: &str) -> crate::db::RepoRecord {
+        let now = Utc::now();
+        crate::db::RepoRecord {
+            id: Uuid::new_v4().to_string(),
+            name: name.to_string(),
+            owner_did: owner_did.to_string(),
+            description: None,
+            is_public: true,
+            default_branch: "main".to_string(),
+            created_at: now,
+            updated_at: now,
+            disk_path: format!("/tmp/{name}"),
+            forked_from: None,
+            machine_id: None,
+        }
+    }
+
+    /// State whose repo store draws write locks from a ONE-connection pool with a
+    /// short checkout timeout, so a single held guard exhausts it promptly rather
+    /// than at the pool default.
+    async fn one_connection_lock_pool_state(pool: &PgPool) -> AppState {
+        let mut state = crate::test_support::test_state(pool.clone()).await;
+        state.repo_store = crate::git::repo_store::RepoStore::new(
+            std::path::PathBuf::from("/tmp/gitlawb-issues-lockpool"),
+            None,
+            crate::git::repo_store::build_lock_pool(pool, 1, std::time::Duration::from_secs(1)),
+        );
+        state
+    }
+
+    /// The shed must be a real 503 carrying Retry-After, not just an internal enum
+    /// variant: assert on the rendered response so a remapping of `Overloaded` is
+    /// caught here too.
+    fn assert_sheds_503_with_retry_after(err: AppError, what: &str) {
+        let resp = err.into_response();
+        assert_eq!(
+            resp.status(),
+            StatusCode::SERVICE_UNAVAILABLE,
+            "{what}: an exhausted write-lock pool must shed 503, not a 500 git error"
+        );
+        assert_eq!(
+            resp.headers()
+                .get("retry-after")
+                .map(|v| v.to_str().unwrap()),
+            Some("1"),
+            "{what}: a capacity shed must tell the client when to retry"
+        );
+    }
+
+    /// RED-before/GREEN-after for `create_issue`. Both directions: the shed while the
+    /// only lock-pool connection is held by a guard on a DIFFERENT repo (so this is
+    /// pool capacity, not advisory-lock contention on this repo), and the must-not
+    /// case once that connection is back.
+    #[sqlx::test]
+    async fn create_issue_lock_pool_exhaustion_sheds_503_not_500(pool: PgPool) {
+        let owner = "did:key:zISSUECREATELOCKPOOLAAAAAAAAAAAAAAAAAAAA";
+        let state = one_connection_lock_pool_state(&pool).await;
+        state
+            .db
+            .create_repo(&seed_repo(owner, "lp-create"))
+            .await
+            .expect("seed repo");
+
+        let held = state
+            .repo_store
+            .acquire_write(owner, "other-repo")
+            .await
+            .expect("the first write takes the only lock-pool connection");
+
+        let shed = create_issue(
+            State(state.clone()),
+            Extension(AuthenticatedDid(owner.to_string())),
+            Path((owner.to_string(), "lp-create".to_string())),
+            Json(CreateIssueRequest {
+                title: "t".to_string(),
+                body: None,
+                signed_payload: None,
+            }),
+        )
+        .await;
+        let err = shed.expect_err("an exhausted lock pool must fail the call");
+        assert_sheds_503_with_retry_after(err, "create_issue");
+
+        // MUST-NOT: with the pool free again the call is not shed as capacity (it
+        // fails later on the nonexistent on-disk repo, which is a git 500).
+        held.release(false).await;
+        let admitted = create_issue(
+            State(state.clone()),
+            Extension(AuthenticatedDid(owner.to_string())),
+            Path((owner.to_string(), "lp-create".to_string())),
+            Json(CreateIssueRequest {
+                title: "t".to_string(),
+                body: None,
+                signed_payload: None,
+            }),
+        )
+        .await;
+        assert!(
+            !matches!(admitted, Err(AppError::Overloaded(_))),
+            "with the lock pool free, create_issue must not be shed as capacity; got {:?}",
+            admitted.err()
+        );
+    }
+
+    /// RED-before/GREEN-after for `close_issue`, same two directions.
+    #[sqlx::test]
+    async fn close_issue_lock_pool_exhaustion_sheds_503_not_500(pool: PgPool) {
+        let owner = "did:key:zISSUECLOSELOCKPOOLBBBBBBBBBBBBBBBBBBBBB";
+        let state = one_connection_lock_pool_state(&pool).await;
+        state
+            .db
+            .create_repo(&seed_repo(owner, "lp-close"))
+            .await
+            .expect("seed repo");
+
+        let held = state
+            .repo_store
+            .acquire_write(owner, "other-repo")
+            .await
+            .expect("the first write takes the only lock-pool connection");
+
+        let shed = close_issue(
+            State(state.clone()),
+            Extension(AuthenticatedDid(owner.to_string())),
+            Path((
+                owner.to_string(),
+                "lp-close".to_string(),
+                "deadbeef".to_string(),
+            )),
+        )
+        .await;
+        let err = shed.expect_err("an exhausted lock pool must fail the call");
+        assert_sheds_503_with_retry_after(err, "close_issue");
+
+        held.release(false).await;
+        let admitted = close_issue(
+            State(state.clone()),
+            Extension(AuthenticatedDid(owner.to_string())),
+            Path((
+                owner.to_string(),
+                "lp-close".to_string(),
+                "deadbeef".to_string(),
+            )),
+        )
+        .await;
+        assert!(
+            !matches!(admitted, Err(AppError::Overloaded(_))),
+            "with the lock pool free, close_issue must not be shed as capacity; got {:?}",
+            admitted.err()
+        );
+    }
+}
@@ -74,12 +74,11 @@ pub async fn remove_label(
 pub async fn list_labels(
    State(state): State<AppState>,
    Path((owner, name)): Path<(String, String)>,
+    auth: Option<Extension<AuthenticatedDid>>,
 ) -> Result<Json<serde_json::Value>> {
-    let record = state
-        .db
-        .get_repo(&owner, &name)
-        .await?
-        .ok_or_else(|| AppError::RepoNotFound(format!("{owner}/{name}")))?;
+    let caller = auth.as_ref().map(|e| e.0 .0.as_str());
+    let (record, _rules) =
+        crate::api::authorize_repo_read(&state, &owner, &name, caller, "/").await?;

    let labels = state.db.list_labels(&record.id).await?;
    Ok(Json(serde_json::json!({ "labels": labels })))
@@ -114,6 +114,12 @@ mod did_tests {
        assert!(!did_matches("did:key:zABC", "did:key:zXYZ"));
        assert!(!did_matches("zABC", "zXYZ"));
    }
+
+    #[test]
+    fn empty_did_matches() {
+        assert!(did_matches("", ""));
+        assert!(did_matches("", "did:key:"));
+    }
 }

 /// Drift guard (plan 002 §Gate-type table, Step 5). Every in-scope mutation
@@ -194,9 +200,11 @@ mod authz_guard {
            (issues, "create_issue", "authorize_repo_read("),
            (bounties, "create_bounty", "authorize_repo_read("),
            (repos, "fork_repo", "authorize_repo_read("),
-            // get_by_cid gates each iterated repo row directly via visibility_check
-            // (KTD2a: it must NOT route through authorize_repo_read's fuzzy re-resolve).
-            (ipfs, "get_by_cid", "visibility_check("),
+            // get_by_cid resolves each candidate (provenance path + legacy scan) through
+            // the shared `gate_and_serve` (#173 round 2); the gate markers themselves are
+            // asserted below. This row proves the delegation is real — the gate is
+            // actually reached, not dead code.
+            (ipfs, "get_by_cid", "gate_and_serve("),
            // Bucket C — signer-self: the acting DID is matched/bound to auth.0
            (tasks, "create_task", "did_matches("),
            (tasks, "claim_task", "did_matches("),
@@ -230,6 +238,22 @@ mod authz_guard {
            "visibility::require_owner must use did_matches for DID-safe owner matching"
        );

+        // The CID read surface (#173) enforces its gate inside the shared
+        // `gate_and_serve`, which BOTH the provenance path and the legacy scan call, so
+        // the markers must live there (the get_by_cid row above only proves delegation).
+        // The repo's own "/" visibility check (KTD2a — never authorize_repo_read's fuzzy
+        // re-resolve) and the quarantine hard-drop BEFORE visibility (INV-11) are both
+        // load-bearing: removing either re-opens a leak on the provenance path.
+        let gate_body = fn_body(ipfs, "gate_and_serve");
+        assert!(
+            gate_body.contains("visibility_check("),
+            "gate_and_serve must gate the CID read surface via visibility_check (KTD2a)"
+        );
+        assert!(
+            gate_body.contains("if quarantined"),
+            "gate_and_serve must hard-drop a quarantined repo before the visibility gate (INV-11)"
+        );
+
        for (src, func, marker) in rows {
            let body = fn_body(src, func);
            assert!(
@@ -504,14 +528,6 @@ mod authz_guard {
        // Repo-scoped reads known to be ungated today, each tracked by an issue.
        // Remove an entry the moment its gate lands (the staleness assert enforces it).
        let known_ungated: &[(&str, &str)] = &[
-            ("list_certs", "#120"),
-            ("get_cert", "#120"),
-            ("list_issues", "#120"),
-            ("get_issue", "#120"),
-            ("list_issue_comments", "#120"),
-            ("list_labels", "#120"),
-            ("list_repo_bounties", "#120"),
-            ("get_star_status", "#120"),
            ("list_webhooks", "#94 (PR #113)"),
            ("list_replicas", "PR #113"),
            ("list_protected_branches", "PR #113"),
@@ -537,4 +537,458 @@ mod tests {
        // pins the `o[0] == 0` check against an off-by-one into 1.x.
        assert!(is_public_http_url("http://1.0.0.0/"));
    }
+
+    // ── #82: /sync/trigger signature gate + per-IP brake on the peer-sync routes ──
+    //
+    // These drive the FULL production router (crate::server::build_router) so the
+    // route wiring, layer order, and config-mode branching are all under test.
+    // The positive-path and DID-agnostic cases mount the handler directly because
+    // signed_request_as injects only an AuthenticatedDid extension (not a real
+    // RFC-9421 signature), which require_signature rejects on the full router.
+    use crate::rate_limit::{IpRateLimiter, RateLimiter, TrustedProxy};
+    use crate::state::AppState;
+    use crate::test_support::{signed_request_as, test_state};
+    use axum::body::Body;
+    use axum::extract::ConnectInfo;
+    use axum::http::{header, Method, Request, StatusCode};
+    use axum::routing::post;
+    use axum::{middleware, Extension, Router};
+    use gitlawb_core::http_sig::sign_request;
+    use gitlawb_core::identity::Keypair;
+    use sqlx::PgPool;
+    use std::net::SocketAddr;
+    use std::sync::Arc;
+    use std::time::Duration;
+    use tower::ServiceExt;
+
+    fn unsigned_post(uri: &str, body: &str, peer: &str) -> Request<Body> {
+        let mut req = Request::builder()
+            .method(Method::POST)
+            .uri(uri)
+            .header(header::CONTENT_TYPE, "application/json")
+            .body(Body::from(body.to_string()))
+            .unwrap();
+        req.extensions_mut()
+            .insert(ConnectInfo(peer.parse::<SocketAddr>().unwrap()));
+        req
+    }
+
+    fn require_signed_peer_writes(state: &mut AppState) {
+        let mut cfg = (*state.config).clone();
+        cfg.require_signed_peer_writes = true;
+        state.config = Arc::new(cfg);
+    }
+
+    const NOTIFY_BODY: &str = r#"{"repo":"demo","ref_name":"refs/heads/main","new_sha":"0000000000000000000000000000000000000000","node_did":"PEER_DID"}"#;
+
+    // ── trigger: mandatory signature ──────────────────────────────────────────
+
+    #[sqlx::test]
+    async fn sync_trigger_rejects_unsigned_in_default_mode(pool: PgPool) {
+        // The hole: with require_signed_peer_writes=false (default), an anonymous
+        // caller reaches the fan-out. Must be 401 regardless of the flag.
+        let state = test_state(pool).await;
+        let router = crate::server::build_router(state);
+        let resp = router
+            .oneshot(unsigned_post(
+                "/api/v1/sync/trigger",
+                "{}",
+                "203.0.113.1:5000",
+            ))
+            .await
+            .unwrap();
+        assert_eq!(resp.status(), StatusCode::UNAUTHORIZED);
+    }
+
+    #[sqlx::test]
+    async fn sync_trigger_rejects_unsigned_in_signed_writes_mode(pool: PgPool) {
+        // The signature requirement must not depend on the flag.
+        let mut state = test_state(pool).await;
+        require_signed_peer_writes(&mut state);
+        let router = crate::server::build_router(state);
+        let resp = router
+            .oneshot(unsigned_post(
+                "/api/v1/sync/trigger",
+                "{}",
+                "203.0.113.2:5000",
+            ))
+            .await
+            .unwrap();
+        assert_eq!(resp.status(), StatusCode::UNAUTHORIZED);
+    }
+
+    #[sqlx::test]
+    async fn sync_trigger_admits_signed_caller(pool: PgPool) {
+        // must-not-over-throttle: a signed caller reaches the handler and (with no
+        // peers seeded) gets 200, not 429. Direct-mount because a real signature
+        // cannot be forged through the full router in tests.
+        let state = test_state(pool).await;
+        let did = Keypair::generate().did().to_string();
+        let app = Router::new()
+            .route("/api/v1/sync/trigger", post(super::trigger_sync))
+            .layer(middleware::from_fn(crate::rate_limit::rate_limit_by_ip))
+            .layer(Extension(IpRateLimiter {
+                limiter: RateLimiter::new(60, Duration::from_secs(3600)),
+                trust: TrustedProxy::None,
+            }))
+            .with_state(state);
+        let mut req =
+            signed_request_as(&did, Method::POST, "/api/v1/sync/trigger", Body::from("{}"));
+        req.extensions_mut().insert(ConnectInfo(
+            "203.0.113.3:5000".parse::<SocketAddr>().unwrap(),
+        ));
+        let resp = app.oneshot(req).await.unwrap();
+        assert_eq!(resp.status(), StatusCode::OK);
+    }
+
+    // ── trigger: IP brake ─────────────────────────────────────────────────────
+
+    #[sqlx::test]
+    async fn sync_trigger_ip_flood_is_throttled(pool: PgPool) {
+        // The brake is outermost, so an over-limit request 429s before it ever
+        // reaches require_signature — an unsigned request suffices to prove it.
+        let mut state = test_state(pool).await;
+        state.sync_trigger_rate_limiter = RateLimiter::new(1, Duration::from_secs(3600));
+        state.push_limiter_trust = TrustedProxy::None;
+        let peer = "203.0.113.4:5000";
+        // Exhaust the single-request budget up front.
+        assert!(
+            state
+                .sync_trigger_rate_limiter
+                .check(&peer.parse::<SocketAddr>().unwrap().ip().to_string())
+                .await
+        );
+        let router = crate::server::build_router(state);
+        let resp = router
+            .oneshot(unsigned_post("/api/v1/sync/trigger", "{}", peer))
+            .await
+            .unwrap();
+        assert_eq!(resp.status(), StatusCode::TOO_MANY_REQUESTS);
+    }
+
+    #[sqlx::test]
+    async fn sync_trigger_brake_is_did_agnostic(pool: PgPool) {
+        // Why per-IP, not per-DID: a DID farm (fresh did:key per request) does not
+        // bypass an IP-keyed brake. Two DISTINCT DIDs from one IP, brake limit 1 →
+        // the second is 429. A per-DID limiter would give each DID its own bucket.
+        let state = test_state(pool).await;
+        let app = Router::new()
+            .route("/api/v1/sync/trigger", post(super::trigger_sync))
+            .layer(middleware::from_fn(crate::rate_limit::rate_limit_by_ip))
+            .layer(Extension(IpRateLimiter {
+                limiter: RateLimiter::new(1, Duration::from_secs(3600)),
+                trust: TrustedProxy::None,
+            }))
+            .with_state(state);
+        let peer = "203.0.113.5:5000".parse::<SocketAddr>().unwrap();
+        let mk = |did: &str| {
+            let mut r =
+                signed_request_as(did, Method::POST, "/api/v1/sync/trigger", Body::from("{}"));
+            r.extensions_mut().insert(ConnectInfo(peer));
+            r
+        };
+        let first = app
+            .clone()
+            .oneshot(mk(&Keypair::generate().did().to_string()))
+            .await
+            .unwrap();
+        assert_eq!(first.status(), StatusCode::OK);
+        let second = app
+            .oneshot(mk(&Keypair::generate().did().to_string()))
+            .await
+            .unwrap();
+        assert_eq!(second.status(), StatusCode::TOO_MANY_REQUESTS);
+    }
+
+    #[sqlx::test]
+    async fn sync_trigger_forged_forwarded_header_cannot_bypass(pool: PgPool) {
+        // TrustedProxy::None keys on the socket peer, so rotating X-Forwarded-For
+        // from one socket peer does not refill the bucket. limit 1: first request
+        // consumes it (then 401 unsigned), second from the same socket → 429
+        // regardless of a different XFF value.
+        let mut state = test_state(pool).await;
+        state.sync_trigger_rate_limiter = RateLimiter::new(1, Duration::from_secs(3600));
+        state.push_limiter_trust = TrustedProxy::None;
+        let router = crate::server::build_router(state);
+        let mut a = unsigned_post("/api/v1/sync/trigger", "{}", "203.0.113.6:5000");
+        a.headers_mut()
+            .insert("x-forwarded-for", "1.1.1.1".parse().unwrap());
+        assert_eq!(
+            router.clone().oneshot(a).await.unwrap().status(),
+            StatusCode::UNAUTHORIZED
+        );
+        let mut b = unsigned_post("/api/v1/sync/trigger", "{}", "203.0.113.6:5000");
+        b.headers_mut()
+            .insert("x-forwarded-for", "2.2.2.2".parse().unwrap());
+        assert_eq!(
+            router.oneshot(b).await.unwrap().status(),
+            StatusCode::TOO_MANY_REQUESTS
+        );
+    }
+
+    #[sqlx::test]
+    async fn sync_trigger_rate_limit_zero_disables_but_signature_holds(pool: PgPool) {
+        // 0 disables the brake (RateLimiter::check early-returns), proving the two
+        // halves are independent: no 429 even under a flood, but the signature gate
+        // still 401s every unsigned request.
+        let mut state = test_state(pool).await;
+        state.sync_trigger_rate_limiter = RateLimiter::new(0, Duration::from_secs(3600));
+        state.push_limiter_trust = TrustedProxy::None;
+        let router = crate::server::build_router(state);
+        for _ in 0..3 {
+            let resp = router
+                .clone()
+                .oneshot(unsigned_post(
+                    "/api/v1/sync/trigger",
+                    "{}",
+                    "203.0.113.7:5000",
+                ))
+                .await
+                .unwrap();
+            assert_eq!(resp.status(), StatusCode::UNAUTHORIZED);
+        }
+    }
+
+    // ── notify: braked, but signature behavior unchanged ──────────────────────
+
+    async fn seed_peer(state: &AppState) -> String {
+        let did = Keypair::generate().did().to_string();
+        state
+            .db
+            .upsert_peer(&did, "https://peer.example.com")
+            .await
+            .unwrap();
+        did
+    }
+
+    #[sqlx::test]
+    async fn sync_notify_unsigned_flood_is_throttled(pool: PgPool) {
+        // notify still accepts an unsigned known-peer notification (rolling-upgrade
+        // compat), but a flood from one IP is now braked. brake limit 1: first
+        // enqueues (200), second from the same IP → 429.
+        let mut state = test_state(pool).await;
+        state.peer_write_rate_limiter = RateLimiter::new(1, Duration::from_secs(3600));
+        state.push_limiter_trust = TrustedProxy::None;
+        let peer_did = seed_peer(&state).await;
+        let body = NOTIFY_BODY.replace("PEER_DID", &peer_did);
+        let router = crate::server::build_router(state);
+        let first = router
+            .clone()
+            .oneshot(unsigned_post(
+                "/api/v1/sync/notify",
+                &body,
+                "203.0.113.8:5000",
+            ))
+            .await
+            .unwrap();
+        assert_eq!(first.status(), StatusCode::OK);
+        let second = router
+            .oneshot(unsigned_post(
+                "/api/v1/sync/notify",
+                &body,
+                "203.0.113.8:5000",
+            ))
+            .await
+            .unwrap();
+        assert_eq!(second.status(), StatusCode::TOO_MANY_REQUESTS);
+    }
+
+    #[sqlx::test]
+    async fn sync_notify_distinct_ips_are_not_collaterally_throttled(pool: PgPool) {
+        // must-not-over-throttle: per-IP keying means one peer's volume does not
+        // throttle another. brake limit 1, two DIFFERENT source IPs → both 200.
+        let mut state = test_state(pool).await;
+        state.peer_write_rate_limiter = RateLimiter::new(1, Duration::from_secs(3600));
+        state.push_limiter_trust = TrustedProxy::None;
+        let peer_did = seed_peer(&state).await;
+        let body = NOTIFY_BODY.replace("PEER_DID", &peer_did);
+        let router = crate::server::build_router(state);
+        for ip in ["203.0.113.20:5000", "203.0.113.21:5000"] {
+            let resp = router
+                .clone()
+                .oneshot(unsigned_post("/api/v1/sync/notify", &body, ip))
+                .await
+                .unwrap();
+            assert_eq!(
+                resp.status(),
+                StatusCode::OK,
+                "distinct IP {ip} must not be throttled"
+            );
+        }
+    }
+
+    #[sqlx::test]
+    async fn notify_flood_does_not_exhaust_trigger_bucket(pool: PgPool) {
+        // Separate buckets: draining peer_write via an unsigned notify flood must
+        // NOT throttle the signed trigger caller from the same IP. After the notify
+        // bucket is spent, an unsigned trigger from that IP hits its own (unspent)
+        // bucket and is rejected by the SIGNATURE gate (401), not the brake (429).
+        let mut state = test_state(pool).await;
+        state.peer_write_rate_limiter = RateLimiter::new(1, Duration::from_secs(3600));
+        state.sync_trigger_rate_limiter = RateLimiter::new(60, Duration::from_secs(3600));
+        state.push_limiter_trust = TrustedProxy::None;
+        let peer_did = seed_peer(&state).await;
+        let body = NOTIFY_BODY.replace("PEER_DID", &peer_did);
+        let router = crate::server::build_router(state);
+        let ip = "203.0.113.9:5000";
+        assert_eq!(
+            router
+                .clone()
+                .oneshot(unsigned_post("/api/v1/sync/notify", &body, ip))
+                .await
+                .unwrap()
+                .status(),
+            StatusCode::OK
+        );
+        assert_eq!(
+            router
+                .clone()
+                .oneshot(unsigned_post("/api/v1/sync/notify", &body, ip))
+                .await
+                .unwrap()
+                .status(),
+            StatusCode::TOO_MANY_REQUESTS,
+            "peer_write bucket should now be exhausted for this IP"
+        );
+        let trigger = router
+            .oneshot(unsigned_post("/api/v1/sync/trigger", "{}", ip))
+            .await
+            .unwrap();
+        assert_eq!(
+            trigger.status(),
+            StatusCode::UNAUTHORIZED,
+            "trigger must hit its own bucket (401 from the sig gate), not the drained peer_write bucket (429)"
+        );
+    }
+
+    #[sqlx::test]
+    async fn announce_still_accepts_unsigned_in_default_mode(pool: PgPool) {
+        // must-not-over-reach: adding the brake must not tighten announce's
+        // rolling-upgrade behavior — an unsigned announce with a public URL still
+        // succeeds (it only gains the brake, which a single request is under).
+        let state = test_state(pool).await;
+        let did = Keypair::generate().did().to_string();
+        let body = format!(r#"{{"did":"{did}","http_url":"https://peer.example.com"}}"#);
+        let router = crate::server::build_router(state);
+        let resp = router
+            .oneshot(unsigned_post(
+                "/api/v1/peers/announce",
+                &body,
+                "203.0.113.10:5000",
+            ))
+            .await
+            .unwrap();
+        assert_eq!(resp.status(), StatusCode::OK);
+    }
+
+    // Build a request carrying a REAL RFC 9421 signature (not just an injected
+    // extension), so it passes require_signature on the full production router.
+    fn real_signed_trigger(peer: &str) -> Request<Body> {
+        let kp = Keypair::generate();
+        let body = b"{}";
+        let s = sign_request(&kp, "POST", "/api/v1/sync/trigger", body);
+        let mut req = Request::builder()
+            .method(Method::POST)
+            .uri("/api/v1/sync/trigger")
+            .header(header::CONTENT_TYPE, "application/json")
+            .header("content-digest", s.content_digest)
+            .header("signature-input", s.signature_input)
+            .header("signature", s.signature)
+            .body(Body::from(body.to_vec()))
+            .unwrap();
+        req.extensions_mut()
+            .insert(ConnectInfo(peer.parse::<SocketAddr>().unwrap()));
+        req
+    }
+
+    #[sqlx::test]
+    async fn sync_trigger_admits_real_signature_through_full_router(pool: PgPool) {
+        // The positive path through the REAL gate: a validly-signed trigger passes
+        // require_signature on the full router and reaches the handler (no peers
+        // seeded → 200), in BOTH config modes.
+        let state = test_state(pool.clone()).await;
+        let resp = crate::server::build_router(state)
+            .oneshot(real_signed_trigger("203.0.113.30:5000"))
+            .await
+            .unwrap();
+        assert_eq!(
+            resp.status(),
+            StatusCode::OK,
+            "a real signature must reach the handler (default mode)"
+        );
+
+        let mut state = test_state(pool).await;
+        require_signed_peer_writes(&mut state);
+        let resp = crate::server::build_router(state)
+            .oneshot(real_signed_trigger("203.0.113.30:5001"))
+            .await
+            .unwrap();
+        assert_eq!(
+            resp.status(),
+            StatusCode::OK,
+            "a real signature must reach the handler (signed-writes mode)"
+        );
+    }
+
+    #[sqlx::test]
+    async fn announce_flood_is_throttled(pool: PgPool) {
+        // The peer_write brake covers /peers/announce too (co-benefit): limit 1,
+        // first unsigned announce from an IP is 200, the second from that IP 429.
+        let mut state = test_state(pool).await;
+        state.peer_write_rate_limiter = RateLimiter::new(1, Duration::from_secs(3600));
+        state.push_limiter_trust = TrustedProxy::None;
+        let did = Keypair::generate().did().to_string();
+        let body = format!(r#"{{"did":"{did}","http_url":"https://peer.example.com"}}"#);
+        let router = crate::server::build_router(state);
+        let ip = "203.0.113.31:5000";
+        assert_eq!(
+            router
+                .clone()
+                .oneshot(unsigned_post("/api/v1/peers/announce", &body, ip))
+                .await
+                .unwrap()
+                .status(),
+            StatusCode::OK
+        );
+        assert_eq!(
+            router
+                .oneshot(unsigned_post("/api/v1/peers/announce", &body, ip))
+                .await
+                .unwrap()
+                .status(),
+            StatusCode::TOO_MANY_REQUESTS,
+            "announce must be braked by the peer_write limiter"
+        );
+    }
+
+    #[sqlx::test]
+    async fn sync_trigger_429_body_is_generic_not_push(pool: PgPool) {
+        // The shared 429 middleware now serves the sync routes, so its body must
+        // not claim "push" (RED before the message was genericized).
+        let mut state = test_state(pool).await;
+        state.sync_trigger_rate_limiter = RateLimiter::new(1, Duration::from_secs(3600));
+        state.push_limiter_trust = TrustedProxy::None;
+        let peer = "203.0.113.32:5000";
+        assert!(
+            state
+                .sync_trigger_rate_limiter
+                .check(&peer.parse::<SocketAddr>().unwrap().ip().to_string())
+                .await
+        );
+        let router = crate::server::build_router(state);
+        let resp = router
+            .oneshot(unsigned_post("/api/v1/sync/trigger", "{}", peer))
+            .await
+            .unwrap();
+        assert_eq!(resp.status(), StatusCode::TOO_MANY_REQUESTS);
+        let bytes = axum::body::to_bytes(resp.into_body(), usize::MAX)
+            .await
+            .unwrap();
+        let s = String::from_utf8_lossy(&bytes);
+        assert!(s.contains("rate limit exceeded"), "429 body: {s:?}");
+        assert!(
+            !s.contains("push"),
+            "a 429 on a sync route must not say 'push': {s:?}"
+        );
+    }
 }
@@ -98,7 +98,7 @@ pub async fn set_profile(
                    &state.http_client,
                    &state.config.pinata_upload_url,
                    &state.config.pinata_jwt,
-                    &format!("profile-{}", &did),
+                    &format!("profile-{}", did),
                    &profile_json,
                )
                .await
@@ -209,11 +209,14 @@ pub async fn merge_pr(
        return Err(AppError::BadRequest(format!("PR is already {}", pr.status)));
    }

+    // Shed 503 + Retry-After on an exhausted write-lock POOL instead of a generic
+    // git 500 (#173 F1). Merging holds no admission permit, so it reaches the pool
+    // unthrottled; reuse the push handler's mapping so the two cannot drift.
    let guard = state
        .repo_store
        .acquire_write(&record.owner_did, &record.name)
        .await
-        .map_err(|e| AppError::Git(e.to_string()))?;
+        .map_err(|e| crate::api::repos::acquire_write_app_error(&e, &name))?;
    let disk_path = guard.path().to_path_buf();
    let merger_did = auth.0;
    let merge_result = store::merge_branch(
@@ -424,3 +427,116 @@ pub async fn list_comments(
    let comments = state.db.list_pr_comments(&pr.id).await?;
    Ok(Json(serde_json::json!({ "comments": comments })))
 }
+
+/// #173 F1 follow-up: `merge_pr` reaches `acquire_write` holding NO admission permit
+/// (unlike the push handler, which is capped by the git-push semaphore), so it is one
+/// of the callers most likely to meet an exhausted write-lock POOL under load. An
+/// exhausted pool is a capacity signal, so the merge must shed 503 + Retry-After
+/// (`AppError::Overloaded`) the way the push handler does, not report the generic
+/// 500 git error that says nothing about retrying.
+#[cfg(test)]
+mod lock_pool_shed_tests {
+    use super::*;
+    use axum::response::IntoResponse;
+    use sqlx::PgPool;
+
+    fn seed_repo(owner_did: &str, name: &str) -> crate::db::RepoRecord {
+        let now = Utc::now();
+        crate::db::RepoRecord {
+            id: Uuid::new_v4().to_string(),
+            name: name.to_string(),
+            owner_did: owner_did.to_string(),
+            description: None,
+            is_public: true,
+            default_branch: "main".to_string(),
+            created_at: now,
+            updated_at: now,
+            disk_path: format!("/tmp/{name}"),
+            forked_from: None,
+            machine_id: None,
+        }
+    }
+
+    /// RED-before/GREEN-after for `merge_pr`. Both directions: the shed while the only
+    /// lock-pool connection is held by a guard on a DIFFERENT repo (so this is pool
+    /// capacity, not advisory-lock contention on this repo), and the must-not case
+    /// once that connection is back.
+    #[sqlx::test]
+    async fn merge_pr_lock_pool_exhaustion_sheds_503_not_500(pool: PgPool) {
+        let owner = "did:key:zMERGELOCKPOOLOWNERAAAAAAAAAAAAAAAAAAAAA";
+        let mut state = crate::test_support::test_state(pool.clone()).await;
+        // One lock-pool connection with a short checkout timeout, so a single held
+        // guard exhausts it promptly rather than at the pool default.
+        state.repo_store = crate::git::repo_store::RepoStore::new(
+            std::path::PathBuf::from("/tmp/gitlawb-pulls-lockpool"),
+            None,
+            crate::git::repo_store::build_lock_pool(&pool, 1, std::time::Duration::from_secs(1)),
+        );
+
+        let repo = seed_repo(owner, "lp-merge");
+        let repo_id = repo.id.clone();
+        state.db.create_repo(&repo).await.expect("seed repo");
+        let now = Utc::now().to_rfc3339();
+        state
+            .db
+            .create_pr(&PullRequest {
+                id: Uuid::new_v4().to_string(),
+                repo_id: repo_id.clone(),
+                number: 1,
+                title: "lp".to_string(),
+                body: None,
+                author_did: owner.to_string(),
+                source_branch: "feature".to_string(),
+                target_branch: "main".to_string(),
+                status: "open".to_string(),
+                merged_by_did: None,
+                merged_at: None,
+                created_at: now.clone(),
+                updated_at: now,
+            })
+            .await
+            .expect("seed open PR");
+
+        let held = state
+            .repo_store
+            .acquire_write(owner, "other-repo")
+            .await
+            .expect("the first write takes the only lock-pool connection");
+
+        let shed = merge_pr(
+            State(state.clone()),
+            Extension(AuthenticatedDid(owner.to_string())),
+            Path((owner.to_string(), "lp-merge".to_string(), 1)),
+        )
+        .await;
+        let err = shed.expect_err("an exhausted lock pool must fail the call");
+        let resp = err.into_response();
+        assert_eq!(
+            resp.status(),
+            StatusCode::SERVICE_UNAVAILABLE,
+            "merge_pr: an exhausted write-lock pool must shed 503, not a 500 git error"
+        );
+        assert_eq!(
+            resp.headers()
+                .get("retry-after")
+                .map(|v| v.to_str().unwrap()),
+            Some("1"),
+            "merge_pr: a capacity shed must tell the client when to retry"
+        );
+
+        // MUST-NOT: with the pool free again the merge is not shed as capacity (it
+        // fails later on the nonexistent on-disk repo, which is a git 500).
+        held.release(false).await;
+        let admitted = merge_pr(
+            State(state.clone()),
+            Extension(AuthenticatedDid(owner.to_string())),
+            Path((owner.to_string(), "lp-merge".to_string(), 1)),
+        )
+        .await;
+        assert!(
+            !matches!(admitted, Err(AppError::Overloaded(_))),
+            "with the lock pool free, merge_pr must not be shed as capacity; got {:?}",
+            admitted.err()
+        );
+    }
+}
@@ -2,14 +2,14 @@
 //!
 //! Any authenticated agent can star or unstar a repo.
 //! One agent = one star per repo (enforced by UNIQUE constraint in repo_stars).
-//! Star count is public — no auth required on GET.
+//! Star count is gated on repo read access.

 use axum::extract::{Extension, Path, State};
 use axum::http::StatusCode;
 use axum::Json;

 use crate::auth::AuthenticatedDid;
-use crate::error::{AppError, Result};
+use crate::error::Result;
 use crate::state::AppState;

 /// PUT /api/v1/repos/:owner/:repo/star
@@ -19,11 +19,8 @@ pub async fn star_repo(
    Extension(auth): Extension<AuthenticatedDid>,
    Path((owner, repo)): Path<(String, String)>,
 ) -> Result<(StatusCode, Json<serde_json::Value>)> {
-    let record = state
-        .db
-        .get_repo(&owner, &repo)
-        .await?
-        .ok_or_else(|| AppError::RepoNotFound(format!("{owner}/{repo}")))?;
+    let (record, _rules) =
+        crate::api::authorize_repo_read(&state, &owner, &repo, Some(auth.0.as_str()), "/").await?;

    let caller = &auth.0;
    let inserted = state.db.star_repo(&record.id, caller).await?;
@@ -54,11 +51,8 @@ pub async fn unstar_repo(
    Extension(auth): Extension<AuthenticatedDid>,
    Path((owner, repo)): Path<(String, String)>,
 ) -> Result<Json<serde_json::Value>> {
-    let record = state
-        .db
-        .get_repo(&owner, &repo)
-        .await?
-        .ok_or_else(|| AppError::RepoNotFound(format!("{owner}/{repo}")))?;
+    let (record, _rules) =
+        crate::api::authorize_repo_read(&state, &owner, &repo, Some(auth.0.as_str()), "/").await?;

    let caller = &auth.0;
    state.db.unstar_repo(&record.id, caller).await?;
@@ -74,16 +68,15 @@ pub async fn unstar_repo(
 }

 /// GET /api/v1/repos/:owner/:repo/star
-/// Returns star count — unauthenticated.
+/// Returns star count for callers who can read the repo.
 pub async fn get_star_status(
    State(state): State<AppState>,
    Path((owner, repo)): Path<(String, String)>,
+    auth: Option<Extension<AuthenticatedDid>>,
 ) -> Result<Json<serde_json::Value>> {
-    let record = state
-        .db
-        .get_repo(&owner, &repo)
-        .await?
-        .ok_or_else(|| AppError::RepoNotFound(format!("{owner}/{repo}")))?;
+    let caller = auth.as_ref().map(|e| e.0 .0.as_str());
+    let (record, _rules) =
+        crate::api::authorize_repo_read(&state, &owner, &repo, caller, "/").await?;

    let count = state.db.count_stars(&record.id).await?;

@@ -514,9 +514,30 @@ mod tests {
            machine_id: None,
            repo_store: crate::git::repo_store::RepoStore::for_testing(PathBuf::from("/tmp"), pool),
            rate_limiter: RateLimiter::new(100, Duration::from_secs(60)),
+            create_ip_rate_limiter: RateLimiter::new(1000, Duration::from_secs(3600)),
            push_rate_limiter: RateLimiter::new(600, Duration::from_secs(3600)),
+            ipfs_rate_limiter: RateLimiter::new(600, Duration::from_secs(3600)),
+            ipfs_work_rate_limiter: RateLimiter::new(600, Duration::from_secs(3600)),
+            ipfs_max_history_walks: crate::api::ipfs::MAX_HISTORY_WALKS_PER_REQUEST,
+            ipfs_max_legacy_probes: crate::api::ipfs::MAX_LEGACY_PROBES_PER_REQUEST,
+            ipfs_max_served_object_bytes: crate::api::ipfs::MAX_SERVED_OBJECT_BYTES,
            push_limiter_trust: crate::rate_limit::TrustedProxy::None,
+            sync_trigger_rate_limiter: RateLimiter::new(60, Duration::from_secs(3600)),
+            peer_write_rate_limiter: RateLimiter::new(600, Duration::from_secs(3600)),
            shutdown_tx: tokio::sync::watch::channel(false).0,
+            git_read_semaphore: Arc::new(tokio::sync::Semaphore::new(64)),
+            git_write_semaphore: Arc::new(tokio::sync::Semaphore::new(64)),
+            git_push_advert_semaphore: Arc::new(tokio::sync::Semaphore::new(64)),
+            git_encrypt_semaphore: Arc::new(tokio::sync::Semaphore::new(64)),
+            encrypt_inflight: crate::state::EncryptInflight::new(),
+            git_read_per_caller: crate::rate_limit::PerCallerConcurrency::with_default_max_keys(16),
+            git_push_advert_per_caller:
+                crate::rate_limit::PerCallerConcurrency::with_default_max_keys(8),
+            git_write_per_caller: crate::rate_limit::PerCallerConcurrency::with_default_max_keys(8),
+            git_ipfs_walk_semaphore: Arc::new(tokio::sync::Semaphore::new(64)),
+            git_ipfs_walk_per_caller:
+                crate::rate_limit::PerCallerConcurrency::with_default_max_keys(16),
+            git_bin: "git".to_string(),
        }
    }

@@ -52,6 +52,7 @@ pub async fn issue_ref_certificate(
        issued_at,
    };

-    state.db.insert_ref_certificate(&cert).await?;
-    Ok(cert)
+    // Persist and return the row as it exists in the database (on a
+    // conflict the existing row survives when it is newer).
+    state.db.insert_ref_certificate(&cert).await
 }
@@ -140,6 +140,20 @@ pub struct Config {
    #[arg(long, env = "GITLAWB_MAX_PACK_BYTES", default_value_t = 2_147_483_648)]
    pub max_pack_bytes: usize,

+    /// Per-client-IP rate limit for `POST /api/v1/sync/trigger`, in requests per
+    /// hour. `/sync/trigger` requires a signature and drives an O(peers) outbound
+    /// fan-out per call, so it gets a tight bucket. `0` disables. Default: 60.
+    #[arg(long, env = "GITLAWB_SYNC_TRIGGER_RATE_LIMIT", default_value_t = 60)]
+    pub sync_trigger_rate_limit: usize,
+
+    /// Per-client-IP rate limit for the peer-write routes (`/peers/announce`,
+    /// `/sync/notify`), in requests per hour. These accept unsigned requests from
+    /// known peers and run at higher frequency, so the bucket is generous. Keeping
+    /// it separate from the trigger bucket stops an unsigned notify flood from
+    /// draining the signed trigger caller's quota. `0` disables. Default: 600.
+    #[arg(long, env = "GITLAWB_PEER_WRITE_RATE_LIMIT", default_value_t = 600)]
+    pub peer_write_rate_limit: usize,
+
    /// Optional address to bind a Prometheus `/metrics` exposition endpoint on.
    /// Example: `127.0.0.1:9091`. Leave empty (default) to disable.
    /// Bind to localhost or a private interface — the metrics endpoint is
@@ -152,6 +166,287 @@ pub struct Config {
    /// in flight and exits. Default: 30s.
    #[arg(long, env = "GITLAWB_SHUTDOWN_GRACE_SECS", default_value_t = 30)]
    pub shutdown_grace_secs: u64,
+
+    /// Maximum wall-clock time a single served git operation (upload-pack /
+    /// receive-pack through `run_git_service`) may run before it is aborted and
+    /// its process group torn down, in seconds. Bounds a git that neither
+    /// finishes nor disconnects. Must be positive; set it very large to
+    /// effectively disable the bound. Default: 600s (10 min), generous for large
+    /// clones. Also bounds the ref advertisement (`info/refs`) and the withheld-blob
+    /// pack build (`upload_pack_excluding`'s pack-objects stage), which now share the
+    /// same timeout + process-group teardown (#174).
+    #[arg(
+        long,
+        env = "GITLAWB_GIT_SERVICE_TIMEOUT_SECS",
+        default_value_t = 600,
+        value_parser = clap::value_parser!(u64).range(1..)
+    )]
+    pub git_service_timeout_secs: u64,
+
+    /// Maximum wall-clock time the storage-acquisition phase of a served git
+    /// operation may run before the request is shed with a 503, in seconds. This
+    /// bounds `RepoStore::{acquire,acquire_fresh,acquire_write}` — the Tigris
+    /// HEAD/GET on a read/advert acquire and the advisory-lock retry loop (incl. a
+    /// per-iteration `pg_try_advisory_lock` that can block on a hung Postgres pool)
+    /// on a write acquire. A concurrency permit is taken BEFORE this phase, and
+    /// `git_service_timeout_secs` only starts once git spawns, so without this the
+    /// acquire phase is unbounded: a stalled backend pins the permit and drains the
+    /// pool until every later request 503s. On expiry the permit is released and a
+    /// bounded 503 + Retry-After is returned (fail-closed). Kept separate from
+    /// `git_service_timeout_secs` because acquisition and git execution are distinct
+    /// cost centers — one shared budget would let a slow acquire starve git. Must be
+    /// positive; set it very large to effectively disable the bound. Default: 30s.
+    #[arg(
+        long,
+        env = "GITLAWB_GIT_ACQUIRE_TIMEOUT_SECS",
+        default_value_t = 30,
+        value_parser = clap::value_parser!(u64).range(1..)
+    )]
+    pub git_acquire_timeout_secs: u64,
+
+    /// Maximum connections in the PostgreSQL pool. This is a cap, not a floor
+    /// (connections open lazily). Size against the database server's
+    /// max_connections, remembering admin tooling opens its own pool.
+    #[arg(
+        long,
+        env = "GITLAWB_DB_MAX_CONNECTIONS",
+        default_value_t = 20,
+        value_parser = clap::value_parser!(u32).range(1..)
+    )]
+    pub db_max_connections: u32,
+
+    /// Maximum time a request waits for a pool connection before failing with
+    /// 503, in seconds. Bounds queueing when the database is slow or down.
+    #[arg(
+        long,
+        env = "GITLAWB_DB_ACQUIRE_TIMEOUT_SECS",
+        default_value_t = 5,
+        value_parser = clap::value_parser!(u64).range(1..)
+    )]
+    pub db_acquire_timeout_secs: u64,
+
+    /// Upper bound on each startup connect-and-migrate attempt, in seconds.
+    /// Migrations wait on a cross-instance advisory lock, so this must be
+    /// generous enough for a peer instance to finish migrating; on expiry the
+    /// attempt is retried (migrations are idempotent).
+    #[arg(
+        long,
+        env = "GITLAWB_DB_CONNECT_TIMEOUT_SECS",
+        default_value_t = 60,
+        value_parser = clap::value_parser!(u64).range(1..)
+    )]
+    pub db_connect_timeout_secs: u64,
+
+    /// First retry delay when the database is unavailable at startup, in
+    /// seconds. Doubles each attempt up to --db-retry-max-secs.
+    #[arg(
+        long,
+        env = "GITLAWB_DB_RETRY_INITIAL_SECS",
+        default_value_t = 5,
+        value_parser = clap::value_parser!(u64).range(1..)
+    )]
+    pub db_retry_initial_secs: u64,
+
+    /// Ceiling on the startup retry delay, in seconds.
+    #[arg(
+        long,
+        env = "GITLAWB_DB_RETRY_MAX_SECS",
+        default_value_t = 60,
+        value_parser = clap::value_parser!(u64).range(1..)
+    )]
+    pub db_retry_max_secs: u64,
+
+    /// Maximum number of served git operations (upload-pack / receive-pack /
+    /// info-refs) allowed to run concurrently. Beyond this the node sheds the
+    /// request with a clean 503 + Retry-After instead of spawning another git
+    /// subprocess and risking PID/thread exhaustion. Portable backstop: the
+    /// compose `pids_limit` is not present on Fly, whose connection-concurrency
+    /// cap is a different axis (500 connections each fan out to git +
+    /// pack-objects + threads). Size below the process budget with headroom.
+    ///
+    /// This is the READ pool (`git_read_semaphore`): upload-pack and the UPLOAD-PACK
+    /// `info/refs` advertisement only. The authenticated push POST draws from a
+    /// separate write pool (`max_concurrent_git_pushes`) that anonymous reads can
+    /// never reach, and each read caller is additionally bounded by
+    /// `max_concurrent_reads_per_caller`, so an anonymous flood cannot shed the actual
+    /// push nor monopolize reads (#174). The anon-reachable RECEIVE-PACK `info/refs`
+    /// advertisement draws from its OWN dedicated pool (sized like the write pool but
+    /// disjoint), so an advertisement flood can never occupy a permit the
+    /// authenticated push POST needs at admission (#174).
+    ///
+    /// A permit is held for the whole op. Every git subprocess that STREAMS is
+    /// duration-bounded and reaps its process group on disconnect: upload-pack,
+    /// receive-pack, and both info/refs advertisements run under
+    /// `git_service_timeout_secs` with `process_group(0)` teardown, and the
+    /// withheld-blob (`upload_pack_excluding`) pack-objects stage plus the push-side
+    /// candidate-discovery children (`rev-list` / `cat-file`) now run under the same
+    /// bounded runner with process-group teardown, so a stuck git child no longer
+    /// holds its slot indefinitely (#174 closed the duration/cancellation gaps this
+    /// comment previously tracked).
+    ///
+    /// Default: 128. Must be between 1 and 1_048_576; the ceiling keeps the value
+    /// well under tokio's `Semaphore` permit limit so an oversized value is a
+    /// clean CLI error rather than a boot-time panic.
+    #[arg(
+        long,
+        env = "GITLAWB_MAX_CONCURRENT_GIT_OPS",
+        default_value_t = 128,
+        value_parser = clap::builder::RangedU64ValueParser::<usize>::new().range(1..=1_048_576)
+    )]
+    pub max_concurrent_git_ops: usize,
+
+    /// Maximum number of concurrent `git-receive-pack` (push) operations. The
+    /// authenticated push POST draws from this dedicated pool, separate from
+    /// `max_concurrent_git_ops` (reads), so a flood of anonymous reads cannot shed an
+    /// authenticated push at admission (#174). The anon-reachable receive-pack
+    /// `info/refs` advertisement runs in a SEPARATE pool of the same size (derived
+    /// from this knob), disjoint from this one, so an advertisement flood cannot
+    /// occupy a POST's slot either (#174). Beyond this a push sheds a clean 503 +
+    /// Retry-After.
+    ///
+    /// Default: 32. Must be between 1 and 1_048_576 (the ceiling keeps the value
+    /// under tokio's `Semaphore` permit limit so an oversized value is a clean CLI
+    /// error rather than a boot-time panic).
+    ///
+    /// CONNECTION BUDGET. A push holds a Postgres connection from the node's separate
+    /// advisory-lock pool for the whole receive-pack, and that pool is sized from this
+    /// knob (this value + 8, clamped to 64 in `main.rs`). The node's total ceiling is
+    /// therefore `db_max_connections` (default 20) + the lock pool (default 40), i.e.
+    /// 60 by default, and at most `db_max_connections` + 64. Size BOTH against the
+    /// database server's `max_connections`: `db_max_connections`' own doc predates the
+    /// lock pool and no longer covers most of the node's connections. The +8 headroom
+    /// is shared with the three non-push `acquire_write` callers (`api/issues.rs` x2,
+    /// `api/pulls.rs`). Raising this knob past the clamp does NOT buy more lock-pool
+    /// connections; pushes beyond it wait briefly and then shed a 503 + Retry-After.
+    #[arg(
+        long,
+        env = "GITLAWB_MAX_CONCURRENT_GIT_PUSHES",
+        default_value_t = 32,
+        value_parser = clap::builder::RangedU64ValueParser::<usize>::new().range(1..=1_048_576)
+    )]
+    pub max_concurrent_git_pushes: usize,
+
+    /// Maximum concurrent read operations (`upload-pack` and the upload-pack
+    /// `info/refs` advertisement) a single caller may hold at once, so one caller
+    /// cannot monopolize the `max_concurrent_git_ops` read pool (#174). Callers are
+    /// keyed on the RESOLVED SOURCE IP, never the DID — a signature does not move a
+    /// caller off this cap, so an authenticated client cannot mint DIDs to escape it.
+    /// IMPORTANT: the source-IP key is only as granular as `GITLAWB_TRUSTED_PROXY`.
+    /// Left unset (the default), a node behind an edge/NAT keys all callers on the
+    /// edge IP, so this cap collapses to a single global cap rather than per-client.
+    /// Set `GITLAWB_TRUSTED_PROXY` to key on the real client; a high-fanout caller (a
+    /// CI fleet behind one NAT) then needs the operator to raise this. Over-cap for a
+    /// caller sheds a clean 503 + Retry-After.
+    ///
+    /// Default: 16. Must be between 1 and 1_048_576.
+    #[arg(
+        long,
+        env = "GITLAWB_MAX_CONCURRENT_READS_PER_CALLER",
+        default_value_t = 16,
+        value_parser = clap::builder::RangedU64ValueParser::<usize>::new().range(1..=1_048_576)
+    )]
+    pub max_concurrent_reads_per_caller: usize,
+
+    /// Maximum number of concurrent `GET /ipfs/{cid}` requests that may run their
+    /// visibility walk at once. The publicly-reachable `/ipfs/{cid}` route runs
+    /// `allowed_blob_set_for_caller_bounded` in `spawn_blocking` — a full-history
+    /// git walk (up to `git_service_timeout_secs`) — for each candidate repo. It
+    /// draws from THIS pool, not any served-git pool: a distinct public cost center
+    /// on a distinct surface, so sharing a git pool would let anonymous /ipfs
+    /// traffic shed authenticated git ops (the auth-boundary trap). A permit is
+    /// held for the whole request (across the repo loop) so it reflects real
+    /// blocking-thread occupancy, not merely the tokio wait. Beyond this the request
+    /// sheds a clean 503 + Retry-After. Must be between 1 and 1_048_576; the ceiling
+    /// keeps the value under tokio's `Semaphore` permit limit so an oversized value
+    /// is a clean CLI error rather than a boot-time panic. Default: 32.
+    #[arg(
+        long,
+        env = "GITLAWB_MAX_CONCURRENT_IPFS_WALKS",
+        default_value_t = 32,
+        value_parser = clap::builder::RangedU64ValueParser::<usize>::new().range(1..=1_048_576)
+    )]
+    pub max_concurrent_ipfs_walks: usize,
+
+    /// Maximum concurrent `/ipfs/{cid}` walk requests a single source may hold at
+    /// once, so one source cannot monopolize `max_concurrent_ipfs_walks` (#174).
+    /// Callers are keyed on the RESOLVED SOURCE IP (`client_key`/`GITLAWB_TRUSTED_PROXY`),
+    /// never the DID — `/ipfs` accepts any `did:key` via `optional_signature` with no
+    /// admission step, so keying on the DID would let one host mint disposable DIDs to
+    /// multiply its budget. A request with no resolvable key (no trusted header, no
+    /// peer) is bounded by the global pool only, never this sub-cap. Over-cap sheds a
+    /// clean 503 + Retry-After. Must be between 1 and 1_048_576. Default: 4.
+    #[arg(
+        long,
+        env = "GITLAWB_IPFS_WALK_PER_SOURCE",
+        default_value_t = 4,
+        value_parser = clap::builder::RangedU64ValueParser::<usize>::new().range(1..=1_048_576)
+    )]
+    pub ipfs_walk_per_source: usize,
+
+    /// Per-request ceiling on the number of legacy (NULL-provenance) repos the
+    /// `/ipfs/{cid}` resolver's scan fallback will PROBE (`acquire` + `git cat-file
+    /// -t`) before giving up. The provenance path targets one repo; the legacy scan,
+    /// absent this bound, fans one anonymous request out to O(repos) subprocess spawns
+    /// and cold-cache fetches for a CID enumerable from the public pins index (#173,
+    /// INV-10). A truncated scan surfaces as a retryable 503, never a false 404. Wired
+    /// into `AppState::ipfs_max_legacy_probes` at construction; the history-walk ceiling
+    /// stays constant (`MAX_HISTORY_WALKS_PER_REQUEST`) and is NOT governed by this knob
+    /// (a smaller value would falsely 503 a provenanced request). Must be between 1 and
+    /// 1_048_576. Default: 256.
+    #[arg(
+        long,
+        env = "GITLAWB_IPFS_MAX_REPOS_WALKED",
+        default_value_t = crate::api::ipfs::MAX_LEGACY_PROBES_PER_REQUEST as usize,
+        value_parser = clap::builder::RangedU64ValueParser::<usize>::new().range(1..=1_048_576)
+    )]
+    pub ipfs_max_repos_walked: usize,
+
+    /// Per-client-IP rate limit for `GET /ipfs/{cid}`, in requests per hour. The
+    /// route is publicly reachable (`optional_signature`) and each request can drive
+    /// a full-history git walk, so it carries a per-IP flood brake in addition to the
+    /// concurrency cap above (a rate limit bounds request *rate*, the semaphore
+    /// bounds concurrent slow holds — different axes). Keyed on the resolved client
+    /// IP via `GITLAWB_TRUSTED_PROXY`. `0` disables. Default: 600.
+    ///
+    /// This is the pure once-per-request ROUTE brake. The resolver's internal
+    /// per-probe/per-walk WORK budget is a SEPARATE bucket whose capacity is DERIVED
+    /// from this value (`AppState::ipfs_work_budget`), not a knob of its own; `0` here
+    /// disables that derived bucket too.
+    #[arg(long, env = "GITLAWB_IPFS_RATE_LIMIT", default_value_t = 600)]
+    pub ipfs_rate_limit: usize,
+
+    /// Rows the legacy provider-CID repair sweep reads per batch (U4, #173).
+    ///
+    /// The sweep walks every `pinned_cids` row on the node once, repairing rows that
+    /// releases before this branch keyed on a PROVIDER CID (Kubo dag-pb / Pinata CIDv0)
+    /// instead of the raw-content resolver key. This bounds one batch, so the sweep can
+    /// never turn into a single unbounded table scan competing with request traffic.
+    /// Conservative on purpose: paired with the inter-batch delay below the default is
+    /// ~64 rows per minute, which finishes a large pin set in hours of idle background
+    /// work rather than one expensive burst. Must be between 1 and 100_000.
+    #[arg(
+        long,
+        env = "GITLAWB_PIN_REPAIR_SWEEP_BATCH",
+        default_value_t = 64,
+        value_parser = clap::builder::RangedU64ValueParser::<i64>::new().range(1..=100_000)
+    )]
+    pub pin_repair_sweep_batch: i64,
+
+    /// Seconds the legacy provider-CID repair sweep sleeps between batches (U4, #173).
+    ///
+    /// Each batch costs an indexed range scan plus, for the legacy rows in it, a
+    /// `git cat-file` per row. The delay is what keeps that off the DB's and the disk's
+    /// critical path: the sweep is repairing rows that have been unresolvable since the
+    /// upgrade, so finishing slowly is fine and finishing fast at the cost of live
+    /// traffic is not. `0` disables the pause (test and one-off operational use only).
+    /// Must be between 0 and 86_400.
+    #[arg(
+        long,
+        env = "GITLAWB_PIN_REPAIR_SWEEP_DELAY_SECS",
+        default_value_t = 60,
+        value_parser = clap::builder::RangedU64ValueParser::<u64>::new().range(0..=86_400)
+    )]
+    pub pin_repair_sweep_delay_secs: u64,
 }

 impl Config {
@@ -169,3 +464,311 @@ impl Config {
        PathBuf::from(&self.key_path)
    }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn git_service_timeout_defaults_to_600_and_rejects_zero() {
+        assert_eq!(
+            Config::parse_from(["gitlawb-node"]).git_service_timeout_secs,
+            600
+        );
+        assert_eq!(
+            Config::parse_from(["gitlawb-node", "--git-service-timeout-secs", "30"])
+                .git_service_timeout_secs,
+            30
+        );
+        // 0 is a footgun (immediate-504 on every request); clap must reject it.
+        assert!(
+            Config::try_parse_from(["gitlawb-node", "--git-service-timeout-secs", "0"]).is_err()
+        );
+    }
+
+    #[test]
+    fn max_concurrent_git_ops_defaults_and_rejects_out_of_range() {
+        assert_eq!(
+            Config::parse_from(["gitlawb-node"]).max_concurrent_git_ops,
+            128
+        );
+        assert_eq!(
+            Config::parse_from(["gitlawb-node", "--max-concurrent-git-ops", "8"])
+                .max_concurrent_git_ops,
+            8
+        );
+        // 0 permits would shed every served-git request with a 503; clap must reject it.
+        assert!(Config::try_parse_from(["gitlawb-node", "--max-concurrent-git-ops", "0"]).is_err());
+        // Above the ceiling would panic tokio's Semaphore::new at boot (permits >
+        // usize::MAX >> 3); clap must reject it as a clean CLI error instead.
+        assert!(
+            Config::try_parse_from(["gitlawb-node", "--max-concurrent-git-ops", "1048577"])
+                .is_err()
+        );
+        // The ceiling itself is accepted.
+        assert_eq!(
+            Config::parse_from(["gitlawb-node", "--max-concurrent-git-ops", "1048576"])
+                .max_concurrent_git_ops,
+            1_048_576
+        );
+    }
+
+    #[test]
+    fn max_concurrent_git_pushes_defaults_and_rejects_out_of_range() {
+        assert_eq!(
+            Config::parse_from(["gitlawb-node"]).max_concurrent_git_pushes,
+            32
+        );
+        assert_eq!(
+            Config::parse_from(["gitlawb-node", "--max-concurrent-git-pushes", "8"])
+                .max_concurrent_git_pushes,
+            8
+        );
+        // 0 permits would shed every push with a 503; clap must reject it.
+        assert!(
+            Config::try_parse_from(["gitlawb-node", "--max-concurrent-git-pushes", "0"]).is_err()
+        );
+        // Above the ceiling would panic tokio's Semaphore::new at boot; clap rejects it.
+        assert!(
+            Config::try_parse_from(["gitlawb-node", "--max-concurrent-git-pushes", "1048577"])
+                .is_err()
+        );
+        assert_eq!(
+            Config::parse_from(["gitlawb-node", "--max-concurrent-git-pushes", "1048576"])
+                .max_concurrent_git_pushes,
+            1_048_576
+        );
+    }
+
+    #[test]
+    fn max_concurrent_ipfs_walks_defaults_and_rejects_out_of_range() {
+        assert_eq!(
+            Config::parse_from(["gitlawb-node"]).max_concurrent_ipfs_walks,
+            32
+        );
+        assert_eq!(
+            Config::parse_from(["gitlawb-node", "--max-concurrent-ipfs-walks", "4"])
+                .max_concurrent_ipfs_walks,
+            4
+        );
+        // 0 permits would shed every /ipfs walk with a 503; clap must reject it.
+        assert!(
+            Config::try_parse_from(["gitlawb-node", "--max-concurrent-ipfs-walks", "0"]).is_err()
+        );
+        // Above the ceiling would panic tokio's Semaphore::new at boot; clap rejects it.
+        assert!(
+            Config::try_parse_from(["gitlawb-node", "--max-concurrent-ipfs-walks", "1048577"])
+                .is_err()
+        );
+        assert_eq!(
+            Config::parse_from(["gitlawb-node", "--max-concurrent-ipfs-walks", "1048576"])
+                .max_concurrent_ipfs_walks,
+            1_048_576
+        );
+    }
+
+    /// U4 (#173): the repair sweep's bounds are conservative by default and a batch of
+    /// 0 (a sweep that walks nothing and never terminates) is a CLI error, not a
+    /// runtime hang. The delay does accept 0, for tests and one-off operational runs.
+    #[test]
+    fn pin_repair_sweep_knobs_default_conservatively() {
+        let c = Config::parse_from(["gitlawb-node"]);
+        assert_eq!(c.pin_repair_sweep_batch, 64);
+        assert_eq!(c.pin_repair_sweep_delay_secs, 60);
+
+        assert!(Config::try_parse_from(["gitlawb-node", "--pin-repair-sweep-batch", "0"]).is_err());
+        assert!(
+            Config::try_parse_from(["gitlawb-node", "--pin-repair-sweep-batch", "100001"]).is_err()
+        );
+        assert_eq!(
+            Config::parse_from(["gitlawb-node", "--pin-repair-sweep-batch", "8"])
+                .pin_repair_sweep_batch,
+            8
+        );
+        assert_eq!(
+            Config::parse_from(["gitlawb-node", "--pin-repair-sweep-delay-secs", "0"])
+                .pin_repair_sweep_delay_secs,
+            0
+        );
+        assert!(
+            Config::try_parse_from(["gitlawb-node", "--pin-repair-sweep-delay-secs", "86401"])
+                .is_err()
+        );
+    }
+
+    #[test]
+    fn ipfs_walk_per_source_defaults_and_rejects_out_of_range() {
+        assert_eq!(Config::parse_from(["gitlawb-node"]).ipfs_walk_per_source, 4);
+        assert_eq!(
+            Config::parse_from(["gitlawb-node", "--ipfs-walk-per-source", "2"])
+                .ipfs_walk_per_source,
+            2
+        );
+        // 0 would shed every /ipfs walk from a keyed source; clap must reject it.
+        assert!(Config::try_parse_from(["gitlawb-node", "--ipfs-walk-per-source", "0"]).is_err());
+        assert!(
+            Config::try_parse_from(["gitlawb-node", "--ipfs-walk-per-source", "1048577"]).is_err()
+        );
+    }
+
+    #[test]
+    fn ipfs_max_repos_walked_defaults_and_rejects_out_of_range() {
+        assert_eq!(
+            Config::parse_from(["gitlawb-node"]).ipfs_max_repos_walked,
+            256
+        );
+        assert_eq!(
+            Config::parse_from(["gitlawb-node", "--ipfs-max-repos-walked", "8"])
+                .ipfs_max_repos_walked,
+            8
+        );
+        // 0 would walk no repos (serve nothing); clap must reject it.
+        assert!(Config::try_parse_from(["gitlawb-node", "--ipfs-max-repos-walked", "0"]).is_err());
+        assert!(
+            Config::try_parse_from(["gitlawb-node", "--ipfs-max-repos-walked", "1048577"]).is_err()
+        );
+    }
+
+    /// The `GITLAWB_IPFS_MAX_REPOS_WALKED` knob must actually reach the legacy-probe
+    /// budget it advertises (R5, KTD5): production seeds `ipfs_max_legacy_probes` from
+    /// this helper, so the knob is a no-op unless the helper reflects it. RED while the
+    /// helper returns the hardcoded `MAX_LEGACY_PROBES_PER_REQUEST` (256 regardless of
+    /// the knob), GREEN once it reads the knob.
+    #[test]
+    fn ipfs_max_repos_walked_wires_the_legacy_probe_budget() {
+        use crate::state::AppState;
+        // Knob set to 1 → a one-probe legacy budget.
+        let one = Config::parse_from(["gitlawb-node", "--ipfs-max-repos-walked", "1"]);
+        assert_eq!(
+            AppState::ipfs_legacy_probe_budget(&one),
+            1,
+            "the knob must control the legacy-probe budget, not be ignored"
+        );
+        // Unset knob preserves the shipped 256-probe behaviour.
+        let default = Config::parse_from(["gitlawb-node"]);
+        assert_eq!(
+            AppState::ipfs_legacy_probe_budget(&default),
+            256,
+            "the default knob keeps the shipped 256-probe budget"
+        );
+        assert_eq!(
+            AppState::ipfs_legacy_probe_budget(&default),
+            crate::api::ipfs::MAX_LEGACY_PROBES_PER_REQUEST,
+            "the default budget equals the constant it replaced"
+        );
+        // Ceiling guard: the knob never governs the history-walk ceiling, which must
+        // stay at MAX_PIN_SOURCES + 1 or a provenanced full source set false-503s.
+        assert!(
+            crate::api::ipfs::MAX_HISTORY_WALKS_PER_REQUEST > crate::db::MAX_PIN_SOURCES as u32,
+            "the history-walk ceiling is independent of the repos-walked knob"
+        );
+    }
+
+    /// The `/ipfs` work-budget capacity is DERIVED from the route limit (R6, KTD6), with
+    /// a hard floor of one full legacy search per window (the effective
+    /// `ipfs_max_legacy_probes`). This guards the derived default so a single
+    /// default-config deep search never self-throttles mid-scan and recreates the F6
+    /// admit-then-429 for a legitimate caller. A `RateLimiter` sized to the derived
+    /// budget must admit the whole probe budget back to back.
+    #[test]
+    fn ipfs_work_budget_derives_from_route_limit_and_clears_the_probe_floor() {
+        use crate::state::AppState;
+
+        // Default config: derived work budget = max(route 600, probe budget 256) = 600,
+        // comfortably above the 256-probe floor.
+        let default = Config::parse_from(["gitlawb-node"]);
+        let budget = AppState::ipfs_work_budget(&default);
+        assert_eq!(budget, 600, "default derives max(route 600, probe 256)");
+        assert!(
+            budget >= AppState::ipfs_legacy_probe_budget(&default) as usize,
+            "the work budget must clear one full legacy search per window"
+        );
+
+        // Tight route limit (1): the floor lifts the work budget to the probe budget
+        // (256), NOT down to 1 — a single deep search still completes its full scan.
+        let tight = Config::parse_from(["gitlawb-node", "--ipfs-rate-limit", "1"]);
+        assert_eq!(
+            AppState::ipfs_work_budget(&tight),
+            256,
+            "a tight route limit is floored at the 256-probe budget, not clamped to 1"
+        );
+
+        // Raised probe budget lifts the floor with it (the work budget tracks the
+        // effective probe budget, not the constant).
+        let raised = Config::parse_from([
+            "gitlawb-node",
+            "--ipfs-rate-limit",
+            "10",
+            "--ipfs-max-repos-walked",
+            "1000",
+        ]);
+        assert_eq!(
+            AppState::ipfs_work_budget(&raised),
+            1000,
+            "the floor tracks the operator-raised legacy-probe budget"
+        );
+
+        // 0 route limit disables the derived bucket too (a 0-capacity limiter admits all).
+        let disabled = Config::parse_from(["gitlawb-node", "--ipfs-rate-limit", "0"]);
+        assert_eq!(
+            AppState::ipfs_work_budget(&disabled),
+            0,
+            "route limit 0 disables the derived work bucket alongside the route brake"
+        );
+
+        // Behavioral floor: a limiter sized to the derived (tight-route) budget admits
+        // the whole probe budget back to back for one source, then sheds the next.
+        let budget = AppState::ipfs_work_budget(&tight);
+        let limiter =
+            crate::rate_limit::RateLimiter::new(budget, std::time::Duration::from_secs(3600));
+        let rt = tokio::runtime::Builder::new_current_thread()
+            .enable_all()
+            .build()
+            .unwrap();
+        rt.block_on(async {
+            for i in 0..budget {
+                assert!(
+                    limiter.check("1.2.3.4").await,
+                    "probe {i} of one full default-config scan must be admitted (no mid-scan throttle)"
+                );
+            }
+            assert!(
+                !limiter.check("1.2.3.4").await,
+                "the probe past the derived budget is shed"
+            );
+        });
+    }
+
+    #[test]
+    fn max_concurrent_reads_per_caller_defaults_and_rejects_out_of_range() {
+        assert_eq!(
+            Config::parse_from(["gitlawb-node"]).max_concurrent_reads_per_caller,
+            16
+        );
+        assert_eq!(
+            Config::parse_from(["gitlawb-node", "--max-concurrent-reads-per-caller", "4"])
+                .max_concurrent_reads_per_caller,
+            4
+        );
+        // 0 would shed every read from a keyed caller; clap must reject it.
+        assert!(
+            Config::try_parse_from(["gitlawb-node", "--max-concurrent-reads-per-caller", "0"])
+                .is_err()
+        );
+        assert!(Config::try_parse_from([
+            "gitlawb-node",
+            "--max-concurrent-reads-per-caller",
+            "1048577"
+        ])
+        .is_err());
+        assert_eq!(
+            Config::parse_from([
+                "gitlawb-node",
+                "--max-concurrent-reads-per-caller",
+                "1048576"
+            ])
+            .max_concurrent_reads_per_caller,
+            1_048_576
+        );
+    }
+}
@@ -38,14 +38,57 @@ pub enum AppError {
    #[error("too many requests: {0}")]
    TooManyRequests(String),

+    #[error("incomplete: {0}")]
+    Incomplete(String),
+
+    #[error("search incomplete: {0}")]
+    SearchIncomplete(String),
+
    #[error("git error: {0}")]
    Git(String),

+    #[error("git service timed out: {0}")]
+    Timeout(String),
+
+    #[error("server overloaded: {0}")]
+    Overloaded(String),
+
    #[error("database error: {0}")]
    Db(#[from] sqlx::Error),

    #[error("internal error: {0}")]
-    Internal(#[from] anyhow::Error),
+    Internal(anyhow::Error),
+}
+
+/// Shared error code/message for "the database is unreachable", also used by
+/// the degraded startup server (main.rs) and the readiness probe (server.rs)
+/// so clients see one vocabulary for the condition.
+pub const DB_UNAVAILABLE_CODE: &str = "db_unavailable";
+pub const DB_UNAVAILABLE_MESSAGE: &str = "database is temporarily unavailable";
+
+/// Connection-level sqlx failures that mean the database is unreachable right
+/// now (retryable, 503), as opposed to server-reported query errors.
+fn db_unavailable(e: &sqlx::Error) -> bool {
+    matches!(
+        e,
+        sqlx::Error::PoolTimedOut
+            | sqlx::Error::PoolClosed
+            | sqlx::Error::Io(_)
+            | sqlx::Error::Tls(_)
+    )
+}
+
+/// The db layer returns `anyhow::Result`, so sqlx errors reach handlers inside
+/// anyhow chains. Downcast them back out so the status mapping below can see
+/// them — without this, every database outage surfaces as a 500 instead of a
+/// 503. anyhow preserves downcastability through `.context()` layers.
+impl From<anyhow::Error> for AppError {
+    fn from(err: anyhow::Error) -> Self {
+        match err.downcast::<sqlx::Error>() {
+            Ok(sql) => AppError::Db(sql),
+            Err(err) => AppError::Internal(err),
+        }
+    }
 }

 impl IntoResponse for AppError {
@@ -98,7 +141,33 @@ impl IntoResponse for AppError {
            AppError::TooManyRequests(msg) => {
                (StatusCode::TOO_MANY_REQUESTS, "rate_limited", msg.clone())
            }
+            AppError::Incomplete(msg) => {
+                (StatusCode::UNPROCESSABLE_ENTITY, "incomplete", msg.clone())
+            }
+            // A bounded search that could not complete (the CID resolver hit its
+            // legacy-probe or walk ceiling), distinct from the 404 that asserts a
+            // definitive not-found: absence was NOT proven, so the caller should
+            // retry rather than treat it as gone (#173, F2). 503, retryable.
+            AppError::SearchIncomplete(msg) => (
+                StatusCode::SERVICE_UNAVAILABLE,
+                "search_incomplete",
+                msg.clone(),
+            ),
            AppError::Git(msg) => (StatusCode::INTERNAL_SERVER_ERROR, "git_error", msg.clone()),
+            // 504, distinct from the 500 git_error and from the read-gate's 404 /
+            // the auth 401, so the client can tell a deadline from a failure.
+            AppError::Timeout(msg) => (StatusCode::GATEWAY_TIMEOUT, "git_timeout", msg.clone()),
+            AppError::Db(e) if db_unavailable(e) => (
+                StatusCode::SERVICE_UNAVAILABLE,
+                DB_UNAVAILABLE_CODE,
+                DB_UNAVAILABLE_MESSAGE.into(),
+            ),
+            // 503 with a Retry-After (attached after this match — the shared tail
+            // can't carry per-variant headers). This is the single place Overloaded
+            // becomes a response, so it can never ship a 503 without the retry hint.
+            AppError::Overloaded(msg) => {
+                (StatusCode::SERVICE_UNAVAILABLE, "overloaded", msg.clone())
+            }
            AppError::Db(e) => (StatusCode::INTERNAL_SERVER_ERROR, "db_error", e.to_string()),
            AppError::Internal(e) => (
                StatusCode::INTERNAL_SERVER_ERROR,
@@ -112,8 +181,50 @@ impl IntoResponse for AppError {
            "message": message,
        }));

-        (status, body).into_response()
+        let mut resp = (status, body).into_response();
+        // Both retryable 503s advertise when to retry: Overloaded (capacity shed) and
+        // SearchIncomplete (a bounded CID search cut short by a cap — retry may complete
+        // it). They ride the shared tail above for body/status, so the header is attached
+        // here rather than in bespoke early returns, keeping each variant handled once.
+        if matches!(
+            self,
+            AppError::Overloaded(_) | AppError::SearchIncomplete(_)
+        ) {
+            resp.headers_mut().insert(
+                axum::http::header::RETRY_AFTER,
+                axum::http::HeaderValue::from_static("1"),
+            );
+        }
+        resp
    }
 }

 pub type Result<T> = std::result::Result<T, AppError>;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn timeout_maps_to_504_distinct_from_git_500() {
+        assert_eq!(
+            AppError::Timeout("x".into()).into_response().status(),
+            StatusCode::GATEWAY_TIMEOUT
+        );
+        // Guard against a swap with the generic git failure (500).
+        assert_eq!(
+            AppError::Git("x".into()).into_response().status(),
+            StatusCode::INTERNAL_SERVER_ERROR
+        );
+    }
+
+    #[test]
+    fn overloaded_maps_to_503_with_retry_after() {
+        let resp = AppError::Overloaded("x".into()).into_response();
+        assert_eq!(resp.status(), StatusCode::SERVICE_UNAVAILABLE);
+        assert_eq!(
+            resp.headers().get("retry-after").unwrap().to_str().unwrap(),
+            "1"
+        );
+    }
+}
@@ -29,9 +29,9 @@

 use std::collections::HashSet;
 use std::path::{Path, PathBuf};
-use std::process::Command;
+use std::time::{Duration, Instant};

-use anyhow::{bail, Context, Result};
+use anyhow::Result;

 /// Env var that forces the push path to always full-scan, bypassing the delta
 /// optimization (KTD7 kill-switch). Reuses the already-tested fallback branch
@@ -64,11 +64,21 @@ pub enum PinCandidates {
 /// Fail-closed: any condition where the introduced set cannot be safely
 /// determined returns [`PinCandidates::FullScanRequired`] rather than a partial
 /// set, so the caller full-scans instead of silently under-pinning.
-pub fn resolve_push_delta(repo_path: &Path, new_tips: &[&str], old_tips: &[&str]) -> PinCandidates {
-    // KTD7 kill-switch: force the (already-tested) full-scan fallback. The env
-    // read is split out from the pure logic so the resolver stays unit-testable
-    // without touching process-global state.
-    resolve_push_delta_inner(repo_path, new_tips, old_tips, force_full_scan())
+pub fn resolve_push_delta(
+    repo_path: &Path,
+    new_tips: &[&str],
+    old_tips: &[&str],
+    git_bin: &str,
+    deadline: Instant,
+) -> PinCandidates {
+    resolve_push_delta_inner(
+        repo_path,
+        new_tips,
+        old_tips,
+        force_full_scan(),
+        git_bin,
+        deadline,
+    )
 }

 /// Whether the force-full-scan kill-switch env var is set.
@@ -83,6 +93,8 @@ fn resolve_push_delta_inner(
    new_tips: &[&str],
    old_tips: &[&str],
    force_full_scan: bool,
+    git_bin: &str,
+    deadline: Instant,
 ) -> PinCandidates {
    if force_full_scan {
        tracing::debug!("{FORCE_FULL_SCAN_ENV} set — forcing full scan");
@@ -102,7 +114,7 @@ fn resolve_push_delta_inner(
    // commit). Bare `cat-file -t` returns `tag` for an annotated tag, and
    // `for-each-ref %(*objecttype)` peels only one level — neither is correct.
    for tip in new_tips {
-        match peeled_object_type(repo_path, tip) {
+        match peeled_object_type(repo_path, tip, git_bin, deadline) {
            Some(t) if t == "commit" => {}
            other => {
                tracing::debug!(
@@ -115,7 +127,7 @@ fn resolve_push_delta_inner(
        }
    }

-    match rev_list_delta(repo_path, new_tips, old_tips) {
+    match rev_list_delta(repo_path, new_tips, old_tips, git_bin, deadline) {
        Ok(oids) => PinCandidates::Delta(oids),
        Err(e) => {
            tracing::debug!(err = %e, "push-delta rev-list failed — forcing full scan");
@@ -126,41 +138,43 @@ fn resolve_push_delta_inner(

 /// Return the fully-peeled object type of `sha` (e.g. `commit`, `tree`,
 /// `blob`), or `None` if the object is missing/unpeelable or git errored.
-fn peeled_object_type(repo_path: &Path, sha: &str) -> Option<String> {
-    let output = Command::new("git")
-        .args(["cat-file", "-t", &format!("{sha}^{{}}")])
-        .current_dir(repo_path)
-        .output()
-        .ok()?;
-    if !output.status.success() {
-        return None;
-    }
-    Some(String::from_utf8_lossy(&output.stdout).trim().to_string())
+fn peeled_object_type(
+    repo_path: &Path,
+    sha: &str,
+    git_bin: &str,
+    deadline: Instant,
+) -> Option<String> {
+    let peel = format!("{sha}^{{}}");
+    let out = crate::git::visibility_pack::run_bounded_git(
+        git_bin,
+        &["cat-file", "-t", &peel],
+        repo_path,
+        b"",
+        deadline,
+    )
+    .ok()?;
+    Some(String::from_utf8_lossy(&out).trim().to_string())
 }

 /// Run `git rev-list --objects --no-object-names <new> --not <old>` and return
 /// the bare OID set. Decides on `status.success()` *before* parsing stdout, so
 /// a walk that prints a valid prefix then errors mid-walk is discarded.
-fn rev_list_delta(repo_path: &Path, new_tips: &[&str], old_tips: &[&str]) -> Result<Vec<String>> {
+fn rev_list_delta(
+    repo_path: &Path,
+    new_tips: &[&str],
+    old_tips: &[&str],
+    git_bin: &str,
+    deadline: Instant,
+) -> Result<Vec<String>> {
    let mut args: Vec<&str> = vec!["rev-list", "--objects", "--no-object-names"];
    args.extend_from_slice(new_tips);
    if !old_tips.is_empty() {
        args.push("--not");
        args.extend_from_slice(old_tips);
    }
-
-    let output = Command::new("git")
-        .args(&args)
-        .current_dir(repo_path)
-        .output()
-        .context("failed to run git rev-list for push delta")?;
-
-    if !output.status.success() {
-        let stderr = String::from_utf8_lossy(&output.stderr);
-        bail!("git rev-list failed: {stderr}");
-    }
-
-    let stdout = String::from_utf8_lossy(&output.stdout);
+    let out =
+        crate::git::visibility_pack::run_bounded_git(git_bin, &args, repo_path, b"", deadline)?;
+    let stdout = String::from_utf8_lossy(&out);
    Ok(stdout
        .lines()
        .map(|l| l.trim().to_string())
@@ -175,23 +189,19 @@ fn rev_list_delta(repo_path: &Path, new_tips: &[&str], old_tips: &[&str]) -> Res
 /// reconciliation sweep relies on. It returns *all* objects (including
 /// unreachable/dangling ones), which is what the sweep needs to catch
 /// stragglers — do not swap it for a reachability walk.
-pub fn list_all_objects(repo_path: &Path) -> Result<Vec<String>> {
-    let output = Command::new("git")
-        .args([
+pub fn list_all_objects(repo_path: &Path, git_bin: &str, deadline: Instant) -> Result<Vec<String>> {
+    let out = crate::git::visibility_pack::run_bounded_git(
+        git_bin,
+        &[
            "cat-file",
            "--batch-all-objects",
            "--batch-check=%(objectname)",
-        ])
-        .current_dir(repo_path)
-        .output()
-        .context("failed to run git cat-file")?;
-
-    if !output.status.success() {
-        let stderr = String::from_utf8_lossy(&output.stderr);
-        bail!("git cat-file failed: {stderr}");
-    }
-
-    let stdout = String::from_utf8_lossy(&output.stdout);
+        ],
+        repo_path,
+        b"",
+        deadline,
+    )?;
+    let stdout = String::from_utf8_lossy(&out);
    Ok(stdout
        .lines()
        .map(|l| l.trim().to_string())
@@ -203,23 +213,23 @@ pub fn list_all_objects(repo_path: &Path) -> Result<Vec<String>> {
 /// `--batch-check='%(objectname) %(objecttype)'`. The pin path's fail-closed
 /// filter needs to tell blobs (content, withholdable) from commits/trees
 /// (structural, never withheld) without typing the candidate list itself.
-pub fn list_all_objects_with_type(repo_path: &Path) -> Result<Vec<(String, String)>> {
-    let output = Command::new("git")
-        .args([
+pub fn list_all_objects_with_type(
+    repo_path: &Path,
+    git_bin: &str,
+    deadline: Instant,
+) -> Result<Vec<(String, String)>> {
+    let out = crate::git::visibility_pack::run_bounded_git(
+        git_bin,
+        &[
            "cat-file",
            "--batch-all-objects",
            "--batch-check=%(objectname) %(objecttype)",
-        ])
-        .current_dir(repo_path)
-        .output()
-        .context("failed to run git cat-file")?;
-
-    if !output.status.success() {
-        let stderr = String::from_utf8_lossy(&output.stderr);
-        bail!("git cat-file failed: {stderr}");
-    }
-
-    let stdout = String::from_utf8_lossy(&output.stdout);
+        ],
+        repo_path,
+        b"",
+        deadline,
+    )?;
+    let stdout = String::from_utf8_lossy(&out);
    Ok(stdout
        .lines()
        .filter_map(|l| {
@@ -235,8 +245,12 @@ pub fn list_all_objects_with_type(repo_path: &Path) -> Result<Vec<(String, Strin
 /// fail-closed pin filter drops any candidate blob absent from the reachable,
 /// visibility-allowed set; a dangling private blob is in this set but not the
 /// allowed set, so it never replicates (#99).
-pub fn all_blob_oids(repo_path: &Path) -> Result<HashSet<String>> {
-    Ok(list_all_objects_with_type(repo_path)?
+pub fn all_blob_oids(
+    repo_path: &Path,
+    git_bin: &str,
+    deadline: Instant,
+) -> Result<HashSet<String>> {
+    Ok(list_all_objects_with_type(repo_path, git_bin, deadline)?
        .into_iter()
        .filter(|(_, ty)| ty == "blob")
        .map(|(oid, _)| oid)
@@ -272,18 +286,22 @@ pub async fn resolve_candidates_for_push(
    repo_path: PathBuf,
    new_tips: Vec<String>,
    old_tips: Vec<String>,
+    git_bin: String,
+    timeout: Duration,
 ) -> PinCandidateSet {
    tokio::task::spawn_blocking(move || {
+        // ONE shared deadline for the whole scan, per jatmn ("the same deadline").
+        let deadline = Instant::now() + timeout;
        let new_refs: Vec<&str> = new_tips.iter().map(String::as_str).collect();
        let old_refs: Vec<&str> = old_tips.iter().map(String::as_str).collect();
-        match resolve_push_delta(&repo_path, &new_refs, &old_refs) {
+        match resolve_push_delta(&repo_path, &new_refs, &old_refs, &git_bin, deadline) {
            PinCandidates::Delta(objs) => {
                tracing::info!(delta = objs.len(), repo = %repo_path.display(), "pin candidate set from push delta");
                PinCandidateSet { candidates: objs, full_scan: false }
            }
            PinCandidates::FullScanRequired => {
                tracing::warn!(repo = %repo_path.display(), "pin delta unavailable (non-commit tip, git error, or force-full-scan) — full-scan fallback");
-                match list_all_objects(&repo_path) {
+                match list_all_objects(&repo_path, &git_bin, deadline) {
                    Ok(objs) => PinCandidateSet { candidates: objs, full_scan: true },
                    Err(e) => {
                        tracing::warn!(repo = %repo_path.display(), err = %e, "full-scan fallback failed; pinning nothing this push (reconciliation sweep backstops)");
@@ -304,8 +322,13 @@ pub async fn resolve_candidates_for_push(
 mod tests {
    use super::*;
    use std::collections::HashSet;
+    use std::process::Command;
    use tempfile::TempDir;

+    fn td() -> std::time::Instant {
+        std::time::Instant::now() + std::time::Duration::from_secs(600)
+    }
+
    /// Minimal git helper for building test repos.
    struct Repo {
        _td: TempDir,
@@ -363,9 +386,10 @@ mod tests {
        let repo = Repo::new();
        let c1 = repo.commit_file("a.txt", "one\n");
        let c2 = repo.commit_file("b.txt", "two\n");
-        let got: HashSet<String> = delta(resolve_push_delta(&repo.path, &[&c2], &[&c1]))
-            .into_iter()
-            .collect();
+        let got: HashSet<String> =
+            delta(resolve_push_delta(&repo.path, &[&c2], &[&c1], "git", td()))
+                .into_iter()
+                .collect();
        // The new blob b.txt and commit c2 are in the delta; the old blob a.txt
        // and commit c1 are not.
        let new_blob = repo.rev("HEAD:b.txt");
@@ -383,7 +407,7 @@ mod tests {
        // genuinely new objects, never fewer.
        let repo = Repo::new();
        let c1 = repo.commit_file("a.txt", "one\n");
-        let got: HashSet<String> = delta(resolve_push_delta(&repo.path, &[&c1], &[]))
+        let got: HashSet<String> = delta(resolve_push_delta(&repo.path, &[&c1], &[], "git", td()))
            .into_iter()
            .collect();
        assert!(got.contains(&c1));
@@ -399,9 +423,15 @@ mod tests {
        // Rewrite history: reset to base, commit a different file.
        repo.git(&["reset", "-q", "--hard", &base]);
        let new_tip = repo.commit_file("c.txt", "three\n");
-        let got: HashSet<String> = delta(resolve_push_delta(&repo.path, &[&new_tip], &[&old_tip]))
-            .into_iter()
-            .collect();
+        let got: HashSet<String> = delta(resolve_push_delta(
+            &repo.path,
+            &[&new_tip],
+            &[&old_tip],
+            "git",
+            td(),
+        ))
+        .into_iter()
+        .collect();
        assert!(got.contains(&new_tip), "new tip in delta");
        assert!(got.contains(&repo.rev(&format!("{new_tip}:c.txt"))));
        // No error; force-push computes new-minus-old cleanly.
@@ -413,7 +443,7 @@ mod tests {
        repo.commit_file("a.txt", "one\n");
        // All updates were deletions => new_tips empty after the caller strips zeros.
        assert_eq!(
-            resolve_push_delta(&repo.path, &[], &[ZERO]),
+            resolve_push_delta(&repo.path, &[], &[ZERO], "git", td()),
            PinCandidates::Delta(Vec::new())
        );
    }
@@ -424,7 +454,7 @@ mod tests {
        repo.commit_file("a.txt", "one\n");
        let blob = repo.rev("HEAD:a.txt");
        assert_eq!(
-            resolve_push_delta(&repo.path, &[&blob], &[]),
+            resolve_push_delta(&repo.path, &[&blob], &[], "git", td()),
            PinCandidates::FullScanRequired,
            "a blob tip must force full scan (rev-list would exit 0 and walk it)"
        );
@@ -436,7 +466,7 @@ mod tests {
        repo.commit_file("a.txt", "one\n");
        let tree = repo.rev("HEAD^{tree}");
        assert_eq!(
-            resolve_push_delta(&repo.path, &[&tree], &[]),
+            resolve_push_delta(&repo.path, &[&tree], &[], "git", td()),
            PinCandidates::FullScanRequired
        );
    }
@@ -449,7 +479,7 @@ mod tests {
        repo.git(&["tag", "-a", "treetag", "-m", "x", &tree]);
        let tag = repo.rev("treetag");
        assert_eq!(
-            resolve_push_delta(&repo.path, &[&tag], &[]),
+            resolve_push_delta(&repo.path, &[&tag], &[], "git", td()),
            PinCandidates::FullScanRequired,
            "annotated tag peeling to a tree must force full scan"
        );
@@ -465,7 +495,7 @@ mod tests {
        repo.git(&["tag", "-a", "t2", "-m", "x", &t1]);
        let t2 = repo.rev("t2");
        assert_eq!(
-            resolve_push_delta(&repo.path, &[&t2], &[]),
+            resolve_push_delta(&repo.path, &[&t2], &[], "git", td()),
            PinCandidates::FullScanRequired
        );
    }
@@ -480,7 +510,7 @@ mod tests {
        let c1 = repo.commit_file("a.txt", "one\n");
        repo.git(&["tag", "-a", "rel", "-m", "release", &c1]);
        let tag = repo.rev("rel");
-        let got: HashSet<String> = delta(resolve_push_delta(&repo.path, &[&tag], &[]))
+        let got: HashSet<String> = delta(resolve_push_delta(&repo.path, &[&tag], &[], "git", td()))
            .into_iter()
            .collect();
        assert!(
@@ -501,7 +531,7 @@ mod tests {
        let t1 = repo.rev("t1");
        repo.git(&["tag", "-a", "t2", "-m", "x", &t1]);
        let t2 = repo.rev("t2");
-        let got: HashSet<String> = delta(resolve_push_delta(&repo.path, &[&t2], &[]))
+        let got: HashSet<String> = delta(resolve_push_delta(&repo.path, &[&t2], &[], "git", td()))
            .into_iter()
            .collect();
        assert!(
@@ -516,9 +546,14 @@ mod tests {
        let repo = Repo::new();
        let c1 = repo.commit_file("a.txt", "one\n");
        let c2 = repo.commit_file("b.txt", "two\n");
-        let set =
-            resolve_candidates_for_push(repo.path.clone(), vec![c2.clone()], vec![c1.clone()])
-                .await;
+        let set = resolve_candidates_for_push(
+            repo.path.clone(),
+            vec![c2.clone()],
+            vec![c1.clone()],
+            "git".to_string(),
+            std::time::Duration::from_secs(600),
+        )
+        .await;
        assert!(!set.full_scan, "happy-path delta is not a full scan");
        let got: HashSet<String> = set.candidates.into_iter().collect();
        let new_blob = repo.rev("HEAD:b.txt");
@@ -536,8 +571,18 @@ mod tests {
        let repo = Repo::new();
        repo.commit_file("a.txt", "one\n");
        let blob = repo.rev("HEAD:a.txt");
-        let all: HashSet<String> = list_all_objects(&repo.path).unwrap().into_iter().collect();
-        let set = resolve_candidates_for_push(repo.path.clone(), vec![blob], vec![]).await;
+        let all: HashSet<String> = list_all_objects(&repo.path, "git", td())
+            .unwrap()
+            .into_iter()
+            .collect();
+        let set = resolve_candidates_for_push(
+            repo.path.clone(),
+            vec![blob],
+            vec![],
+            "git".to_string(),
+            std::time::Duration::from_secs(600),
+        )
+        .await;
        assert!(set.full_scan, "non-commit tip is signalled as a full scan");
        let got: HashSet<String> = set.candidates.into_iter().collect();
        assert_eq!(got, all, "non-commit tip falls back to full repo scan");
@@ -549,7 +594,7 @@ mod tests {
        repo.commit_file("a.txt", "one\n");
        let bogus = "deadbeefdeadbeefdeadbeefdeadbeefdeadbeef";
        assert_eq!(
-            resolve_push_delta(&repo.path, &[bogus], &[]),
+            resolve_push_delta(&repo.path, &[bogus], &[], "git", td()),
            PinCandidates::FullScanRequired,
            "a missing/corrupt tip OID must force full scan"
        );
@@ -564,7 +609,7 @@ mod tests {
        let c1 = repo.commit_file("a.txt", "one\n");
        let c2 = repo.commit_file("b.txt", "two\n");
        let old_tree = repo.rev(&format!("{c1}^{{tree}}"));
-        let result = resolve_push_delta(&repo.path, &[&c2], &[&old_tree]);
+        let result = resolve_push_delta(&repo.path, &[&c2], &[&old_tree], "git", td());
        match result {
            PinCandidates::FullScanRequired => {} // safe: caller full-scans
            PinCandidates::Delta(objs) => {
@@ -583,10 +628,15 @@ mod tests {
        // branch2 from base advances independently
        repo.git(&["checkout", "-q", "-b", "branch2", &base]);
        let b2 = repo.commit_file("c.txt", "three\n");
-        let got: HashSet<String> =
-            delta(resolve_push_delta(&repo.path, &[&b1, &b2], &[&base, &base]))
-                .into_iter()
-                .collect();
+        let got: HashSet<String> = delta(resolve_push_delta(
+            &repo.path,
+            &[&b1, &b2],
+            &[&base, &base],
+            "git",
+            td(),
+        ))
+        .into_iter()
+        .collect();
        assert!(got.contains(&b1), "branch1 new commit");
        assert!(got.contains(&b2), "branch2 new commit");
    }
@@ -595,7 +645,7 @@ mod tests {
    fn empty_repo_no_tips_yields_empty_delta() {
        let repo = Repo::new();
        assert_eq!(
-            resolve_push_delta(&repo.path, &[], &[]),
+            resolve_push_delta(&repo.path, &[], &[], "git", td()),
            PinCandidates::Delta(Vec::new())
        );
    }
@@ -609,12 +659,12 @@ mod tests {
        let repo = Repo::new();
        let c1 = repo.commit_file("a.txt", "one\n");
        assert_eq!(
-            resolve_push_delta_inner(&repo.path, &[&c1], &[], true),
+            resolve_push_delta_inner(&repo.path, &[&c1], &[], true, "git", td()),
            PinCandidates::FullScanRequired
        );
        // And with the flag off, the same push yields a Delta.
        assert!(matches!(
-            resolve_push_delta_inner(&repo.path, &[&c1], &[], false),
+            resolve_push_delta_inner(&repo.path, &[&c1], &[], false, "git", td()),
            PinCandidates::Delta(_)
        ));
    }
@@ -624,7 +674,7 @@ mod tests {
        let repo = Repo::new();
        repo.commit_file("a.txt", "one\n");
        repo.commit_file("b.txt", "two\n");
-        let all = list_all_objects(&repo.path).unwrap();
+        let all = list_all_objects(&repo.path, "git", td()).unwrap();
        // 2 commits + 2 trees + 2 blobs = 6 objects.
        assert_eq!(all.len(), 6, "got: {all:?}");
    }
@@ -642,7 +692,7 @@ mod tests {
        std::fs::write(repo.path.join("orphan.bin"), b"dangling\n").unwrap();
        let dangling = repo.git(&["hash-object", "-w", "orphan.bin"]);

-        let blobs = all_blob_oids(&repo.path).unwrap();
+        let blobs = all_blob_oids(&repo.path, "git", td()).unwrap();
        assert!(blobs.contains(&reachable_blob), "reachable blob present");
        assert!(
            blobs.contains(&dangling),
@@ -652,7 +702,7 @@ mod tests {
        assert!(!blobs.contains(&tree), "tree is not a blob");

        // The typed lister tags each object; spot-check the dangling blob's type.
-        let typed = list_all_objects_with_type(&repo.path).unwrap();
+        let typed = list_all_objects_with_type(&repo.path, "git", td()).unwrap();
        assert!(
            typed
                .iter()
@@ -660,4 +710,96 @@ mod tests {
            "dangling object is typed as a blob"
        );
    }
+
+    #[cfg(unix)]
+    #[test]
+    fn list_all_objects_times_out_on_a_hung_git_instead_of_blocking() {
+        use std::os::unix::fs::PermissionsExt;
+        use std::time::{Duration, Instant};
+        let dir = tempfile::TempDir::new().unwrap();
+        // Fake git: hang on cat-file (bounded to 30s so a broken test can't wedge).
+        let fake = dir.path().join("fakegit");
+        std::fs::write(
+            &fake,
+            "#!/bin/sh\ncase \"$1\" in\n  cat-file) i=0; while [ $i -lt 30 ]; do sleep 1; i=$((i+1)); done ;;\n  *) : ;;\nesac\n",
+        )
+        .unwrap();
+        let mut perm = std::fs::metadata(&fake).unwrap().permissions();
+        perm.set_mode(0o755);
+        std::fs::set_permissions(&fake, perm).unwrap();
+        let git_bin = fake.to_str().unwrap().to_string();
+
+        let (tx, rx) = std::sync::mpsc::channel();
+        let path = dir.path().to_path_buf();
+        std::thread::spawn(move || {
+            let _ = tx.send(list_all_objects(
+                &path,
+                &git_bin,
+                Instant::now() + Duration::from_millis(150),
+            ));
+        });
+        let res = rx.recv_timeout(Duration::from_secs(10)).expect(
+            "list_all_objects must return within the watchdog budget, not block on a hung git",
+        );
+        assert!(
+            res.is_err(),
+            "a hung git must make list_all_objects error out, not hang"
+        );
+    }
+
+    /// #174 finding 2: the DELTA-path children — `peeled_object_type` (cat-file),
+    /// `rev_list_delta` (rev-list) — and `list_all_objects_with_type` (cat-file) are
+    /// the remaining candidate-discovery execs (the common push path). Each must
+    /// return within the watchdog budget on a hung git rather than block and pin the
+    /// write permit. Revert any one to a bare `Command::output()` and its arm blocks
+    /// past the recv budget (RED).
+    #[cfg(unix)]
+    #[test]
+    fn delta_path_exec_fns_time_out_on_a_hung_git() {
+        use std::os::unix::fs::PermissionsExt;
+        use std::time::{Duration, Instant};
+        let dir = tempfile::TempDir::new().unwrap();
+        // Fake git hangs on BOTH cat-file and rev-list (bounded 30s so a broken
+        // test can't leak a permanent orphan or wedge the suite).
+        let fake = dir.path().join("fakegit");
+        std::fs::write(
+            &fake,
+            "#!/bin/sh\ncase \"$1\" in\n  cat-file|rev-list) i=0; while [ $i -lt 30 ]; do sleep 1; i=$((i+1)); done ;;\n  *) : ;;\nesac\n",
+        )
+        .unwrap();
+        let mut perm = std::fs::metadata(&fake).unwrap().permissions();
+        perm.set_mode(0o755);
+        std::fs::set_permissions(&fake, perm).unwrap();
+        let git_bin = fake.to_str().unwrap().to_string();
+        let path = dir.path().to_path_buf();
+
+        // Run `f` on a thread and require it to RETURN (not block) within 10s.
+        fn returns_within<T: Send + 'static>(f: impl FnOnce() -> T + Send + 'static) -> T {
+            let (tx, rx) = std::sync::mpsc::channel();
+            std::thread::spawn(move || {
+                let _ = tx.send(f());
+            });
+            rx.recv_timeout(Duration::from_secs(10)).expect(
+                "a delta-path exec fn must return within the watchdog budget, not block on a hung git",
+            )
+        }
+        let dl = || Instant::now() + Duration::from_millis(150);
+        let sha = "deadbeefdeadbeefdeadbeefdeadbeefdeadbeef";
+
+        let (p, g, d) = (path.clone(), git_bin.clone(), dl());
+        assert!(
+            returns_within(move || peeled_object_type(&p, sha, &g, d)).is_none(),
+            "peeled_object_type must time out to None on a hung cat-file"
+        );
+        let (p, g, d) = (path.clone(), git_bin.clone(), dl());
+        assert!(
+            returns_within(move || rev_list_delta(&p, &[sha], &[], &g, d)).is_err(),
+            "rev_list_delta must error out on a hung rev-list"
+        );
+        let (p, g, d) = (path.clone(), git_bin.clone(), dl());
+        assert!(
+            returns_within(move || list_all_objects_with_type(&p, &g, d)).is_err(),
+            "list_all_objects_with_type must error out on a hung cat-file"
+        );
+    }
 }
@@ -11,9 +11,12 @@
 use std::collections::HashSet;
 use std::path::{Path, PathBuf};
 use std::sync::Arc;
+use std::time::Duration;

 use anyhow::{Context, Result};
-use sqlx::PgPool;
+use sqlx::pool::PoolConnection;
+use sqlx::postgres::PgPoolOptions;
+use sqlx::{PgPool, Postgres};
 use tokio::sync::Mutex;
 use tracing::{debug, info, warn};

@@ -25,30 +28,79 @@ use super::tigris::TigrisClient;
 pub struct RepoStore {
    repos_dir: PathBuf,
    tigris: Option<TigrisClient>,
-    /// Shared Postgres pool for advisory locks.
-    pool: PgPool,
+    /// Dedicated Postgres pool for repo write advisory locks, built by
+    /// `build_lock_pool` (see there for why it is separate and why it carries an
+    /// `after_release` hook). Never use this for ordinary queries.
+    lock_pool: PgPool,
    /// Tracks repos already confirmed to exist in Tigris — avoids redundant
    /// HEAD checks and background uploads for repos we've already migrated.
    migrated: Arc<Mutex<HashSet<String>>>,
+    /// Test-only stall injected at the head of `acquire_write`'s Tigris phase,
+    /// i.e. AFTER the advisory lock is taken and BEFORE the guard exists. That
+    /// window is exactly where the outer `tokio::time::timeout` in
+    /// `api/repos.rs` can drop the future (#173). `TigrisClient` takes its
+    /// endpoint from process-wide AWS env vars and has no injectable seam, so
+    /// this flag is the smallest way to hold a real `acquire_write` open in that
+    /// window and cancel it there.
+    #[cfg(test)]
+    tigris_stall: Option<std::time::Duration>,
+    /// Test-only counter of how many times a write guard from this store REACHED the
+    /// Tigris upload site in `release` (the point past the `success` check, where a
+    /// configured client would be uploaded to). It counts the decision, not a network
+    /// call: `TigrisClient` takes its endpoint from process-wide AWS env vars and has no
+    /// injectable seam, so every test runs with `tigris: None` and a counter inside the
+    /// `Some` arm could never move. Reaching the site is the property under test anyway:
+    /// an interrupted push must not publish a half-applied repo, and the disconnect path
+    /// must therefore never get here (#173 F2).
+    ///
+    /// Per store rather than a process global, so cases running in parallel do not see
+    /// each other's uploads, and an `Arc` rather than a `thread_local` because the guard
+    /// is released from a detached task on another worker thread. Same test-only counter
+    /// idiom as `ipfs_pin::note_legacy_repair_read`.
+    #[cfg(test)]
+    upload_site_reached: Arc<std::sync::atomic::AtomicUsize>,
 }

 impl RepoStore {
+    /// Derives its own lock pool from `pool`, so callers that only have the main
+    /// pool (tests, `for_testing` sites in other modules) still get the
+    /// `after_release` semantics `acquire_write` depends on.
    #[cfg(test)]
    pub fn for_testing(repos_dir: PathBuf, pool: PgPool) -> Self {
-        Self {
+        Self::new(
            repos_dir,
-            tigris: None,
-            pool,
-            migrated: Arc::new(tokio::sync::Mutex::new(std::collections::HashSet::new())),
-        }
+            None,
+            build_lock_pool(&pool, 8, Duration::from_secs(5)),
+        )
    }

-    pub fn new(repos_dir: PathBuf, tigris: Option<TigrisClient>, pool: PgPool) -> Self {
+    /// Test-only: see `tigris_stall`.
+    #[cfg(test)]
+    pub fn with_tigris_stall(mut self, stall: Duration) -> Self {
+        self.tigris_stall = Some(stall);
+        self
+    }
+
+    /// Test-only: how many write guards from this store have reached the Tigris upload
+    /// site. See [`RepoStore::upload_site_reached`].
+    #[cfg(test)]
+    pub fn tigris_upload_site_reached(&self) -> usize {
+        self.upload_site_reached
+            .load(std::sync::atomic::Ordering::SeqCst)
+    }
+
+    /// `lock_pool` must come from `build_lock_pool`; a plain pool leaks advisory
+    /// locks on cancellation.
+    pub fn new(repos_dir: PathBuf, tigris: Option<TigrisClient>, lock_pool: PgPool) -> Self {
        Self {
            repos_dir,
            tigris,
-            pool,
+            lock_pool,
            migrated: Arc::new(Mutex::new(HashSet::new())),
+            #[cfg(test)]
+            tigris_stall: None,
+            #[cfg(test)]
+            upload_site_reached: Arc::new(std::sync::atomic::AtomicUsize::new(0)),
        }
    }

@@ -157,25 +209,64 @@ impl RepoStore {
        let (owner_slug, local_path) = self.local_path(owner_did, repo_name)?;
        let lock_key = advisory_lock_key(&owner_slug, repo_name);

-        // Acquire Postgres advisory lock with retry using pg_try_advisory_lock
-        // to avoid blocking indefinitely on stale locks from crashed connections.
-        let mut acquired = false;
+        // Acquire the Postgres advisory lock with retry, using pg_try_advisory_lock so a
+        // stale lock from a crashed connection can't block us indefinitely.
+        //
+        // The connection is checked out INSIDE the loop and RETURNED before each sleep.
+        // Only the connection that actually took the lock is retained. Two constraints
+        // pull in opposite directions here, and this is what satisfies both:
+        //
+        //   * Session ownership. A session-level advisory lock belongs to the CONNECTION
+        //     that took it, so the lock and its `pg_advisory_unlock` must run on the same
+        //     one. Running them through the pool (`fetch_one(&self.pool)`) lets them land
+        //     on different connections: the unlock silently returns false and the lock
+        //     leaks, while a competing acquire that happens to draw the holding
+        //     connection re-enters the lock and two pushes to one repo run concurrently.
+        //     Hence: keep the connection that WON.
+        //   * Occupancy. Holding a connection across the ~60 one-second sleeps would let
+        //     one spinning acquire park a lock-pool connection for a minute. That is not
+        //     just a push-path concern: `api/issues.rs` and `api/pulls.rs` reach
+        //     acquire_write holding no concurrency permit at all, so a caller could park
+        //     the whole pool and starve authenticated pushes on every repo (#173 F1).
+        //     Hence: return the connection when we LOSE, before sleeping.
+        //
+        // Returning a losing connection is safe with respect to the cancellation design:
+        // `after_release` runs `pg_advisory_unlock_all()`, a no-op on a connection that
+        // took nothing, so it cannot disturb a lock held by any other connection
+        // (proven by `returning_an_unlocked_connection_does_not_clear_another_connections_lock`).
+        //
+        // Cancellation safety is unchanged: the future can only be dropped while a
+        // connection is checked out, and dropping it runs the same `after_release` hook,
+        // which clears whatever lock it had just taken (#173 U1).
+        let mut lock_conn = None;
        for attempt in 0..60 {
+            let mut conn = self.lock_pool.acquire().await.map_err(|e| {
+                anyhow::Error::new(LockPoolBusy)
+                    .context(format!("checking out a lock-pool connection: {e}"))
+            })?;
            let row: (bool,) = sqlx::query_as("SELECT pg_try_advisory_lock($1)")
                .bind(lock_key)
-                .fetch_one(&self.pool)
+                .fetch_one(&mut *conn)
                .await
                .context("trying advisory lock")?;
            if row.0 {
-                acquired = true;
+                lock_conn = Some(conn);
                break;
            }
+            // Lost the race: give the connection back so a spinning acquire occupies
+            // nothing while it waits.
+            drop(conn);
            if attempt < 59 {
                tokio::time::sleep(std::time::Duration::from_secs(1)).await;
            }
        }
-        if !acquired {
+        let Some(lock_conn) = lock_conn else {
            anyhow::bail!("could not acquire advisory lock after 60s — possible stale lock for {owner_slug}/{repo_name}");
+        };
+
+        #[cfg(test)]
+        if let Some(stall) = self.tigris_stall {
+            tokio::time::sleep(stall).await;
        }

        // Always download the latest from Tigris before writing.
@@ -202,8 +293,10 @@ impl RepoStore {
            repo_name: repo_name.to_string(),
            local_path,
            lock_key,
-            pool: self.pool.clone(),
+            lock_conn,
            tigris: self.tigris.clone(),
+            #[cfg(test)]
+            upload_site_reached: Arc::clone(&self.upload_site_reached),
        })
    }

@@ -257,42 +350,63 @@ impl RepoStore {
    ///      segment is rejected. This is the CodeQL-recognised barrier
    ///      pattern for `rust/path-injection`.
    fn local_path(&self, owner_did: &str, repo_name: &str) -> Result<(String, PathBuf)> {
-        validate_path_components(owner_did, repo_name)?;
-
        let owner_slug = owner_did.replace([':', '/'], "_");
-        let local_path = self
-            .repos_dir
-            .join(&owner_slug)
-            .join(format!("{repo_name}.git"));
-
-        if !local_path.starts_with(&self.repos_dir) {
-            anyhow::bail!(
-                "computed repo path escaped repos_dir: {}",
-                local_path.display()
-            );
-        }
-
-        // Explicit component walk — sanitisation barrier that static analysers
-        // (CodeQL `rust/path-injection`) recognise. The path must be composed
-        // entirely of Normal segments after the root prefix; any ParentDir or
-        // CurDir component is a traversal attempt.
-        for component in local_path.components() {
-            use std::path::Component;
-            match component {
-                Component::Prefix(_) | Component::RootDir | Component::Normal(_) => {}
-                Component::ParentDir => {
-                    anyhow::bail!("path contains parent-directory component");
-                }
-                Component::CurDir => {
-                    anyhow::bail!("path contains current-directory component");
-                }
-            }
-        }
-
+        let local_path = validated_repo_disk_path(&self.repos_dir, owner_did, repo_name)?;
        Ok((owner_slug, local_path))
    }
 }

+/// The three-layer validated form of `store::repo_disk_path`, with NO Tigris fetch and
+/// no `RepoStore` (#173 round 11, F3). Extracted from `RepoStore::local_path` so a
+/// second caller that must not pull a cold repo, the U4 legacy provider-CID sweep, gets
+/// the same barrier instead of the raw join. `local_path` is now a thin wrapper over
+/// this, so the two cannot drift.
+///
+/// Three-layer defence against path traversal:
+///   1. Strict allowlist on `owner_did` and `repo_name` (no `..`, slashes,
+///      null bytes, leading dots; length-bounded).
+///   2. The joined path must remain rooted at `repos_dir`.
+///   3. Every component of the joined path must be `Component::Normal`
+///      (or the prefix/root from `repos_dir`); any `ParentDir`/`CurDir`
+///      segment is rejected. This is the CodeQL-recognised barrier
+///      pattern for `rust/path-injection`.
+pub(crate) fn validated_repo_disk_path(
+    repos_dir: &Path,
+    owner_did: &str,
+    repo_name: &str,
+) -> Result<PathBuf> {
+    validate_path_components(owner_did, repo_name)?;
+
+    let owner_slug = owner_did.replace([':', '/'], "_");
+    let local_path = repos_dir.join(&owner_slug).join(format!("{repo_name}.git"));
+
+    if !local_path.starts_with(repos_dir) {
+        anyhow::bail!(
+            "computed repo path escaped repos_dir: {}",
+            local_path.display()
+        );
+    }
+
+    // Explicit component walk — sanitisation barrier that static analysers
+    // (CodeQL `rust/path-injection`) recognise. The path must be composed
+    // entirely of Normal segments after the root prefix; any ParentDir or
+    // CurDir component is a traversal attempt.
+    for component in local_path.components() {
+        use std::path::Component;
+        match component {
+            Component::Prefix(_) | Component::RootDir | Component::Normal(_) => {}
+            Component::ParentDir => {
+                anyhow::bail!("path contains parent-directory component");
+            }
+            Component::CurDir => {
+                anyhow::bail!("path contains current-directory component");
+            }
+        }
+    }
+
+    Ok(local_path)
+}
+
 /// Strict allowlist validator for `owner_did` and `repo_name`.
 ///
 /// Rejects any character that isn't explicitly safe, plus length and
@@ -347,6 +461,19 @@ fn validate_repo_name(repo_name: &str) -> Result<()> {
    Ok(())
 }

+/// Error marker for "no lock-pool connection was available in time".
+///
+/// Carried through the `anyhow` chain (like [`smart_http::GitServiceTimeout`]) so the
+/// HTTP handler can `downcast_ref` it and shed a 503 + Retry-After instead of the
+/// generic 500 a git error maps to: an exhausted lock pool is a CAPACITY signal, and
+/// telling the client to retry shortly is the same shed semantics the surrounding
+/// admission code already uses (#173 F1).
+///
+/// [`smart_http::GitServiceTimeout`]: crate::git::smart_http::GitServiceTimeout
+#[derive(Debug, thiserror::Error)]
+#[error("no lock-pool connection available")]
+pub struct LockPoolBusy;
+
 /// Guard returned by `acquire_write()`. Holds the Postgres advisory lock and
 /// uploads to Tigris + releases the lock on `release()`.
 pub struct RepoWriteGuard {
@@ -354,8 +481,17 @@ pub struct RepoWriteGuard {
    repo_name: String,
    pub local_path: PathBuf,
    lock_key: i64,
-    pool: PgPool,
+    /// The lock-pool connection that TOOK the advisory lock. It must be the one
+    /// that releases it (session locks are owned by their connection), and
+    /// holding it here is also what makes a guard dropped without `release`
+    /// safe: the drop returns the connection through `after_release`, which
+    /// clears the lock.
+    lock_conn: PoolConnection<Postgres>,
    tigris: Option<TigrisClient>,
+    /// Shared with the store that handed this guard out; see
+    /// [`RepoStore::upload_site_reached`].
+    #[cfg(test)]
+    upload_site_reached: Arc<std::sync::atomic::AtomicUsize>,
 }

 impl RepoWriteGuard {
@@ -369,9 +505,16 @@ impl RepoWriteGuard {
    /// half-applied or otherwise inconsistent repo would propagate corruption to
    /// Tigris (and to every node that later downloads it). The lock is always
    /// released regardless, to avoid stale locks blocking future writes.
-    pub async fn release(self, success: bool) {
+    pub async fn release(mut self, success: bool) {
        // Upload to Tigris only on success.
        if success {
+            // The upload site, recorded for tests before the client is consulted: with
+            // no injectable seam on `TigrisClient` a counter inside the arm below could
+            // never move, and it is reaching this point at all that an interrupted push
+            // must not do (#173 F2).
+            #[cfg(test)]
+            self.upload_site_reached
+                .fetch_add(1, std::sync::atomic::Ordering::SeqCst);
            if let Some(ref tigris) = self.tigris {
                if let Err(e) = tigris
                    .upload(&self.owner_slug, &self.repo_name, &self.local_path)
@@ -384,14 +527,56 @@ impl RepoWriteGuard {
            warn!(repo = %self.repo_name, "write failed — skipping tigris upload to avoid propagating an inconsistent repo");
        }

-        // Release advisory lock
+        // Release the advisory lock on the connection that took it. Anything else
+        // (a fresh `&pool` checkout) is a no-op that returns false: Postgres
+        // scopes a session lock to its owning connection.
        let _ = sqlx::query("SELECT pg_advisory_unlock($1)")
            .bind(self.lock_key)
-            .execute(&self.pool)
+            .execute(&mut *self.lock_conn)
            .await;
+        // Dropping `self` returns the connection to the lock pool, where
+        // `after_release` sweeps anything the unlock above missed.
    }
 }

+/// Build the dedicated advisory-lock pool a `RepoStore` runs its write locks on.
+/// Connect options are cloned off an existing pool so callers need not re-parse
+/// the database URL; the pool is lazy, so no connection is opened here.
+///
+/// Two properties, both load-bearing:
+///
+///   * The `after_release` hook runs `pg_advisory_unlock_all()` before a
+///     connection goes back into the pool. sqlx's `PoolConnection::drop` spawns
+///     `return_to_pool()`, which invokes this hook, so a connection dropped by
+///     CANCELLATION still clears its locks. That is what keeps an `acquire_write`
+///     killed mid-Tigris by the caller's `tokio::time::timeout` from leaking a
+///     lock and wedging every later push to that repo (#173). Note the hook runs
+///     from that spawned task, so the unlock is asynchronous with respect to the
+///     drop: the lock clears shortly after the connection goes away, not
+///     synchronously with it.
+///   * It is a SEPARATE pool from the main query pool, not a slice of it. A push
+///     holds its lock connection for the whole receive-pack, and
+///     `db_max_connections` (default 20) is well below
+///     `max_concurrent_git_pushes` (default 32), so drawing these from the main
+///     pool would starve every other query during a push burst.
+///
+/// `acquire_timeout` bounds the wait when every lock-pool connection is busy, so
+/// exhaustion surfaces as a clean error rather than an unbounded hang.
+pub fn build_lock_pool(source: &PgPool, max_connections: u32, acquire_timeout: Duration) -> PgPool {
+    PgPoolOptions::new()
+        .max_connections(max_connections)
+        .acquire_timeout(acquire_timeout)
+        .after_release(|conn, _meta| {
+            Box::pin(async move {
+                sqlx::query("SELECT pg_advisory_unlock_all()")
+                    .execute(&mut *conn)
+                    .await?;
+                Ok(true)
+            })
+        })
+        .connect_lazy_with((*source.connect_options()).clone())
+}
+
 /// Compute a stable i64 hash for a Postgres advisory lock key.
 fn advisory_lock_key(owner_slug: &str, repo_name: &str) -> i64 {
    use std::hash::{Hash, Hasher};
@@ -404,6 +589,503 @@ fn advisory_lock_key(owner_slug: &str, repo_name: &str) -> i64 {
 #[cfg(test)]
 mod tests {
    use super::*;
+    use std::time::Duration;
+
+    // ── advisory-lock test helpers (#173 U1) ───────────────────────────────
+
+    /// Postgres advisory locks live in a CLUSTER-wide space, not a per-database
+    /// one, so two `#[sqlx::test]` cases running against their own temporary
+    /// databases still share the key space. Every lock test therefore mints its
+    /// own key instead of reusing a fixed constant.
+    fn unique_lock_key() -> i64 {
+        use std::sync::atomic::{AtomicI64, Ordering};
+        static NEXT: AtomicI64 = AtomicI64::new(0);
+        let n = NEXT.fetch_add(1, Ordering::Relaxed);
+        ((std::process::id() as i64) << 24) | (n & 0xff_ffff)
+    }
+
+    /// A plain pool (no `after_release` hook, no idle timeout) at the same
+    /// database as the `#[sqlx::test]` pool. Two separate reasons these tests
+    /// cannot just use the pool the harness hands them:
+    ///
+    /// 1. Observing lock state has to happen from a session that is definitely
+    ///    not the one under test. Session advisory locks are re-entrant, so
+    ///    `pg_try_advisory_lock` on the very connection that already holds the key
+    ///    returns true, and a same-pool probe silently reports a leaked lock free.
+    /// 2. The harness pool sets `idle_timeout(1s)`, so a connection returned to it
+    ///    is closed about a second later and Postgres drops every lock that
+    ///    session held. That would mask exactly the leak these tests exist to
+    ///    catch, so the store under test runs on one of these too.
+    fn sibling_pool(pool: &PgPool, max_connections: u32) -> PgPool {
+        sqlx::postgres::PgPoolOptions::new()
+            .max_connections(max_connections)
+            .connect_lazy_with((*pool.connect_options()).clone())
+    }
+
+    /// Probe the lock from a connection that is NOT the one under test. Session
+    /// advisory locks are re-entrant within their own session, so a check from the
+    /// holding connection would pass vacuously and prove nothing.
+    async fn lock_is_free_elsewhere(pool: &PgPool, key: i64) -> bool {
+        let mut probe = pool.acquire().await.expect("probe connection");
+        let taken: (bool,) = sqlx::query_as("SELECT pg_try_advisory_lock($1)")
+            .bind(key)
+            .fetch_one(&mut *probe)
+            .await
+            .expect("probe try-lock");
+        if taken.0 {
+            sqlx::query("SELECT pg_advisory_unlock($1)")
+                .bind(key)
+                .execute(&mut *probe)
+                .await
+                .expect("probe unlock");
+        }
+        taken.0
+    }
+
+    /// `after_release` runs from the task sqlx spawns in `PoolConnection::drop`,
+    /// so the unlock is ASYNCHRONOUS with respect to the drop. Callers must poll
+    /// rather than assume the lock is gone the instant the connection goes away.
+    async fn wait_until_free(pool: &PgPool, key: i64, within: Duration) -> bool {
+        let deadline = std::time::Instant::now() + within;
+        loop {
+            if lock_is_free_elsewhere(pool, key).await {
+                return true;
+            }
+            if std::time::Instant::now() >= deadline {
+                return false;
+            }
+            tokio::time::sleep(Duration::from_millis(25)).await;
+        }
+    }
+
+    // ── DESIGN GATE ────────────────────────────────────────────────────────
+    // The whole cancellation-safety design rests on one sqlx behaviour:
+    // `PoolConnection::drop` spawns `return_to_pool()`, which invokes the pool's
+    // `after_release` hook before the connection is reused. If that holds, a
+    // connection dropped by cancellation still runs `pg_advisory_unlock_all()`
+    // and the lock cannot leak. This test proves it by execution, through the
+    // production `build_lock_pool` so that stripping the hook there turns it red.
+
+    #[sqlx::test]
+    async fn dropped_pool_connection_runs_after_release_and_clears_locks(pool: PgPool) {
+        let key = unique_lock_key();
+        let lock_pool = build_lock_pool(&pool, 4, Duration::from_secs(5));
+
+        {
+            let mut conn = lock_pool.acquire().await.expect("lock-pool connection");
+            let taken: (bool,) = sqlx::query_as("SELECT pg_try_advisory_lock($1)")
+                .bind(key)
+                .fetch_one(&mut *conn)
+                .await
+                .expect("try-lock");
+            assert!(taken.0, "first try-lock must succeed");
+            assert!(
+                !lock_is_free_elsewhere(&pool, key).await,
+                "lock must be observably HELD from another session while the connection lives"
+            );
+            // Drop WITHOUT calling pg_advisory_unlock: this models cancellation.
+        }
+
+        assert!(
+            wait_until_free(&pool, key, Duration::from_secs(5)).await,
+            "after_release must clear the advisory lock of a dropped connection"
+        );
+    }
+
+    // ── acquire_write cancellation safety (#173 U1) ────────────────────────
+
+    /// The reviewer's named regression. `api/repos.rs` wraps `acquire_write` in a
+    /// `tokio::time::timeout`; when that fires during the Tigris phase the future
+    /// is dropped after the advisory lock was taken and before `RepoWriteGuard`
+    /// (the only thing that unlocks) exists. The lock then leaks and every later
+    /// push to the same repo spins the 60-attempt / 60s ceiling and fails.
+    #[sqlx::test]
+    async fn cancelled_acquire_write_mid_tigris_does_not_leak_the_lock(pool: PgPool) {
+        let repos_dir = PathBuf::from("/tmp/gitlawb-test-repos");
+        let owner = "did:key:z6MkCancelMidTigris";
+        let repo = "cancel-mid-tigris";
+
+        let store_pool = sibling_pool(&pool, 8);
+        let stalling = RepoStore::for_testing(repos_dir.clone(), store_pool.clone())
+            .with_tigris_stall(Duration::from_secs(30));
+        let cancelled = tokio::time::timeout(
+            Duration::from_millis(500),
+            stalling.acquire_write(owner, repo),
+        )
+        .await;
+        assert!(
+            cancelled.is_err(),
+            "the acquire must still be inside the Tigris phase when the timeout fires"
+        );
+
+        // Observed from an independent session, so the check cannot be satisfied
+        // by re-entrancy on whichever pooled connection happens to be handed back.
+        let probe = sibling_pool(&pool, 2);
+        let key = advisory_lock_key(&owner.replace([':', '/'], "_"), repo);
+        assert!(
+            wait_until_free(&probe, key, Duration::from_secs(5)).await,
+            "a cancelled acquire_write must leave no advisory lock held"
+        );
+
+        // A subsequent acquire for the SAME repo must succeed promptly. Before the
+        // fix it blocks on the leaked lock until the 60-attempt ceiling.
+        let store = RepoStore::for_testing(repos_dir, store_pool);
+        let guard = tokio::time::timeout(Duration::from_secs(5), store.acquire_write(owner, repo))
+            .await
+            .expect("second acquire_write must not block on a leaked lock")
+            .expect("second acquire_write must succeed");
+        guard.release(false).await;
+    }
+
+    /// Cancellation BEFORE the lock is taken must leave nothing behind: no lock,
+    /// and no lock-pool connection stranded. The lock pool here holds exactly one
+    /// connection, so a stranded one would make the follow-up acquire time out
+    /// waiting for a checkout.
+    #[sqlx::test]
+    async fn cancelled_acquire_write_before_the_lock_leaves_nothing_held(pool: PgPool) {
+        let probe = sibling_pool(&pool, 2);
+        let owner = "did:key:z6MkCancelEarly";
+        let repo = "cancel-early";
+        let key = advisory_lock_key(&owner.replace([':', '/'], "_"), repo);
+
+        let store = RepoStore::new(
+            PathBuf::from("/tmp/gitlawb-test-repos"),
+            None,
+            build_lock_pool(&pool, 1, Duration::from_secs(3)),
+        );
+
+        // A zero deadline polls the future once, which gets it no further than the
+        // first await (the pool checkout / the first try-lock round trip), so it is
+        // cancelled before any lock can be taken.
+        let cancelled =
+            tokio::time::timeout(Duration::ZERO, store.acquire_write(owner, repo)).await;
+        assert!(cancelled.is_err(), "the acquire must be cancelled");
+
+        assert!(
+            lock_is_free_elsewhere(&probe, key).await,
+            "no lock may be held when the acquire never got that far"
+        );
+
+        // The single lock-pool connection must be back: if cancellation stranded
+        // it, this checkout blocks until the 3s acquire timeout and fails.
+        let guard = tokio::time::timeout(Duration::from_secs(2), store.acquire_write(owner, repo))
+            .await
+            .expect("the lock-pool connection must have been returned")
+            .expect("acquire after cancellation");
+        guard.release(false).await;
+    }
+
+    /// Lock-pool exhaustion is a bounded wait and a clean error, never a panic and
+    /// never an unbounded hang.
+    #[sqlx::test]
+    async fn lock_pool_exhaustion_is_a_bounded_error(pool: PgPool) {
+        let owner = "did:key:z6MkExhaustion";
+        let store = RepoStore::new(
+            PathBuf::from("/tmp/gitlawb-test-repos"),
+            None,
+            build_lock_pool(&pool, 1, Duration::from_secs(2)),
+        );
+
+        let held = store
+            .acquire_write(owner, "exhaust-a")
+            .await
+            .expect("first acquire");
+
+        // Different repo, so this is not the advisory lock queueing: the only
+        // connection in the lock pool is checked out by `held`.
+        let started = std::time::Instant::now();
+        let err = tokio::time::timeout(
+            Duration::from_secs(10),
+            store.acquire_write(owner, "exhaust-b"),
+        )
+        .await
+        .expect("the wait must be bounded by the pool acquire timeout");
+        let err = match err {
+            Ok(_) => panic!("an exhausted lock pool must surface an error, not a guard"),
+            Err(e) => e,
+        };
+        assert!(
+            started.elapsed() < Duration::from_secs(6),
+            "the error must arrive on the acquire timeout, not after a long hang"
+        );
+        assert!(
+            err.to_string().contains("lock-pool connection"),
+            "the error must name the lock-pool checkout, got: {err}"
+        );
+
+        held.release(false).await;
+    }
+
+    /// #173 F1 (RED-before/GREEN-after). A contended `acquire_write` spins for up to
+    /// 60 one-second attempts. It must not OCCUPY a lock-pool connection for that whole
+    /// spin: `acquire_write` has non-push callers (`api/issues.rs`, `api/pulls.rs`) that
+    /// hold no concurrency permit, so any self-minted did:key could otherwise park a
+    /// connection per call and starve authenticated pushes on EVERY repo.
+    ///
+    /// Lock pool of exactly 2, two spinners. Pre-fix (checkout hoisted above the retry
+    /// loop) they pin both connections for the full spin and an UNCONTENDED acquire on a
+    /// third repo dies on the pool acquire timeout. Post-fix each spinner returns its
+    /// connection before sleeping, so it occupies ~0 and the uncontended acquire sails
+    /// through.
+    #[sqlx::test]
+    async fn a_spinning_acquire_write_does_not_occupy_a_lock_pool_connection(pool: PgPool) {
+        let owner = "did:key:z6MkSpinOccupancy";
+        let owner_slug = owner.replace([':', '/'], "_");
+        let store = RepoStore::new(
+            PathBuf::from("/tmp/gitlawb-test-repos"),
+            None,
+            build_lock_pool(&pool, 2, Duration::from_secs(2)),
+        );
+
+        // An independent session holds both contended keys, so the spinners' try-locks
+        // return false on every iteration and they stay in the retry loop.
+        let holder = sibling_pool(&pool, 2);
+        let mut held_conn = holder.acquire().await.expect("holder connection");
+        for repo in ["spin-a", "spin-b"] {
+            let taken: (bool,) = sqlx::query_as("SELECT pg_try_advisory_lock($1)")
+                .bind(advisory_lock_key(&owner_slug, repo))
+                .fetch_one(&mut *held_conn)
+                .await
+                .expect("holder try-lock");
+            assert!(taken.0, "the holder must own {repo}'s key");
+        }
+
+        let mut spinners = Vec::new();
+        for repo in ["spin-a", "spin-b"] {
+            let store = store.clone();
+            spinners.push(tokio::spawn(async move {
+                store.acquire_write(owner, repo).await
+            }));
+        }
+        // Let both reach the spin (each has done at least one failed try-lock by now).
+        tokio::time::sleep(Duration::from_millis(500)).await;
+
+        let started = std::time::Instant::now();
+        let uncontended = tokio::time::timeout(
+            Duration::from_secs(10),
+            store.acquire_write(owner, "spin-free"),
+        )
+        .await
+        .expect("the uncontended acquire must return, not hang");
+        let elapsed = started.elapsed();
+        let free_guard = uncontended.unwrap_or_else(|e| {
+            panic!(
+                "an UNCONTENDED acquire_write on a DIFFERENT repo must not be starved by \
+                 spinners holding the lock pool; got: {e}"
+            )
+        });
+        assert!(
+            elapsed < Duration::from_secs(2),
+            "the uncontended acquire must not queue behind the spinners for the pool \
+             acquire timeout; took {elapsed:?}"
+        );
+        free_guard.release(false).await;
+
+        // The drop-and-retake cycle must still END in a real, exclusive lock: free
+        // spin-a's key and the spinner that was cycling connections must take it.
+        sqlx::query("SELECT pg_advisory_unlock($1)")
+            .bind(advisory_lock_key(&owner_slug, "spin-a"))
+            .execute(&mut *held_conn)
+            .await
+            .expect("release spin-a");
+        let winner = tokio::time::timeout(Duration::from_secs(15), spinners.remove(0))
+            .await
+            .expect("the spinner must finish once its key frees")
+            .expect("spinner task")
+            .expect("the spinner must acquire once the key frees");
+        let probe = sibling_pool(&pool, 2);
+        assert!(
+            !lock_is_free_elsewhere(&probe, advisory_lock_key(&owner_slug, "spin-a")).await,
+            "the lock a spinner finally took must be observably held from another session"
+        );
+        winner.release(false).await;
+
+        for s in spinners {
+            s.abort();
+        }
+        sqlx::query("SELECT pg_advisory_unlock_all()")
+            .execute(&mut *held_conn)
+            .await
+            .expect("release the remaining holder lock");
+    }
+
+    /// #173 F1, the property the fix rests on: returning a lock-pool connection that
+    /// holds NOTHING runs `after_release`'s `pg_advisory_unlock_all()`, which is a no-op
+    /// and must not disturb a lock held on a DIFFERENT connection of the same pool.
+    /// Session advisory locks are per connection, so this is by construction, but the
+    /// spin fix depends on it, so it is proven by execution rather than assumed.
+    #[sqlx::test]
+    async fn returning_an_unlocked_connection_does_not_clear_another_connections_lock(
+        pool: PgPool,
+    ) {
+        let owner = "did:key:z6MkNoOpUnlockAll";
+        let repo = "noop-unlock";
+        let key = advisory_lock_key(&owner.replace([':', '/'], "_"), repo);
+        let probe = sibling_pool(&pool, 2);
+        let lock_pool = build_lock_pool(&pool, 4, Duration::from_secs(5));
+        let store = RepoStore::new(
+            PathBuf::from("/tmp/gitlawb-test-repos"),
+            None,
+            lock_pool.clone(),
+        );
+
+        let guard = store.acquire_write(owner, repo).await.expect("acquire");
+
+        // Churn the pool: check out and drop connections that hold no lock, exactly what
+        // a spinning acquire now does between attempts. Each return fires
+        // pg_advisory_unlock_all() on that connection.
+        for _ in 0..10 {
+            let mut conn = lock_pool.acquire().await.expect("churn checkout");
+            let _: (i32,) = sqlx::query_as("SELECT 1")
+                .fetch_one(&mut *conn)
+                .await
+                .expect("churn query");
+            drop(conn);
+            tokio::time::sleep(Duration::from_millis(10)).await;
+        }
+
+        assert!(
+            !lock_is_free_elsewhere(&probe, key).await,
+            "a held write lock must survive other lock-pool connections being returned"
+        );
+        guard.release(true).await;
+        assert!(
+            lock_is_free_elsewhere(&probe, key).await,
+            "release must still free the lock after the churn"
+        );
+    }
+
+    /// #173 F1: lock-pool exhaustion is a DISTINCT error the handler can shed as a 503,
+    /// not a generic git 500. Both directions: an exhausted pool downcasts to
+    /// [`LockPoolBusy`], and an unrelated failure (a rejected repo name) does not.
+    #[sqlx::test]
+    async fn lock_pool_exhaustion_is_a_distinct_downcastable_error(pool: PgPool) {
+        let owner = "did:key:z6MkBusyDowncast";
+        let store = RepoStore::new(
+            PathBuf::from("/tmp/gitlawb-test-repos"),
+            None,
+            build_lock_pool(&pool, 1, Duration::from_secs(1)),
+        );
+        let held = store
+            .acquire_write(owner, "busy-a")
+            .await
+            .expect("first acquire");
+
+        let err = match store.acquire_write(owner, "busy-b").await {
+            Ok(_) => panic!("an exhausted lock pool must error, not hand back a guard"),
+            Err(e) => e,
+        };
+        assert!(
+            err.downcast_ref::<LockPoolBusy>().is_some(),
+            "lock-pool exhaustion must be downcastable so the handler sheds 503, got: {err}"
+        );
+
+        // MUST-NOT: an ordinary rejection is not a capacity signal.
+        let other = match store.acquire_write(owner, "../escape").await {
+            Ok(_) => panic!("a traversal repo name must be rejected"),
+            Err(e) => e,
+        };
+        assert!(
+            other.downcast_ref::<LockPoolBusy>().is_none(),
+            "a validation failure must not masquerade as lock-pool capacity, got: {other}"
+        );
+
+        held.release(false).await;
+    }
+
+    /// Round trip: the lock is observably HELD between acquire and release, and
+    /// observably FREE after. Both checks run from an independent session; from
+    /// the holding session they would pass vacuously (session locks are
+    /// re-entrant) and would not notice an unlock that landed on the wrong
+    /// connection.
+    #[sqlx::test]
+    async fn acquire_write_holds_the_lock_until_release(pool: PgPool) {
+        let probe = sibling_pool(&pool, 2);
+        let owner = "did:key:z6MkRoundTrip";
+        let repo = "round-trip";
+        let key = advisory_lock_key(&owner.replace([':', '/'], "_"), repo);
+
+        let store = RepoStore::for_testing(PathBuf::from("/tmp/gitlawb-test-repos"), pool.clone());
+        let guard = store.acquire_write(owner, repo).await.expect("acquire");
+        assert!(
+            !lock_is_free_elsewhere(&probe, key).await,
+            "the lock must be held while the guard is alive"
+        );
+
+        // No polling here, deliberately. `release` must free the lock SYNCHRONOUSLY,
+        // which it can only do by unlocking on the connection that took it; a
+        // `pg_advisory_unlock` sent through the pool would land on some other
+        // session and return false. The `after_release` hook is a net for the
+        // cancellation path and fires from a spawned task well after this point, so
+        // it must not be what makes this assertion pass.
+        guard.release(true).await;
+        assert!(
+            lock_is_free_elsewhere(&probe, key).await,
+            "release must free the lock as seen from another session"
+        );
+    }
+
+    /// `release(false)` skips the Tigris upload but must still free the lock; a
+    /// failed write that kept the lock would wedge the repo.
+    #[sqlx::test]
+    async fn release_after_failed_write_still_frees_the_lock(pool: PgPool) {
+        let probe = sibling_pool(&pool, 2);
+        let owner = "did:key:z6MkFailedWrite";
+        let repo = "failed-write";
+        let key = advisory_lock_key(&owner.replace([':', '/'], "_"), repo);
+
+        let store = RepoStore::for_testing(PathBuf::from("/tmp/gitlawb-test-repos"), pool.clone());
+        let guard = store.acquire_write(owner, repo).await.expect("acquire");
+        guard.release(false).await;
+
+        assert!(
+            wait_until_free(&probe, key, Duration::from_secs(5)).await,
+            "release(success = false) must still free the lock"
+        );
+    }
+
+    /// The lock is per repo: a second acquire for the SAME repo waits for the
+    /// first to release, while a different repo proceeds straight through.
+    #[sqlx::test]
+    async fn same_repo_acquires_serialize_and_different_repos_do_not(pool: PgPool) {
+        let repos_dir = PathBuf::from("/tmp/gitlawb-test-repos");
+        let owner = "did:key:z6MkSerialize";
+        let store = RepoStore::for_testing(repos_dir, pool.clone());
+
+        let first = store
+            .acquire_write(owner, "serialize-a")
+            .await
+            .expect("first acquire");
+
+        // Different repo: unaffected by the held lock.
+        let other = tokio::time::timeout(
+            Duration::from_secs(2),
+            store.acquire_write(owner, "serialize-b"),
+        )
+        .await
+        .expect("a different repo must not wait on this lock")
+        .expect("acquire other repo");
+        other.release(false).await;
+
+        // Same repo: must not acquire while `first` is alive.
+        let contender = tokio::spawn({
+            let store = store.clone();
+            async move { store.acquire_write(owner, "serialize-a").await }
+        });
+        tokio::time::sleep(Duration::from_millis(1500)).await;
+        assert!(
+            !contender.is_finished(),
+            "a second acquire for the same repo must block while the first guard lives"
+        );
+
+        first.release(false).await;
+        let second = tokio::time::timeout(Duration::from_secs(10), contender)
+            .await
+            .expect("contender must finish once the lock is free")
+            .expect("contender task")
+            .expect("contender acquire");
+        second.release(false).await;
+    }

    // ── repo_name validation ───────────────────────────────────────────────

@@ -306,6 +306,90 @@ pub fn read_object_content(repo_path: &Path, sha256_hex: &str, obj_type: &str) -
    Ok(content_output.stdout)
 }

+/// Bounded twin of [`object_type`] for the `GET /ipfs/{cid}` serve path (#173
+/// round-10, R1/KTD2). Runs `git cat-file -t` under
+/// [`run_bounded_git`](crate::git::visibility_pack::run_bounded_git) so the child runs
+/// in its own process group and a watchdog reaps it (SIGTERM -> grace -> SIGKILL) at
+/// `timeout`. The bare [`object_type`] is a `spawn_blocking` `Command::output` that an
+/// async timeout cannot cancel, so a wedged `cat-file` there pins the caller's held
+/// /ipfs walk admission for the whole hang; this twin cannot. Semantics mirror
+/// [`object_type`]: `Ok(Some(t))` for an existing object, `Ok(None)` when git exits
+/// non-zero without timing out (the object is absent), and
+/// `Err(`[`GitServiceTimeout`](crate::git::smart_http::GitServiceTimeout)`)` on the
+/// deadline so the handler can mark the search truncated (retryable 503) rather than a
+/// false not-found. Callers off the /ipfs path keep the bare helper.
+pub fn object_type_bounded(
+    git_bin: &str,
+    repo_path: &Path,
+    sha256_hex: &str,
+    timeout: std::time::Duration,
+) -> Result<Option<String>> {
+    let deadline = std::time::Instant::now() + timeout;
+    match crate::git::visibility_pack::run_bounded_git(
+        git_bin,
+        &["cat-file", "-t", sha256_hex],
+        repo_path,
+        b"",
+        deadline,
+    ) {
+        Ok(out) => Ok(Some(String::from_utf8_lossy(&out).trim().to_string())),
+        Err(e) if e.is::<crate::git::smart_http::GitServiceTimeout>() => Err(e),
+        // A non-timeout failure is git reporting no such object (a non-zero exit),
+        // matching `object_type`'s `Ok(None)`.
+        Err(_) => Ok(None),
+    }
+}
+
+/// Bounded `git cat-file -s` size read for the `GET /ipfs/{cid}` serve path (#173
+/// round-10, R1/KTD2): reads the object size WITHOUT its content (so an oversized object
+/// is rejected before it is buffered, #173 F6), under
+/// [`run_bounded_git`](crate::git::visibility_pack::run_bounded_git) so a wedged size
+/// read is reaped at `timeout` instead of pinning the held /ipfs walk admission.
+/// `Ok(Some(n))` on success, `Ok(None)` when the object is absent (a non-timeout
+/// non-zero exit), `Err(GitServiceTimeout)` on the deadline.
+pub fn object_size_bounded(
+    git_bin: &str,
+    repo_path: &Path,
+    sha256_hex: &str,
+    timeout: std::time::Duration,
+) -> Result<Option<u64>> {
+    let deadline = std::time::Instant::now() + timeout;
+    match crate::git::visibility_pack::run_bounded_git(
+        git_bin,
+        &["cat-file", "-s", sha256_hex],
+        repo_path,
+        b"",
+        deadline,
+    ) {
+        Ok(out) => Ok(String::from_utf8_lossy(&out).trim().parse::<u64>().ok()),
+        Err(e) if e.is::<crate::git::smart_http::GitServiceTimeout>() => Err(e),
+        Err(_) => Ok(None),
+    }
+}
+
+/// Bounded twin of [`read_object_content`] for the `GET /ipfs/{cid}` serve path (#173
+/// round-10, R1/KTD2): `git cat-file <type>` under
+/// [`run_bounded_git`](crate::git::visibility_pack::run_bounded_git) so a wedged content
+/// read is reaped at `timeout` instead of pinning the held /ipfs walk admission. Returns
+/// the raw object bytes on success and an error (including `GitServiceTimeout` on the
+/// deadline) otherwise, mirroring [`read_object_content`].
+pub fn read_object_content_bounded(
+    git_bin: &str,
+    repo_path: &Path,
+    sha256_hex: &str,
+    obj_type: &str,
+    timeout: std::time::Duration,
+) -> Result<Vec<u8>> {
+    let deadline = std::time::Instant::now() + timeout;
+    crate::git::visibility_pack::run_bounded_git(
+        git_bin,
+        &["cat-file", obj_type, sha256_hex],
+        repo_path,
+        b"",
+        deadline,
+    )
+}
+
 /// Read a git object by its SHA-256 hex object ID.
 ///
 /// Returns `(object_type, content_bytes)` where `content_bytes` is the raw
@@ -323,6 +407,42 @@ pub fn read_object(repo_path: &Path, sha256_hex: &str) -> Result<Option<(String,
    Ok(Some((obj_type, content)))
 }

+/// Bounded twin of [`read_object`] for write-side callers that must not hang on a
+/// wedged `git cat-file` (the post-push pin path, #173): composes
+/// [`object_type_bounded`] and [`read_object_content_bounded`] under ONE shared
+/// deadline (mirroring `get_by_cid`'s read stage and `build_filtered_pack`), so a
+/// single object read holds for at most `timeout` total, not one full timeout per
+/// stage. `Ok(Some((type, bytes)))` on success, `Ok(None)` when the object is absent,
+/// and `Err(`[`GitServiceTimeout`](crate::git::smart_http::GitServiceTimeout)`)` when
+/// either stage overruns the deadline. The bare [`read_object`] is an unbounded
+/// `Command::output` an async timeout cannot cancel, so a wedged `cat-file` there pins
+/// the post-push coalescing key until process death; this twin cannot.
+pub fn read_object_bounded(
+    git_bin: &str,
+    repo_path: &Path,
+    sha256_hex: &str,
+    timeout: std::time::Duration,
+) -> Result<Option<(String, Vec<u8>)>> {
+    let deadline = std::time::Instant::now() + timeout;
+    let obj_type = match object_type_bounded(
+        git_bin,
+        repo_path,
+        sha256_hex,
+        deadline.saturating_duration_since(std::time::Instant::now()),
+    )? {
+        Some(t) => t,
+        None => return Ok(None),
+    };
+    let content = read_object_content_bounded(
+        git_bin,
+        repo_path,
+        sha256_hex,
+        &obj_type,
+        deadline.saturating_duration_since(std::time::Instant::now()),
+    )?;
+    Ok(Some((obj_type, content)))
+}
+
 /// Get the diff between two branches: changes on source_branch not in target_branch.
 pub fn branch_diff(repo_path: &Path, target_branch: &str, source_branch: &str) -> Result<String> {
    let output = Command::new("git")
@@ -501,4 +621,84 @@ mod tests {
            "unchanged file must not appear: {names:?}"
        );
    }
+
+    /// #173 round-10 (KTD2): `object_type_bounded` reaps a wedged `cat-file` child at its
+    /// deadline instead of blocking on it to natural exit, so a hung probe cannot pin the
+    /// /ipfs walk admission the owning task holds. A fake `git` records its pid and sleeps
+    /// far past the 1s deadline; the `run_bounded_git` watchdog (SIGTERM -> grace ->
+    /// SIGKILL of the process group) must kill it well before that natural exit, and the
+    /// call must surface `GitServiceTimeout`. REVERT PROOF (RED): swap the twin's
+    /// `run_bounded_git` for the bare `Command::output()` and the wedged child stays alive
+    /// past the deadline — the mid-flight liveness poll below reads it still running.
+    #[cfg(unix)]
+    #[test]
+    fn object_type_bounded_reaps_wedged_child_at_deadline() {
+        use std::time::Duration;
+        let tmp = tempfile::TempDir::new().unwrap();
+        let pidfile = tmp.path().join("catfile.pid");
+        // `cat-file` records its own pid then sleeps 8s (>> the 1s deadline) so the probe
+        // is genuinely wedged; the watchdog is what must end it.
+        let body = format!(
+            "#!/bin/sh\n\
+             case \"$1\" in\n\
+               cat-file) echo $$ > \"{}\"; sleep 8 ;;\n\
+               *) : ;;\n\
+             esac\n\
+             exit 0\n",
+            pidfile.display()
+        );
+        let git_path = tmp.path().join("fakegit");
+        std::fs::write(&git_path, &body).unwrap();
+        {
+            use std::os::unix::fs::PermissionsExt;
+            let mut perm = std::fs::metadata(&git_path).unwrap().permissions();
+            perm.set_mode(0o755);
+            std::fs::set_permissions(&git_path, perm).unwrap();
+        }
+        let repo = tmp.path().to_path_buf();
+        let git = git_path.to_str().unwrap().to_string();
+
+        let alive = |pid: i32| unsafe { libc::kill(pid, 0) == 0 };
+
+        // The bounded probe blocks until the watchdog tears the child down, so run it on
+        // a worker thread and poll for the reap from here.
+        let handle = std::thread::spawn(move || {
+            super::object_type_bounded(&git, &repo, "deadbeef", Duration::from_secs(1))
+        });
+
+        let mut pid = None;
+        for _ in 0..500 {
+            if let Some(p) = std::fs::read_to_string(&pidfile)
+                .ok()
+                .and_then(|s| s.trim().parse::<i32>().ok())
+            {
+                pid = Some(p);
+                break;
+            }
+            std::thread::sleep(Duration::from_millis(10));
+        }
+        let pid = pid.expect("the fake cat-file must have spawned and recorded its pid");
+
+        // Past the 1s deadline + SIGTERM grace but well before the 8s natural exit: the
+        // watchdog must already have reaped the wedged group. A bare, unbounded read would
+        // leave it running here — the load-bearing RED.
+        std::thread::sleep(Duration::from_secs(3));
+        let reaped = !alive(pid);
+        // Defensive reap so a RED run leaks no orphan.
+        unsafe {
+            libc::kill(pid, libc::SIGKILL);
+        }
+        assert!(
+            reaped,
+            "object_type_bounded must reap the wedged cat-file child at the deadline, \
+             not leave it running to its natural exit"
+        );
+
+        let res = handle.join().expect("probe thread joins");
+        let err = res.expect_err("a deadline overrun must be an error, not a value");
+        assert!(
+            err.is::<crate::git::smart_http::GitServiceTimeout>(),
+            "a deadline overrun must surface GitServiceTimeout, got: {err:?}"
+        );
+    }
 }
@@ -9,6 +9,372 @@

 use anyhow::Result;
 use gitlawb_core::cid::Cid;
+use std::time::Duration;
+
+/// Attempts (including the first) for a transient DB-record retry.
+const PIN_RECORD_ATTEMPTS: u32 = 3;
+/// Backoff between DB-record retry attempts.
+const PIN_RECORD_BACKOFF: Duration = Duration::from_millis(50);
+
+/// Run an idempotent DB-record operation with a bounded retry so a sub-second
+/// transient error does not silently leave the pin-source set permanently
+/// incomplete. The resolver treats a nonempty below-cap source set as complete,
+/// so a dropped `record_pin_source`/`record_pinned_cid` makes `GET /ipfs/{cid}`
+/// 404 a valid public copy. Every wrapped insert is idempotent (`ON CONFLICT DO
+/// NOTHING` / provenance-preserving upsert), so re-running is safe. On exhausted
+/// attempts the last error is returned and the caller records the durable
+/// `pin_sources_incomplete` marker (U3, #173), which is what keeps the resolver's
+/// bounded scan fallback available for that object instead of 404ing a public copy.
+/// Shared with the `pinata.rs` twin so both pin paths retry identically. Runs
+/// inside the already-detached post-push task, so the backoff adds no push latency.
+pub(crate) async fn retry_db_record<F, Fut>(mut op: F) -> Result<()>
+where
+    F: FnMut() -> Fut,
+    Fut: std::future::Future<Output = Result<()>>,
+{
+    let mut attempt = 1;
+    loop {
+        match op().await {
+            Ok(()) => return Ok(()),
+            Err(e) => {
+                if attempt >= PIN_RECORD_ATTEMPTS {
+                    return Err(e);
+                }
+                tokio::time::sleep(PIN_RECORD_BACKOFF).await;
+                attempt += 1;
+            }
+        }
+    }
+}
+
+/// Opportunistically repair a legacy provider-CID row on the already-pinned skip
+/// path (#173 R8, KTD8). Releases before this branch stored the PROVIDER CID
+/// (Kubo dag-pb / Pinata CIDv0) in `pinned_cids.cid`; the `/ipfs` resolver
+/// recomputes the raw CID from object bytes and 404s any row whose key does not
+/// match, yet `list_pinned_cids` still advertises the stored key — so a client
+/// gets a CID the resolver deliberately withholds. When a re-push carries the
+/// object again, rewrite the key to the raw CID and stash the old provider value
+/// in `legacy_provider_cid`.
+///
+/// COST GATE: candidacy is decided from the stored key's codec alone — a
+/// CIDv1/raw key is already the resolver key and reads NO bytes, keeping the
+/// steady-state skip cost DB-only. Only a legacy-codec row reads the object to
+/// recompute. A row whose bytes are gone stays withheld (no destructive rewrite).
+async fn repair_legacy_provider_cid(
+    repo_path: &std::path::Path,
+    git_bin: &str,
+    git_timeout: Duration,
+    sha: &str,
+    db: &crate::db::Db,
+) -> Result<RepairOutcome> {
+    let stored = match db.cid_for_oid(sha).await? {
+        Some(c) => c,
+        None => return Ok(RepairOutcome::Settled),
+    };
+    // Cost gate: a canonical raw CIDv1 key is already correct — never read bytes.
+    if gitlawb_core::cid::is_raw_cidv1(&stored) {
+        return Ok(RepairOutcome::Settled);
+    }
+    // Legacy-codec row: read the object to recompute. Counted so a test can prove
+    // the gate above spares non-legacy rows this read.
+    #[cfg(test)]
+    note_legacy_repair_read();
+    // `read_object_bounded` is SYNCHRONOUS `git cat-file`, and its budget is
+    // `git_service_timeout_secs` (600 by default), so running it inline parks a tokio
+    // worker for as long as git takes: one wedged read on the sweep's first pass at boot
+    // holds a worker for ten minutes, per legacy row. Push it to the blocking pool, the
+    // same shape `replication_withheld_set` uses in api/repos.rs (#173 round 11, F4).
+    // Both callers of this function are async, so neither changes shape. The read-counter
+    // increment above stays on THIS thread so the thread_local cost-gate assertion holds.
+    let read = {
+        let repo_path = repo_path.to_path_buf();
+        let git_bin = git_bin.to_string();
+        let sha = sha.to_string();
+        tokio::task::spawn_blocking(move || {
+            crate::git::store::read_object_bounded(&git_bin, &repo_path, &sha, git_timeout)
+        })
+        .await
+    };
+    let data = match read {
+        Ok(Ok(Some((_ty, bytes)))) => bytes,
+        // Bytes gone: the row stays withheld, never destructively rewritten. Nothing a
+        // later pass changes, so this is a TERMINAL outcome for the sweep's re-walk gate.
+        Ok(Ok(None)) => return Ok(RepairOutcome::Settled),
+        // A wedged/D-state `git cat-file` (timeout/infra): the repair is opportunistic
+        // and best-effort, so skip it and return Ok so the pin task PROCEEDS to
+        // requeue_or_release rather than hanging the coalescing key until process death
+        // (grok F2, #173). A later re-push or the deferred sweep retries the repair.
+        Ok(Err(e)) => {
+            tracing::warn!(sha = %sha, err = %e, "skipping legacy provider-CID repair: bounded object read failed");
+            return Ok(RepairOutcome::Retryable);
+        }
+        // The blocking task panicked or was cancelled: same best-effort treatment, and
+        // worth another walk because it says nothing about the row itself.
+        Err(e) => {
+            tracing::warn!(sha = %sha, err = %e, "skipping legacy provider-CID repair: object read task failed");
+            return Ok(RepairOutcome::Retryable);
+        }
+    };
+    let raw = Cid::from_git_object_bytes(&data).to_string();
+    if raw == stored {
+        return Ok(RepairOutcome::Settled);
+    }
+    db.repair_legacy_provider_cid(sha, &raw, &stored).await?;
+    Ok(RepairOutcome::Repaired)
+}
+
+/// What one opportunistic repair did with a row, so the sweep can tell a skip a later
+/// run could fix from one nothing will (U4 re-walk, #173 round 11). The push skip path
+/// ignores the value: it repairs whatever the push happens to carry and a failure there
+/// is already warn-only.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub(crate) enum RepairOutcome {
+    /// Nothing to do, or nothing a re-walk would change: the stored key is already the
+    /// raw resolver key, the recomputed key matches it, or the object's bytes are gone.
+    Settled,
+    /// The bounded object read failed (a wedged `git cat-file`, an unreadable repo).
+    /// The bytes may be readable later, so the row is worth walking again.
+    Retryable,
+    /// The row's key was rewritten to the raw-content CID.
+    Repaired,
+}
+
+/// What one sweep pass (or a whole sweep run) did. `scanned` counts `pinned_cids`
+/// rows READ, which is the quantity the batch size bounds; `repaired` counts rows
+/// whose key was actually rewritten to the raw CID.
+#[derive(Debug, Default, PartialEq, Eq)]
+pub(crate) struct SweepStats {
+    pub scanned: usize,
+    pub repaired: usize,
+    pub passes: usize,
+    /// Rows left unrepaired for a reason a LATER run could fix (the source repo is not
+    /// on this node's local disk, a DB read failed, a bounded object read failed). A
+    /// nonzero count is what makes the run rewind its cursor instead of parking it at
+    /// the end of the table forever. Rows that are unrepairable in principle (no
+    /// provenance, the repo row is gone, the bytes are gone) are NOT counted here.
+    pub retryable_skips: usize,
+}
+
+/// One bounded pass of the U4 sweep: read at most `batch` `pinned_cids` rows after
+/// the persisted cursor, repair the legacy ones, and persist the new cursor.
+///
+/// The batch is what bounds the pass. It caps rows READ, not rows repaired, because
+/// the legacy predicate is a codec decode SQL cannot express; a table of raw rows
+/// therefore costs one indexed range scan per pass and nothing else.
+///
+/// The cursor advances to the LAST row read whatever happened to each row, including
+/// rows that were skipped as unrepairable. A cursor that only advanced on success
+/// would re-read the same unrepairable row on every pass and the sweep would never
+/// reach the rows behind it.
+async fn sweep_pass(
+    repos_dir: &std::path::Path,
+    git_bin: &str,
+    git_timeout: Duration,
+    batch: i64,
+    db: &crate::db::Db,
+) -> Result<SweepStats> {
+    let cursor = db.pin_repair_cursor().await?;
+    let rows = db.pinned_cids_after(&cursor, batch).await?;
+    let scanned = rows.len();
+    let mut repaired = 0usize;
+    let mut retryable_skips = 0usize;
+    let mut last = cursor;
+
+    for (sha, stored) in rows {
+        // Advance FIRST: every path below this line may skip the row, and none of them
+        // may wedge the walk (scenario 7).
+        last = sha.clone();
+        // Same cost gate as the skip-path repair: a canonical raw CIDv1 key is already
+        // the resolver key, so it reads no bytes and resolves no repo.
+        if gitlawb_core::cid::is_raw_cidv1(&stored) {
+            continue;
+        }
+        // Resolve the row's repo from its recorded provenance (first-pinner plus the
+        // bounded additional source set). An empty set is a pin recorded before
+        // provenance existed: nothing to read the bytes from, so skip it.
+        let sources = match db.pin_sources_for_oid(&sha).await {
+            Ok(s) => s,
+            Err(e) => {
+                tracing::warn!(sha = %sha, err = %e, "sweep: failed to read pin sources");
+                // A DB read error says nothing about the row, so a later run retries it.
+                retryable_skips += 1;
+                continue;
+            }
+        };
+        // Whether this row ended the source walk repaired, and whether anything it hit
+        // along the way was a transient obstacle rather than a permanent one.
+        let mut row_repaired = false;
+        let mut row_retryable = false;
+        for repo_id in sources {
+            let repo = match db.get_repo_by_id(&repo_id).await {
+                Ok(Some(r)) => r,
+                // The repo row is gone: a later source may still hold the bytes. A
+                // deleted repo does not come back, so this is not a retryable skip.
+                Ok(None) => continue,
+                Err(e) => {
+                    tracing::warn!(repo_id = %repo_id, err = %e, "sweep: failed to read repo");
+                    row_retryable = true;
+                    continue;
+                }
+            };
+            // Derive the LOCAL disk path rather than going through `repo_store.acquire`.
+            // The sweep is opportunistic background maintenance over every pinned row on
+            // the node, so it must never pull a cold repo back from remote storage: that
+            // would turn a repair pass into a bulk restore. A repo that is not on local
+            // disk simply reads no bytes here and stays withheld, but it IS a retryable
+            // skip: on a Tigris-backed node the repo is cold now and warm later, and
+            // without the re-walk that row would never be repaired by anything.
+            // The path goes through the repo store's VALIDATED resolver (allowlisted
+            // components, rooted at repos_dir, no ParentDir/CurDir segment), not the raw
+            // join: the sweep is a second caller of that path logic and gets the same
+            // barrier the acquire path has (#173 round 11, F3). It is the non-fetching
+            // variant, so the no-cold-pull property above is untouched.
+            let repo_path = match crate::git::repo_store::validated_repo_disk_path(
+                repos_dir,
+                &repo.owner_did,
+                &repo.name,
+            ) {
+                Ok(p) => p,
+                // An unsafe name is not something a later run fixes, so it is terminal.
+                Err(e) => {
+                    tracing::warn!(repo_id = %repo_id, err = %e, "sweep: rejected unsafe repo path");
+                    continue;
+                }
+            };
+            if !repo_path.is_dir() {
+                row_retryable = true;
+                continue;
+            }
+            match repair_legacy_provider_cid(&repo_path, git_bin, git_timeout, &sha, db).await {
+                Ok(RepairOutcome::Repaired) => {
+                    repaired += 1;
+                    row_repaired = true;
+                    break;
+                }
+                // The bytes could not be read from this source right now: try the next
+                // source, and if none of them works, walk the row again on a later run.
+                Ok(RepairOutcome::Retryable) => row_retryable = true,
+                // Nothing to repair from this source and nothing a re-walk changes.
+                Ok(RepairOutcome::Settled) => {}
+                Err(e) => {
+                    tracing::warn!(sha = %sha, err = %e, "sweep: legacy provider-CID repair failed");
+                    row_retryable = true;
+                }
+            }
+        }
+        if !row_repaired && row_retryable {
+            retryable_skips += 1;
+        }
+    }
+
+    db.set_pin_repair_cursor(&last).await?;
+    Ok(SweepStats {
+        scanned,
+        repaired,
+        passes: 1,
+        retryable_skips,
+    })
+}
+
+/// Test seam for a single bounded pass (scenarios 4 and 5 drive passes by hand to
+/// observe the batch bound and the restart-resumes-from-cursor behavior).
+#[cfg_attr(not(test), allow(dead_code))]
+pub(crate) async fn sweep_legacy_provider_cids_once(
+    repos_dir: &std::path::Path,
+    git_bin: &str,
+    git_timeout: Duration,
+    batch: i64,
+    db: &crate::db::Db,
+) -> Result<SweepStats> {
+    sweep_pass(repos_dir, git_bin, git_timeout, batch, db).await
+}
+
+/// U4 (#173): the one-shot legacy provider-CID migration sweep.
+///
+/// Releases before this branch stored the PROVIDER CID (Kubo dag-pb / Pinata CIDv0)
+/// in `pinned_cids.cid`. This branch's `/ipfs/{cid}` resolver recomputes the raw
+/// content CID and withholds any row whose key does not match, so those rows are
+/// unresolvable. The opportunistic repair on the already-pinned skip path only fires
+/// when a later push re-carries the object, and normal git negotiation omits objects
+/// the node already has, so on an upgraded node that push generally never comes. This
+/// walks the table instead.
+///
+/// Runs until a pass comes back short of a full batch, which is the end of the table.
+/// Sleeps `delay` between full batches so it cannot monopolize the DB, and persists
+/// its cursor every pass so a restart continues instead of rewinding. Errors reading
+/// or repairing an individual row are warn-and-skip; only a failure of the batch query
+/// or the cursor write ends the run, and a later run picks up from the stored cursor.
+///
+/// A run that skipped at least one RETRYABLE row rewinds the cursor to the start of the
+/// table on its way out (#173 round 11). Without that the cursor parked at the maximum
+/// `sha256_hex` for good: every later boot read zero rows, so a row skipped for a
+/// transient reason (its repo cold on a Tigris-backed node, a DB or object read error)
+/// was skipped permanently, unadvertised and unresolvable with nothing left to fix it.
+/// The rewind is a per-RUN decision made after the walk has already finished, never
+/// mid-walk, so it cannot spin: the cost is one extra ordered scan on the next run, and
+/// a row that is unrepairable in principle (bytes gone, provenance gone) does not count
+/// as retryable, so a node holding one does not re-walk on every boot forever.
+pub(crate) async fn sweep_legacy_provider_cids(
+    repos_dir: &std::path::Path,
+    git_bin: &str,
+    git_timeout: Duration,
+    batch: i64,
+    delay: Duration,
+    db: &crate::db::Db,
+) -> SweepStats {
+    let mut totals = SweepStats::default();
+    loop {
+        let pass = match sweep_pass(repos_dir, git_bin, git_timeout, batch, db).await {
+            Ok(p) => p,
+            Err(e) => {
+                tracing::warn!(err = %e, "legacy provider-CID sweep pass failed; stopping");
+                break;
+            }
+        };
+        totals.scanned += pass.scanned;
+        totals.repaired += pass.repaired;
+        totals.retryable_skips += pass.retryable_skips;
+        totals.passes += 1;
+        // A short batch means the ordered walk reached the end of the table. Stop here
+        // rather than after an extra empty pass, and do NOT sleep on the way out.
+        if (pass.scanned as i64) < batch {
+            break;
+        }
+        tokio::time::sleep(delay).await;
+    }
+    if totals.retryable_skips > 0 {
+        if let Err(e) = db.set_pin_repair_cursor("").await {
+            tracing::warn!(err = %e, "failed to rewind the legacy provider-CID sweep cursor");
+        }
+    }
+    totals
+}
+
+// Test-only cost-gate counter (R8, U7): how many times the opportunistic repair
+// read an object's bytes on the skip path. The codec gate must spare a CIDv1/raw
+// row this read; the counter is the both-ways guard (removing the gate reads the
+// raw row and increments it). Same thread_local discipline as the serve-path
+// oversize counter — the pin tests await `pin_new_objects` on a current-thread
+// runtime, so the increment and the assertion share one thread.
+#[cfg(test)]
+thread_local! {
+    static LEGACY_REPAIR_READS: std::cell::Cell<usize> = const { std::cell::Cell::new(0) };
+}
+
+#[cfg(test)]
+pub(crate) fn reset_legacy_repair_reads() {
+    LEGACY_REPAIR_READS.with(|c| c.set(0));
+}
+
+#[cfg(test)]
+pub(crate) fn legacy_repair_reads() -> usize {
+    LEGACY_REPAIR_READS.with(|c| c.get())
+}
+
+#[cfg(test)]
+fn note_legacy_repair_read() {
+    LEGACY_REPAIR_READS.with(|c| c.set(c.get() + 1));
+}

 /// Pin a single git object to the local IPFS/Kubo node.
 ///
@@ -91,14 +457,18 @@ pub async fn cat(ipfs_api: &str, cid: &str) -> Result<Vec<u8>> {
 /// `..._fail_closed` filter on the full-scan path before calling, so this
 /// function never sees a withheld blob. `repo_path` is still needed to read each
 /// object's bytes. The twin in `pinata.rs` mirrors this shape — change both in
-/// lockstep.
+/// lockstep. `repo_id` records the pin's provenance so `GET /ipfs/{cid}` resolves
+/// straight to this repo instead of scanning every repo (#173).
 ///
 /// Returns a list of `(sha256_hex, cid)` pairs for objects pinned this call.
 pub async fn pin_new_objects(
    ipfs_api: &str,
    repo_path: &std::path::Path,
+    git_bin: &str,
+    git_timeout: Duration,
    object_list: Vec<String>,
    db: &crate::db::Db,
+    repo_id: &str,
 ) -> Vec<(String, String)> {
    if ipfs_api.is_empty() {
        return vec![];
@@ -107,9 +477,54 @@ pub async fn pin_new_objects(
    let mut pinned = Vec::new();

    for sha in object_list {
-        // Skip if already pinned
+        // Skip if already pinned — but first backfill provenance if the existing
+        // pin has none. A legacy pin (recorded before repo_id existed, #173, jatmn)
+        // is skipped here before record_pinned_cid ever runs, so its NULL provenance
+        // would never resolve to one repo and known CIDs keep hitting the scan. The
+        // backfill only sets repo_id (AND repo_id IS NULL guard preserves
+        // first-pinner-owns) and never re-pins the bytes — the object is already on IPFS.
        match db.is_pinned(&sha).await {
-            Ok(true) => continue,
+            Ok(true) => {
+                match db.provenance_for_oid(&sha).await {
+                    Ok(None) => {
+                        if let Err(e) = db.backfill_pin_provenance(&sha, repo_id).await {
+                            tracing::warn!(sha = %sha, err = %e, "failed to backfill pin provenance");
+                        }
+                    }
+                    Ok(Some(_)) => {}
+                    Err(e) => {
+                        tracing::warn!(sha = %sha, err = %e, "DB error reading pin provenance");
+                    }
+                }
+                // F1 (#173 round 8): record this repo as an ADDITIONAL source for the
+                // already-pinned object. This is the load-bearing skip-branch insert —
+                // a later repo pushing a shared object hits this path (already pinned),
+                // and without it `GET /ipfs/{cid}` only ever knows the first pinner, so a
+                // shared object first pinned from a private/quarantined repo 404s even
+                // when this repo would serve it. Bounded per object (MAX_PIN_SOURCES).
+                if let Err(e) = retry_db_record(|| db.record_pin_source(&sha, repo_id)).await {
+                    tracing::warn!(sha = %sha, err = %e, "failed to record pin source");
+                    // U3 (#173): the retries are spent and this repo is NOT in the source
+                    // set, so the set is known incomplete. Persist that, or the resolver
+                    // reads a non-empty below-cap set as COMPLETE and 404s an object this
+                    // repo would serve. Warn-only in turn: if the marker write also fails
+                    // the object degrades to the pre-U3 behavior, never worse.
+                    if let Err(e) = db.mark_pin_sources_incomplete(&sha).await {
+                        tracing::warn!(sha = %sha, err = %e, "failed to mark pin sources incomplete");
+                    }
+                }
+                // R8 (#173 round 10): opportunistically repair a legacy provider-CID
+                // row (Kubo dag-pb / Pinata) to the raw-content resolver key on this
+                // re-push. Cost-gated on the stored key's codec — a non-legacy row
+                // reads no bytes. Warn-only: a failure leaves the row as-is for a
+                // later re-push or the deferred one-shot sweep.
+                if let Err(e) =
+                    repair_legacy_provider_cid(repo_path, git_bin, git_timeout, &sha, db).await
+                {
+                    tracing::warn!(sha = %sha, err = %e, "failed to repair legacy provider CID");
+                }
+                continue;
+            }
            Ok(false) => {}
            Err(e) => {
                tracing::warn!(sha = %sha, err = %e, "DB error checking pinned status");
@@ -117,22 +532,49 @@ pub async fn pin_new_objects(
            }
        }

-        // Read raw object content
-        let data = match crate::git::store::read_object(repo_path, &sha) {
-            Ok(Some((_obj_type, bytes))) => bytes,
-            Ok(None) => continue,
-            Err(e) => {
-                tracing::warn!(sha = %sha, err = %e, "failed to read git object for pinning");
-                continue;
-            }
-        };
+        // Read raw object content under a bounded read so a wedged/D-state `git
+        // cat-file` (stuck NFS/Tigris backend) is reaped at `git_timeout` instead of
+        // hanging pin_new_objects forever — which would pin the post-push coalescing
+        // key until process death (grok F2, #173). On Err the object is simply not
+        // pinned this pass; a later pass/push retries.
+        let data =
+            match crate::git::store::read_object_bounded(git_bin, repo_path, &sha, git_timeout) {
+                Ok(Some((_obj_type, bytes))) => bytes,
+                Ok(None) => continue,
+                Err(e) => {
+                    tracing::warn!(sha = %sha, err = %e, "failed to read git object for pinning");
+                    continue;
+                }
+            };

        // Pin to IPFS
        match pin_git_object(ipfs_api, &sha, &data).await {
            Ok(cid) if !cid.is_empty() => {
-                if let Err(e) = db.record_pinned_cid(&sha, &cid).await {
+                // The resolver key (`pinned_cids.cid`) must be the locally-computed
+                // raw-content CID, never the provider Hash: Kubo returns a dag-pb/UnixFS
+                // root for objects above its block size, which does not hash the raw
+                // content, so `GET /ipfs/{provider_cid}` would resolve then fail the F2
+                // integrity check (list-then-404). The serve path reads bytes from git and
+                // verifies them against the requested CID, so the raw CID is the correct
+                // key. Mirrors the pinata twin, which already records the raw CID.
+                let raw_cid = gitlawb_core::cid::Cid::from_git_object_bytes(&data).to_string();
+                // F1 (#173 round 8): the first pinner is recorded in pin_repo_sources too,
+                // so every source (first and subsequent) is tried uniformly by the
+                // resolver. U3 (#173): the pin and its source go down in ONE transaction.
+                // As two independent best-effort calls this path could land the pin while
+                // dropping its own source, producing a source set silently missing its
+                // first pinner; atomically there is no such window, and a total failure
+                // leaves the object unpinned so the next push retries the whole thing.
+                if let Err(e) =
+                    retry_db_record(|| db.record_pinned_cid_with_source(&sha, &raw_cid, repo_id))
+                        .await
+                {
                    tracing::warn!(sha = %sha, err = %e, "failed to record pinned CID in DB");
                }
+                // Return the provider Hash (not the resolver key), mirroring the pinata
+                // twin's contract: the DB `cid` is the raw resolver key (recorded above),
+                // the returned value is the provider CID. Here the return is consumed only
+                // for logging, but keeping the twins structurally identical avoids drift.
                pinned.push((sha, cid));
            }
            Ok(_) => {}
@@ -144,3 +586,92 @@ pub async fn pin_new_objects(

    pinned
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::cell::Cell;
+
+    // The retry helper is the load-bearing unit: it converts a sub-second
+    // transient DB error at the three warn-only record sites into a landed row,
+    // instead of a permanently incomplete pin-source set. These drive the helper
+    // directly against a controlled closure (the record sites take a concrete
+    // `&Db` over a `PgPool`, so a failing-first wrapper cannot slot in without
+    // changing signatures — see U6 seam note).
+
+    #[tokio::test]
+    async fn retry_lands_after_transient_failures() {
+        let calls = Cell::new(0u32);
+        let result = retry_db_record(|| {
+            let n = calls.get() + 1;
+            calls.set(n);
+            async move {
+                if n < PIN_RECORD_ATTEMPTS {
+                    Err(anyhow::anyhow!("transient failure on attempt {n}"))
+                } else {
+                    Ok(())
+                }
+            }
+        })
+        .await;
+
+        assert!(
+            result.is_ok(),
+            "retry lands the row after transient failures"
+        );
+        assert_eq!(
+            calls.get(),
+            PIN_RECORD_ATTEMPTS,
+            "op is retried until it succeeds"
+        );
+    }
+
+    #[tokio::test]
+    async fn retry_returns_last_err_after_exhaustion() {
+        let calls = Cell::new(0u32);
+        let result = retry_db_record(|| {
+            let n = calls.get() + 1;
+            calls.set(n);
+            async move { Err::<(), _>(anyhow::anyhow!("attempt {n} failed")) }
+        })
+        .await;
+
+        let err = result.expect_err("all attempts fail so the last error surfaces");
+        assert_eq!(
+            calls.get(),
+            PIN_RECORD_ATTEMPTS,
+            "attempts are bounded to the cap"
+        );
+        assert_eq!(
+            err.to_string(),
+            "attempt 3 failed",
+            "the LAST error is returned, not the first"
+        );
+    }
+
+    // Happy path against a real DB: a single-attempt success lands the row, and a
+    // redundant call is idempotent (`ON CONFLICT DO NOTHING`), so the source set
+    // holds exactly one row.
+    #[sqlx::test]
+    async fn retry_records_pin_source_once(pool: sqlx::PgPool) {
+        let db = crate::db::Db::for_testing(pool);
+        db.run_migrations().await.unwrap();
+
+        let sha = "a".repeat(64);
+        let repo_id = "repo-retry-1";
+
+        retry_db_record(|| db.record_pin_source(&sha, repo_id))
+            .await
+            .expect("happy-path record succeeds in one attempt");
+        retry_db_record(|| db.record_pin_source(&sha, repo_id))
+            .await
+            .expect("a redundant record is idempotent");
+
+        let sources = db.pin_sources_for_oid(&sha).await.unwrap();
+        assert_eq!(
+            sources,
+            vec![repo_id.to_string()],
+            "exactly one source row lands under ON CONFLICT DO NOTHING"
+        );
+    }
+}
@@ -24,8 +24,14 @@ mod test_support;
 mod visibility;
 mod webhooks;

-use anyhow::{Context, Result};
+use anyhow::{anyhow, Context, Result};
+use axum::extract::State;
+use axum::http::StatusCode;
+use axum::response::IntoResponse;
+use axum::routing::get;
+use axum::{Json, Router};
 use clap::Parser;
+use std::sync::atomic::{AtomicU64, Ordering};
 use std::sync::Arc;
 use tokio::net::TcpListener;
 use tokio::sync::watch;
@@ -38,6 +44,46 @@ use config::Config;
 use db::Db;
 use state::AppState;

+#[derive(Clone)]
+struct DegradedState {
+    node_did: String,
+    db_startup: Arc<DbStartupStatus>,
+}
+
+/// Two independent counters with no cross-field invariant — atomics, not a
+/// lock, so the retry loop and the degraded handlers never contend.
+#[derive(Default)]
+struct DbStartupStatus {
+    attempts: AtomicU64,
+    next_retry_secs: AtomicU64,
+}
+
+/// Hard ceiling on the advisory-lock pool's `max_connections`.
+///
+/// `max_concurrent_git_pushes` is validated all the way up to 1_048_576, and the lock
+/// pool used to derive its size straight from that knob, so raising the push cap
+/// silently raised the node's Postgres connection ceiling with no CLI error and no
+/// relation to the server's own `max_connections` (#173 F4). The node's total budget is
+/// now bounded: `db_max_connections` (default 20) + at most this.
+const LOCK_POOL_MAX_CONNECTIONS: u32 = 64;
+
+/// Connections the lock pool keeps above the push cap. Covers the three non-push
+/// `acquire_write` callers (`api/issues.rs` x2, `api/pulls.rs`), which hold no
+/// concurrency permit, so a push never queues here for a connection where it did not
+/// before.
+const LOCK_POOL_PUSH_HEADROOM: u8 = 8;
+
+/// Size the advisory-lock pool for a given push cap: the cap plus
+/// [`LOCK_POOL_PUSH_HEADROOM`], clamped to [`LOCK_POOL_MAX_CONNECTIONS`]. Past the
+/// clamp a push may wait for a lock-pool connection, which is a bounded wait that sheds
+/// a clean 503 (see `LockPoolBusy`), not an unbounded hang.
+fn lock_pool_size(max_concurrent_git_pushes: usize) -> u32 {
+    u32::try_from(max_concurrent_git_pushes)
+        .unwrap_or(u32::MAX)
+        .saturating_add(u32::from(LOCK_POOL_PUSH_HEADROOM))
+        .min(LOCK_POOL_MAX_CONNECTIONS)
+}
+
 #[tokio::main]
 async fn main() -> Result<()> {
    tracing_subscriber::fmt()
@@ -76,21 +122,101 @@ async fn main() -> Result<()> {
        env!("CARGO_PKG_VERSION")
    );
    info!("╚══════════════════════════════════════════╝");
-    info!(did = %node_did, "node identity");
-    info!(addr = %config.bind_addr(), "listening");
-
    // Process-wide shutdown signal. One sender lives in AppState (cloned
    // into every handler); main() keeps a clone and flips it on SIGINT
    // or SIGTERM. Tasks that hold a watch::Receiver get notified at
    // their next await point.
    let (shutdown_tx, _shutdown_rx_for_main) = watch::channel(false);
+    spawn_shutdown_signal(shutdown_tx.clone());

-    // Connect to PostgreSQL database
-    let db = Arc::new(
-        Db::connect(&config.database_url)
-            .await
-            .context("failed to connect to database")?,
-    );
+    info!(did = %node_did, "node identity");
+    info!(addr = %config.bind_addr(), "binding HTTP listener");
+
+    // Bind HTTP once, before dependency initialization, and keep this socket
+    // for the life of the process. The degraded server accepts on a dup of the
+    // same socket, so the degraded→full handoff never closes the port: while
+    // the full server initializes, connections queue in the shared backlog
+    // instead of being refused.
+    let listener = TcpListener::bind(config.bind_addr())
+        .await
+        .with_context(|| format!("failed to bind to {}", config.bind_addr()))?;
+    let full_std_listener = listener.into_std()?;
+    let degraded_listener = TcpListener::from_std(
+        full_std_listener
+            .try_clone()
+            .context("failed to clone HTTP listener for degraded server")?,
+    )?;
+
+    // Metrics must stay observable during a database outage — the degraded
+    // window is exactly when dashboards need data — so this listener starts
+    // before the DB connects.
+    let metrics_handle = if !config.metrics_addr.is_empty() {
+        match spawn_metrics_server(&config.metrics_addr, shutdown_tx.subscribe()).await {
+            Ok(handle) => {
+                info!(addr = %config.metrics_addr, "metrics endpoint listening");
+                Some(handle)
+            }
+            Err(e) => {
+                warn!(err = %e, addr = %config.metrics_addr, "failed to start metrics endpoint — continuing without");
+                None
+            }
+        }
+    } else {
+        info!("metrics endpoint disabled (GITLAWB_METRICS_ADDR not set)");
+        None
+    };
+
+    let db_startup = Arc::new(DbStartupStatus::default());
+    let (db_ready_tx, db_ready_rx) = watch::channel(false);
+    let mut degraded_handle = tokio::spawn(run_degraded_server(
+        degraded_listener,
+        node_did.to_string(),
+        Arc::clone(&db_startup),
+        db_ready_rx,
+        shutdown_tx.subscribe(),
+    ));
+
+    // Connect to PostgreSQL database. A transient outage or bad secret should
+    // not crash-loop the process and hammer the database provider; permanent
+    // misconfiguration surfaces through error-level logs and the /ready check.
+    let db = tokio::select! {
+        db = connect_db_with_retry(&config, Arc::clone(&db_startup), shutdown_tx.subscribe()) => {
+            match db {
+                Some(db) => db,
+                None => {
+                    // Shutdown requested while waiting for the database. The
+                    // degraded server only serves one-shot 503s — abort it
+                    // rather than drain, so a slow client can't stall exit.
+                    degraded_handle.abort();
+                    return Ok(());
+                }
+            }
+        }
+        degraded = &mut degraded_handle => {
+            if *shutdown_tx.borrow() {
+                return Ok(());
+            }
+            return match degraded {
+                Ok(Ok(())) => Err(anyhow!("degraded HTTP server stopped before database became ready")),
+                Ok(Err(err)) => Err(err.context("degraded HTTP server failed")),
+                Err(err) => Err(anyhow!("degraded HTTP server task failed: {err}")),
+            };
+        }
+    };
+
+    // Flip the degraded server into graceful shutdown, but do NOT await the
+    // drain: one slow in-flight request must not delay the full server, and
+    // the shared socket means there is no port gap to cover. The drain
+    // finishes (and logs) in the background.
+    db_ready_tx.send(true).ok();
+    tokio::spawn(async move {
+        match degraded_handle.await {
+            Ok(Ok(())) => {}
+            Ok(Err(err)) => warn!(err = %err, "degraded HTTP server exited with error"),
+            Err(err) => warn!(err = %err, "degraded HTTP server task failed"),
+        }
+    });
+    info!(addr = %config.bind_addr(), "database ready; starting full HTTP server");

    // Prune peer rows that point back at this node (stale self-loop entries)
    if let Some(public_url) = config.public_url.as_deref() {
@@ -179,14 +305,43 @@ async fn main() -> Result<()> {
        None
    };

-    let repo_store =
-        git::repo_store::RepoStore::new(config.repos_dir.clone(), tigris, db.pool().clone());
+    // Repo write locks run on their own pool, never the main query pool: each
+    // push holds its connection for the whole receive-pack, and
+    // db_max_connections (20) is below max_concurrent_git_pushes (32), so sharing
+    // would starve every other query under a push burst. See build_lock_pool for
+    // the cancellation semantics (#173).
+    let lock_pool = git::repo_store::build_lock_pool(
+        db.pool(),
+        lock_pool_size(config.max_concurrent_git_pushes),
+        std::time::Duration::from_secs(config.db_acquire_timeout_secs),
+    );
+    let repo_store = git::repo_store::RepoStore::new(config.repos_dir.clone(), tigris, lock_pool);

    // Per-DID limiter for the creation endpoints. Keyed on the authenticated
    // DID (attacker-varied), so bound its key set to cap memory.
    let rate_limiter =
        rate_limit::RateLimiter::new_bounded(10, std::time::Duration::from_secs(3600), 200_000);

+    // Per-client-IP flood brake for the creation endpoints. The per-DID limiter
+    // above is bypassed by a DID farm (one throwaway did:key per repo), which is
+    // exactly how the recurring spam-repo floods get past both it and the
+    // iCaptcha gate. Keyed on the resolved client IP so a single-source flood is
+    // capped regardless of how many identities it mints. Sized well above any
+    // legitimate per-IP creation rate; GITLAWB_CREATE_RATE_LIMIT overrides, 0
+    // disables. Bounded key set — the key is a client-influenced IP.
+    let create_limit = std::env::var("GITLAWB_CREATE_RATE_LIMIT")
+        .ok()
+        .and_then(|v| v.trim().parse::<usize>().ok())
+        .unwrap_or(120);
+    let create_ip_rate_limiter = rate_limit::RateLimiter::new_bounded(
+        create_limit,
+        std::time::Duration::from_secs(3600),
+        200_000,
+    );
+    if create_limit == 0 {
+        tracing::warn!("GITLAWB_CREATE_RATE_LIMIT=0 — per-IP creation rate limiting disabled");
+    }
+
    // Push-path flood brake: max git-receive-pack requests per client IP per
    // hour (counts both the info/refs advertisement and the push POST). Sized
    // for heavy agent automation while still stopping flood traffic (the June
@@ -213,6 +368,29 @@ async fn main() -> Result<()> {
    );
    tracing::info!(trust = ?push_limiter_trust, push_limit, "push rate limiter configured");

+    // Peer-sync flood brakes, keyed on the resolved client IP (per-DID is useless
+    // here — a did:key farm self-registers). Two buckets so an unsigned notify
+    // flood can't drain the signed trigger caller's quota (#82). Bounded key sets
+    // (the key is a client-influenced IP); 0 disables each.
+    let sync_trigger_rate_limiter = rate_limit::RateLimiter::new_bounded(
+        config.sync_trigger_rate_limit,
+        std::time::Duration::from_secs(3600),
+        200_000,
+    );
+    let peer_write_rate_limiter = rate_limit::RateLimiter::new_bounded(
+        config.peer_write_rate_limit,
+        std::time::Duration::from_secs(3600),
+        200_000,
+    );
+    if config.sync_trigger_rate_limit == 0 {
+        tracing::warn!(
+            "GITLAWB_SYNC_TRIGGER_RATE_LIMIT=0 — /sync/trigger IP rate limiting disabled"
+        );
+    }
+    if config.peer_write_rate_limit == 0 {
+        tracing::warn!("GITLAWB_PEER_WRITE_RATE_LIMIT=0 — peer-write IP rate limiting disabled");
+    }
+
    // Initialize the iCaptcha proof gate (inert unless ICAPTCHA_MODE is set).
    icaptcha::init().await;

@@ -229,10 +407,85 @@ async fn main() -> Result<()> {
        machine_id,
        repo_store,
        rate_limiter,
+        create_ip_rate_limiter,
        push_rate_limiter,
+        ipfs_max_history_walks: crate::api::ipfs::MAX_HISTORY_WALKS_PER_REQUEST,
+        // The legacy-probe budget is operator-tunable via GITLAWB_IPFS_MAX_REPOS_WALKED
+        // (R5); the history-walk ceiling above stays constant (a smaller value false-503s
+        // a provenanced request). Default 256 preserves the shipped behaviour.
+        ipfs_max_legacy_probes: AppState::ipfs_legacy_probe_budget(&config),
+        ipfs_max_served_object_bytes: crate::api::ipfs::MAX_SERVED_OBJECT_BYTES,
        push_limiter_trust,
+        sync_trigger_rate_limiter,
+        peer_write_rate_limiter,
        shutdown_tx: shutdown_tx.clone(),
+        git_read_semaphore: Arc::new(tokio::sync::Semaphore::new(config.max_concurrent_git_ops)),
+        git_write_semaphore: Arc::new(tokio::sync::Semaphore::new(
+            config.max_concurrent_git_pushes,
+        )),
+        // Anon receive-pack advertisements get their OWN pool, same size as the
+        // write pool but disjoint, so filling it (which takes many source IPs, each
+        // capped by git_push_advert_per_caller) never occupies a permit the
+        // authenticated POST needs (#174).
+        git_push_advert_semaphore: Arc::new(tokio::sync::Semaphore::new(
+            config.max_concurrent_git_pushes,
+        )),
+        // Bounds concurrent detached post-push encryption walks, sized from the push
+        // pool (no separate knob — Q1): completed pushes cannot outnumber active
+        // encryption walks past this (#174 P1-e).
+        git_encrypt_semaphore: Arc::new(tokio::sync::Semaphore::new(
+            config.max_concurrent_git_pushes,
+        )),
+        // Coalesces the DETACHED post-push encryption tasks per repo so a rapid pusher
+        // cannot grow the outstanding parked-waiter set past one task per repo (#174
+        // P2-2). No knob: it is a natural cap (one entry per distinct repo), not a
+        // sized pool.
+        encrypt_inflight: crate::state::EncryptInflight::new(),
+        git_read_per_caller: rate_limit::PerCallerConcurrency::with_default_max_keys(
+            config.max_concurrent_reads_per_caller,
+        ),
+        // Per-source cap on the receive-pack advertisement, sized to an eighth of the
+        // write pool (min 1): a single source can hold at most this many write-pool
+        // slots via the anon advertisement, so saturating the pool takes ~8 distinct
+        // source IPs, each also rate-limited (#174).
+        git_push_advert_per_caller: rate_limit::PerCallerConcurrency::with_default_max_keys(
+            (config.max_concurrent_git_pushes / 8).max(1),
+        ),
+        // Per-source cap on the authenticated receive-pack POST, sized like the advert
+        // cap: one source IP can hold at most this many write-pool slots, so
+        // monopolizing the pool takes ~8 distinct source IPs, each also rate-limited
+        // (#174 P1-d).
+        git_write_per_caller: rate_limit::PerCallerConcurrency::with_default_max_keys(
+            (config.max_concurrent_git_pushes / 8).max(1),
+        ),
+        // Bounds concurrent /ipfs visibility walks — a distinct public cost center, so
+        // its own pool + per-source sub-cap + per-IP rate limiter, never a git pool
+        // (#174 P1-3). The per-source map is bounded (reject-before-insert, INV-15).
+        git_ipfs_walk_semaphore: Arc::new(tokio::sync::Semaphore::new(
+            config.max_concurrent_ipfs_walks,
+        )),
+        git_ipfs_walk_per_caller: rate_limit::PerCallerConcurrency::with_default_max_keys(
+            config.ipfs_walk_per_source,
+        ),
+        ipfs_rate_limiter: rate_limit::RateLimiter::new_bounded(
+            config.ipfs_rate_limit,
+            std::time::Duration::from_secs(3600),
+            200_000,
+        ),
+        // Separate WORK-budget bucket for the resolver's per-probe/per-walk charges (R6).
+        // Its capacity is DERIVED from the route limit (no new knob) and floored at the
+        // legacy-probe budget, so one full default-config legacy scan never self-throttles
+        // mid-request while the route brake above stays the pure once-per-request cap.
+        ipfs_work_rate_limiter: rate_limit::RateLimiter::new_bounded(
+            AppState::ipfs_work_budget(&config),
+            std::time::Duration::from_secs(3600),
+            200_000,
+        ),
+        git_bin: "git".to_string(),
    };
+    if config.ipfs_rate_limit == 0 {
+        tracing::warn!("GITLAWB_IPFS_RATE_LIMIT=0 — per-IP /ipfs rate limiting disabled");
+    }

    // Periodic peer-count poll for the metrics gauge. If p2p is disabled
    // we still set the gauge to 0 so dashboards don't show "no data".
@@ -260,46 +513,18 @@ async fn main() -> Result<()> {
        });
    }

-    // Spawn a task that flips the shutdown signal on SIGINT or SIGTERM.
-    // On Unix, both signals are handled. On Windows, only Ctrl-C is
-    // supported by tokio::signal::ctrl_c.
-    {
-        let tx = shutdown_tx.clone();
-        tokio::spawn(async move {
-            #[cfg(unix)]
-            {
-                use tokio::signal::unix::{signal as unix_signal, SignalKind};
-                let mut sigterm =
-                    unix_signal(SignalKind::terminate()).expect("install SIGTERM handler");
-                let mut sigint =
-                    unix_signal(SignalKind::interrupt()).expect("install SIGINT handler");
-                tokio::select! {
-                    _ = sigterm.recv() => info!("SIGTERM received, shutting down"),
-                    _ = sigint.recv()  => info!("SIGINT received, shutting down"),
-                }
-            }
-            #[cfg(not(unix))]
-            {
-                use tokio::signal;
-                let _ = signal::ctrl_c().await;
-                info!("Ctrl-C received, shutting down");
-            }
-            tx.send(true).ok();
-        });
-    }
-
    // Periodic cleanup of expired rate limit entries + consumed-proof ledger
    {
-        let rl = state.rate_limiter.clone();
-        let push_rl = state.push_rate_limiter.clone();
+        let cleanup_state = state.clone();
        let db = state.db.clone();
        let mut shutdown_rx = state.subscribe_shutdown();
        tokio::spawn(async move {
            loop {
                tokio::select! {
                    _ = tokio::time::sleep(std::time::Duration::from_secs(300)) => {
-                        rl.cleanup().await;
-                        push_rl.cleanup().await;
+                        // Sweep every per-IP/DID limiter (incl. the ipfs walk brake)
+                        // so bounded maps shed stale keys instead of sitting at cap.
+                        cleanup_state.sweep_rate_limiters().await;
                        let now = std::time::SystemTime::now()
                            .duration_since(std::time::UNIX_EPOCH)
                            .map(|d| d.as_secs() as i64)
@@ -318,10 +543,13 @@ async fn main() -> Result<()> {
        });
    }

+    let _legacy_cid_sweep = spawn_legacy_cid_sweep(&state, &config);
+
    let router = server::build_router(state.clone());
-    let listener = TcpListener::bind(config.bind_addr())
-        .await
-        .with_context(|| format!("failed to bind to {}", config.bind_addr()))?;
+    // Re-register the socket bound at startup — same fd, so there was never a
+    // moment with the port closed between the degraded and full servers.
+    let listener = TcpListener::from_std(full_std_listener)
+        .context("failed to re-register HTTP listener with the runtime")?;

    info!("✓ node started — did:{}", node_did);
    info!("  repos dir: {}", config.repos_dir.display());
@@ -330,23 +558,6 @@ async fn main() -> Result<()> {
        &config.database_url.split('@').next_back().unwrap_or("?")
    );

-    // Optional Prometheus metrics listener on a separate port.
-    let metrics_handle = if !config.metrics_addr.is_empty() {
-        match spawn_metrics_server(&config.metrics_addr, state.clone()).await {
-            Ok(handle) => {
-                info!(addr = %config.metrics_addr, "metrics endpoint listening");
-                Some(handle)
-            }
-            Err(e) => {
-                warn!(err = %e, addr = %config.metrics_addr, "failed to start metrics endpoint — continuing without");
-                None
-            }
-        }
-    } else {
-        info!("metrics endpoint disabled (GITLAWB_METRICS_ADDR not set)");
-        None
-    };
-
    // Publish our DID record to the Kademlia DHT shortly after startup
    if let Some(p2p) = &state.p2p {
        let did_record = p2p::DidRecord {
@@ -456,12 +667,267 @@ async fn main() -> Result<()> {
    Ok(())
 }

+/// U4 (#173): spawn the one-shot legacy provider-CID repair sweep. Releases before this
+/// version stored the PROVIDER CID (Kubo dag-pb / Pinata CIDv0) in `pinned_cids.cid`,
+/// and this version's `/ipfs/{cid}` resolver withholds any row whose stored key is not
+/// the raw-content CID. The opportunistic repair on the pin path only fires when a push
+/// re-carries the object, which normal git negotiation makes it not do, so those rows
+/// need a walk. DETACHED, never on the boot path: the caller keeps serving while this
+/// runs, and the sweep's own batch bound plus inter-batch delay keep it off the DB's
+/// critical path. Its cursor is durable, so a restart mid-walk resumes instead of
+/// rewinding.
+///
+/// A named function rather than an inline block in `main` so the WIRING has a seam a
+/// test can call: that the task is spawned at all, that it reads its batch and delay
+/// from the config knobs rather than some other field, that the caller is not blocked
+/// on it, and that the shutdown watcher actually ends it mid-walk. The sweep's own
+/// behavior is covered elsewhere; this is the boot-path half.
+fn spawn_legacy_cid_sweep(state: &AppState, config: &Config) -> tokio::task::JoinHandle<()> {
+    let db = state.db.clone();
+    let repos_dir = config.repos_dir.clone();
+    let git_bin = state.git_bin.clone();
+    let git_timeout = std::time::Duration::from_secs(config.git_service_timeout_secs);
+    let batch = config.pin_repair_sweep_batch;
+    let delay = std::time::Duration::from_secs(config.pin_repair_sweep_delay_secs);
+    let mut shutdown_rx = state.subscribe_shutdown();
+    tokio::spawn(async move {
+        tokio::select! {
+            stats = ipfs_pin::sweep_legacy_provider_cids(
+                &repos_dir, &git_bin, git_timeout, batch, delay, &db,
+            ) => {
+                if stats.repaired > 0 {
+                    tracing::info!(
+                        scanned = stats.scanned,
+                        repaired = stats.repaired,
+                        "legacy provider-CID sweep finished"
+                    );
+                }
+            }
+            // Shutdown mid-walk simply drops the run; the persisted cursor means the
+            // next boot picks up where this one stopped.
+            _ = shutdown_rx.changed() => {}
+        }
+    })
+}
+
+fn spawn_shutdown_signal(tx: watch::Sender<bool>) {
+    tokio::spawn(async move {
+        #[cfg(unix)]
+        {
+            use tokio::signal::unix::{signal as unix_signal, SignalKind};
+            let mut sigterm =
+                unix_signal(SignalKind::terminate()).expect("install SIGTERM handler");
+            let mut sigint = unix_signal(SignalKind::interrupt()).expect("install SIGINT handler");
+            tokio::select! {
+                _ = sigterm.recv() => info!("SIGTERM received, shutting down"),
+                _ = sigint.recv()  => info!("SIGINT received, shutting down"),
+            }
+        }
+        #[cfg(not(unix))]
+        {
+            use tokio::signal;
+            let _ = signal::ctrl_c().await;
+            info!("Ctrl-C received, shutting down");
+        }
+        tx.send(true).ok();
+    });
+}
+
+async fn connect_db_with_retry(
+    config: &Config,
+    db_startup: Arc<DbStartupStatus>,
+    mut shutdown_rx: watch::Receiver<bool>,
+) -> Option<Arc<Db>> {
+    let initial_retry_secs = config.db_retry_initial_secs;
+    let max_retry_secs = config.db_retry_max_secs.max(initial_retry_secs);
+    let acquire_timeout = std::time::Duration::from_secs(config.db_acquire_timeout_secs);
+    let attempt_timeout = std::time::Duration::from_secs(config.db_connect_timeout_secs);
+    let mut attempts = 0_u64;
+
+    loop {
+        if *shutdown_rx.borrow() {
+            return None;
+        }
+
+        attempts = attempts.saturating_add(1);
+        db_startup.attempts.store(attempts, Ordering::Relaxed);
+
+        // Bound the whole attempt, not just the pool connect: migrations
+        // block on a cross-instance advisory lock, and an unbounded wait
+        // there would wedge this loop — no retries, no logs, no recovery.
+        // Timing out and retrying is safe; migrations are idempotent.
+        let attempt = match tokio::time::timeout(
+            attempt_timeout,
+            Db::connect(
+                &config.database_url,
+                config.db_max_connections,
+                acquire_timeout,
+            ),
+        )
+        .await
+        {
+            Ok(result) => result,
+            Err(_) => Err(anyhow!(
+                "connect + migrate attempt exceeded {}s (GITLAWB_DB_CONNECT_TIMEOUT_SECS); \
+                 is another instance holding the migration lock?",
+                attempt_timeout.as_secs()
+            )),
+        };
+
+        match attempt {
+            Ok(db) => {
+                info!(attempts, "database connection established");
+                return Some(Arc::new(db));
+            }
+            Err(err) => {
+                // A bad DATABASE_URL or rejected credentials won't heal on
+                // their own. Still retry (exiting would crash-loop and hammer
+                // the provider — and take liveness down with it), but log at
+                // error level and skip straight to the maximum backoff; the
+                // /ready health check is what surfaces this to deploys.
+                let permanent = is_likely_permanent_db_error(&err);
+                let retry_secs = if permanent {
+                    max_retry_secs
+                } else {
+                    database_retry_delay_secs(initial_retry_secs, max_retry_secs, attempts)
+                };
+                db_startup
+                    .next_retry_secs
+                    .store(retry_secs, Ordering::Relaxed);
+                if permanent {
+                    tracing::error!(
+                        attempts,
+                        retry_secs,
+                        err = %err,
+                        "database rejected our configuration (bad DATABASE_URL or credentials?) — retrying, but operator action is likely required"
+                    );
+                } else {
+                    warn!(
+                        attempts,
+                        retry_secs,
+                        err = %err,
+                        "database unavailable during startup; retrying"
+                    );
+                }
+
+                tokio::select! {
+                    _ = tokio::time::sleep(std::time::Duration::from_secs(retry_secs)) => {}
+                    changed = shutdown_rx.changed() => {
+                        if changed.is_err() || *shutdown_rx.borrow() {
+                            return None;
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+
+/// Errors that indicate misconfiguration rather than a transient outage: a
+/// malformed DATABASE_URL, or a server that answered and rejected us —
+/// Postgres error class 28xxx (invalid authorization) or 3D000 (database
+/// does not exist). Best-effort: an error that anyhow can't downcast back to
+/// sqlx just counts as transient.
+fn is_likely_permanent_db_error(err: &anyhow::Error) -> bool {
+    match err.downcast_ref::<sqlx::Error>() {
+        Some(sqlx::Error::Configuration(_)) => true,
+        Some(sqlx::Error::Database(db)) => db
+            .code()
+            .map(|c| c.starts_with("28") || c.starts_with("3D"))
+            .unwrap_or(false),
+        _ => false,
+    }
+}
+
+fn database_retry_delay_secs(initial_secs: u64, max_secs: u64, attempts: u64) -> u64 {
+    // The exponent bound only keeps the u32 cast safe — max_secs is the real
+    // (operator-configurable) cap, and saturating math handles overflow.
+    let exponent = attempts.saturating_sub(1).min(63) as u32;
+    initial_secs
+        .saturating_mul(2_u64.saturating_pow(exponent))
+        .min(max_secs)
+}
+
+async fn run_degraded_server(
+    listener: TcpListener,
+    node_did: String,
+    db_startup: Arc<DbStartupStatus>,
+    mut db_ready_rx: watch::Receiver<bool>,
+    mut shutdown_rx: watch::Receiver<bool>,
+) -> Result<()> {
+    let addr = listener.local_addr().ok();
+    let router = build_degraded_router(node_did, db_startup);
+    info!(?addr, "degraded HTTP server ready");
+
+    axum::serve(listener, router)
+        .with_graceful_shutdown(async move {
+            // wait_for resolves on predicate-true or sender-drop; either way
+            // this phase is over.
+            tokio::select! {
+                _ = db_ready_rx.wait_for(|ready| *ready) => {}
+                _ = shutdown_rx.wait_for(|stop| *stop) => {}
+            }
+        })
+        .await?;
+
+    Ok(())
+}
+
+fn build_degraded_router(node_did: String, db_startup: Arc<DbStartupStatus>) -> Router {
+    let state = DegradedState {
+        node_did,
+        db_startup,
+    };
+    // Everything answers 503 with the same body — including /health and
+    // /ready, so peer pings (which treat any 2xx /health as alive) and
+    // uptime monitors correctly see a node that cannot serve traffic.
+    // `/` additionally carries the node identity for probing peers.
+    Router::new()
+        .route("/", get(degraded_node_info))
+        .fallback(degraded_unavailable)
+        .with_state(state)
+}
+
+/// One source of truth for the degraded 503 body, sharing the error
+/// vocabulary with error.rs so clients see the same code/message for
+/// "database unavailable" regardless of which phase produced it.
+fn degraded_body(db_startup: &DbStartupStatus) -> serde_json::Value {
+    serde_json::json!({
+        "status": "degraded",
+        "database": "initializing",
+        "error": error::DB_UNAVAILABLE_CODE,
+        "message": error::DB_UNAVAILABLE_MESSAGE,
+        "db_attempts": db_startup.attempts.load(Ordering::Relaxed),
+        "db_next_retry_secs": db_startup.next_retry_secs.load(Ordering::Relaxed),
+    })
+}
+
+async fn degraded_node_info(State(state): State<DegradedState>) -> impl IntoResponse {
+    let mut body = degraded_body(&state.db_startup);
+    if let Some(obj) = body.as_object_mut() {
+        obj.insert("name".into(), "gitlawb-node".into());
+        obj.insert("version".into(), env!("CARGO_PKG_VERSION").into());
+        obj.insert("did".into(), state.node_did.clone().into());
+    }
+    (StatusCode::SERVICE_UNAVAILABLE, Json(body))
+}
+
+async fn degraded_unavailable(State(state): State<DegradedState>) -> impl IntoResponse {
+    (
+        StatusCode::SERVICE_UNAVAILABLE,
+        Json(degraded_body(&state.db_startup)),
+    )
+}
+
 /// Spawn a small axum router that exposes only `GET /metrics` on its own
 /// listener. Returns the JoinHandle so `main()` can abort it on shutdown.
 /// This is deliberately separate from the main router so the metrics port
 /// can be firewalled differently from the API port — bind to localhost
 /// or a private interface only.
-async fn spawn_metrics_server(addr: &str, state: AppState) -> Result<tokio::task::JoinHandle<()>> {
+async fn spawn_metrics_server(
+    addr: &str,
+    mut shutdown_rx: watch::Receiver<bool>,
+) -> Result<tokio::task::JoinHandle<()>> {
    use axum::{response::IntoResponse, routing::get, Router};

    async fn metrics_handler() -> impl IntoResponse {
@@ -485,7 +951,6 @@ async fn spawn_metrics_server(addr: &str, state: AppState) -> Result<tokio::task
        }
    }

-    let mut shutdown_rx = state.subscribe_shutdown();
    let listener = TcpListener::bind(addr)
        .await
        .with_context(|| format!("failed to bind metrics listener to {addr}"))?;
@@ -705,6 +1170,140 @@ fn load_or_create_keypair(config: &Config) -> Result<Keypair> {
    }
 }

+#[cfg(test)]
+mod legacy_cid_sweep_wiring_tests {
+    use super::spawn_legacy_cid_sweep;
+    use sqlx::PgPool;
+    use std::time::Duration;
+
+    /// Seed `count` `pinned_cids` rows whose keys are already canonical raw CIDv1, in a
+    /// known `sha256_hex` order. The sweep's own cost gate skips a raw-CIDv1 row without
+    /// reading bytes or resolving a repo, so each row is SCANNED (it advances the cursor)
+    /// and nothing else. That is what makes the cursor a clean readout of how far the
+    /// walk got, with no dependency on repos on disk.
+    async fn seed_scannable_rows(pool: &PgPool, count: usize) -> Vec<String> {
+        let mut shas = Vec::new();
+        for i in 1..=count {
+            let sha = format!("wire{i:02}");
+            let cid = gitlawb_core::cid::Cid::from_git_object_bytes(sha.as_bytes()).to_string();
+            assert!(
+                gitlawb_core::cid::is_raw_cidv1(&cid),
+                "the seeded key must hit the sweep's raw-CIDv1 skip, not a repair attempt"
+            );
+            sqlx::query("INSERT INTO pinned_cids (sha256_hex, cid, pinned_at) VALUES ($1, $2, $3)")
+                .bind(&sha)
+                .bind(&cid)
+                .bind("2020-01-01T00:00:00Z")
+                .execute(pool)
+                .await
+                .unwrap();
+            shas.push(sha);
+        }
+        shas
+    }
+
+    /// Poll the persisted sweep cursor until it reaches `want`, or give up.
+    async fn cursor_reaches(db: &crate::db::Db, want: &str, within: Duration) -> String {
+        let deadline = std::time::Instant::now() + within;
+        loop {
+            let c = db.pin_repair_cursor().await.unwrap();
+            if c == want || std::time::Instant::now() >= deadline {
+                return c;
+            }
+            tokio::time::sleep(Duration::from_millis(20)).await;
+        }
+    }
+
+    /// #173 U4, the BOOT-PATH half. The sweep's own logic (batching, cursor resumption,
+    /// terminal vs retryable skips) is covered in `test_support`; what this covers is the
+    /// wiring `main` performs, which nothing else executes: the task is spawned at all,
+    /// it takes its batch and delay from the two `pin_repair_sweep_*` knobs rather than
+    /// some other config field, the caller is not blocked on the walk, and the shutdown
+    /// watcher ends the run mid-walk.
+    ///
+    /// Six scannable rows, batch 2, delay 30s. One pass must land the cursor on exactly
+    /// the second row and the task must then still be alive in its inter-batch sleep,
+    /// which pins both knobs at once: a different batch stops at a different row, and a
+    /// delay that did not come from the knob either finishes the table or leaves the task
+    /// gone. Shutdown must then end it while four rows are still unwalked.
+    #[sqlx::test]
+    async fn the_boot_path_spawns_the_sweep_detached_with_its_configured_knobs(pool: PgPool) {
+        let state = crate::test_support::test_state(pool.clone()).await;
+        let shas = seed_scannable_rows(&pool, 6).await;
+        let repos_dir = tempfile::TempDir::new().unwrap();
+
+        let mut config = (*state.config).clone();
+        config.repos_dir = repos_dir.path().to_path_buf();
+        config.pin_repair_sweep_batch = 2;
+        // Far longer than this test runs, so a task still alive after the first pass can
+        // only be one that is honoring the configured inter-batch delay.
+        config.pin_repair_sweep_delay_secs = 30;
+
+        let started = std::time::Instant::now();
+        let handle = spawn_legacy_cid_sweep(&state, &config);
+        let spawn_cost = started.elapsed();
+
+        let cursor = cursor_reaches(&state.db, &shas[1], Duration::from_secs(10)).await;
+        assert_eq!(
+            cursor, shas[1],
+            "the spawned sweep must run and stop its first pass at the CONFIGURED batch \
+             bound (2), leaving the cursor on the second row"
+        );
+        assert!(
+            spawn_cost < Duration::from_secs(1),
+            "the sweep must be detached, not awaited on the boot path; the spawn took \
+             {spawn_cost:?}"
+        );
+        assert!(
+            !handle.is_finished(),
+            "with a 30s inter-batch delay the task must still be sleeping between passes, \
+             not finished: a finished task means the delay was not the configured one"
+        );
+
+        state.shutdown();
+        tokio::time::timeout(Duration::from_secs(10), handle)
+            .await
+            .expect("the shutdown watcher must end the sweep, and not after its 30s delay")
+            .expect("the sweep task must not panic");
+
+        assert_eq!(
+            state.db.pin_repair_cursor().await.unwrap(),
+            shas[1],
+            "shutdown must have ended the run MID-walk, with the remaining rows unwalked"
+        );
+    }
+}
+
+#[cfg(test)]
+mod lock_pool_sizing_tests {
+    use super::{lock_pool_size, LOCK_POOL_MAX_CONNECTIONS, LOCK_POOL_PUSH_HEADROOM};
+
+    /// The default push cap gets its cap plus headroom, so no push ever queues for a
+    /// lock-pool connection where it did not before.
+    #[test]
+    fn default_push_cap_gets_headroom_over_the_cap() {
+        assert_eq!(lock_pool_size(32), 32 + u32::from(LOCK_POOL_PUSH_HEADROOM));
+        assert_eq!(lock_pool_size(1), 1 + u32::from(LOCK_POOL_PUSH_HEADROOM));
+    }
+
+    /// #173 F4: `max_concurrent_git_pushes` is validated all the way to 1_048_576, so an
+    /// operator raising it used to raise the node's Postgres connection ceiling with it,
+    /// silently and without bound. The lock pool is CLAMPED instead.
+    #[test]
+    fn an_oversized_push_cap_is_clamped_not_propagated() {
+        assert_eq!(lock_pool_size(1_048_576), LOCK_POOL_MAX_CONNECTIONS);
+        assert_eq!(lock_pool_size(usize::MAX), LOCK_POOL_MAX_CONNECTIONS);
+        // The largest cap that still fits under the clamp keeps its full headroom.
+        let widest = (LOCK_POOL_MAX_CONNECTIONS - u32::from(LOCK_POOL_PUSH_HEADROOM)) as usize;
+        assert_eq!(lock_pool_size(widest), LOCK_POOL_MAX_CONNECTIONS);
+        assert_eq!(
+            lock_pool_size(widest - 1),
+            LOCK_POOL_MAX_CONNECTIONS - 1,
+            "values below the clamp must not be rounded up to it"
+        );
+    }
+}
+
 #[cfg(test)]
 mod gossip_ssrf_tests {
    use super::ping_peer_health;
@@ -74,8 +74,10 @@ pub async fn pin_object(
 /// `..._fail_closed` filter on the full-scan path before calling. `repo_path` is
 /// still needed to read each object's bytes. The twin in `ipfs_pin.rs` mirrors
 /// this shape — change both in lockstep. Objects already recorded with a
-/// `pinata_cid` are skipped. Returns `(sha_hex, cid)` pairs for each newly
-/// pinned object.
+/// `pinata_cid` are skipped. `repo_id` records the pin's provenance (#173).
+/// Returns `(sha_hex, provider_cid)` pairs for each newly pinned object: the
+/// provider CID is the Pinata gateway CID (used for branch→CID recording and
+/// ref-update gossip), NOT the raw resolver-key CID stored in `pinned_cids.cid`.
 pub async fn pin_new_objects(
    client: &reqwest::Client,
    upload_url: &str,
@@ -83,6 +85,7 @@ pub async fn pin_new_objects(
    repo_path: &std::path::Path,
    object_list: Vec<String>,
    db: &crate::db::Db,
+    repo_id: &str,
 ) -> Vec<(String, String)> {
    if jwt.is_empty() {
        return vec![];
@@ -92,7 +95,39 @@ pub async fn pin_new_objects(

    for sha in object_list {
        match db.has_pinata_cid(&sha).await {
-            Ok(true) => continue,
+            Ok(true) => {
+                // Backfill NULL first-pinner provenance from a known source, in lockstep
+                // with the ipfs_pin skip branch: a pinata-only node otherwise leaves
+                // pre-provenance rows' `pinned_cids.repo_id` NULL forever (grok P2-D). The
+                // resolver still finds the object via the pin_repo_sources union below, so
+                // this is a consistency backfill, not a correctness fix.
+                match db.provenance_for_oid(&sha).await {
+                    Ok(None) => {
+                        if let Err(e) = db.backfill_pin_provenance(&sha, repo_id).await {
+                            tracing::warn!(sha = %sha, err = %e, "failed to backfill pin provenance");
+                        }
+                    }
+                    Ok(Some(_)) => {}
+                    Err(e) => {
+                        tracing::warn!(sha = %sha, err = %e, "DB error reading pin provenance");
+                    }
+                }
+                // F1 (#173 round 8): record this repo as an additional source for the
+                // already-pinned object (mirrors the ipfs_pin skip-branch insert) so the
+                // resolver can serve a shared object from any pin-path source. U3 (#173):
+                // retried through the SHARED helper (this was a bare call, so a single
+                // transient error dropped the source outright) and, on exhaustion, marked
+                // durably so the resolver keeps the bounded scan fallback for the object.
+                if let Err(e) =
+                    crate::ipfs_pin::retry_db_record(|| db.record_pin_source(&sha, repo_id)).await
+                {
+                    tracing::warn!(sha = %sha, err = %e, "failed to record pin source");
+                    if let Err(e) = db.mark_pin_sources_incomplete(&sha).await {
+                        tracing::warn!(sha = %sha, err = %e, "failed to mark pin sources incomplete");
+                    }
+                }
+                continue;
+            }
            Ok(false) => {}
            Err(e) => {
                tracing::warn!(sha = %sha, err = %e, "DB error checking pinata_cid");
@@ -111,9 +146,32 @@ pub async fn pin_new_objects(

        match pin_object(client, upload_url, jwt, &sha, &data).await {
            Ok(cid) if !cid.is_empty() => {
-                if let Err(e) = db.record_pinata_cid(&sha, &cid).await {
+                // The resolver key (`pinned_cids.cid`) must be the locally-computed
+                // raw-content CID, never the provider CID: Pinata wraps the bytes in
+                // dag-pb/UnixFS, so its returned CID does not hash the raw content and
+                // must not become an alias `/ipfs/{cid}` serves raw git bytes for (#173).
+                let raw_cid = gitlawb_core::cid::Cid::from_git_object_bytes(&data).to_string();
+                // U3 (#173): both records go through the shared retry helper, at parity
+                // with the ipfs_pin twin. These were bare calls, so one transient DB error
+                // permanently dropped a pin source.
+                if let Err(e) = crate::ipfs_pin::retry_db_record(|| {
+                    db.record_pinata_cid(&sha, &raw_cid, &cid, Some(repo_id))
+                })
+                .await
+                {
                    tracing::warn!(sha = %sha, err = %e, "failed to record pinata_cid in DB");
                }
+                // F1 (#173 round 8): also record the first pinner in pin_repo_sources.
+                // U3: an exhausted retry marks the set incomplete so the resolver keeps
+                // the scan fallback rather than 404ing a copy it could serve.
+                if let Err(e) =
+                    crate::ipfs_pin::retry_db_record(|| db.record_pin_source(&sha, repo_id)).await
+                {
+                    tracing::warn!(sha = %sha, err = %e, "failed to record pin source");
+                    if let Err(e) = db.mark_pin_sources_incomplete(&sha).await {
+                        tracing::warn!(sha = %sha, err = %e, "failed to mark pin sources incomplete");
+                    }
+                }
                pinned.push((sha, cid));
            }
            Ok(_) => {}
@@ -121,6 +121,28 @@ impl RateLimiter {
        true
    }

+    /// Non-consuming check: is this key ALREADY at its limit for the current window?
+    /// Unlike [`check`], it records nothing and never inserts a new key — used to shed
+    /// expensive preparatory work (e.g. the `/ipfs/{cid}` legacy scan's O(repos) DB
+    /// preload) BEFORE it runs, without perturbing the per-unit budget the consuming
+    /// `check` maintains (#173, F3). An unknown key or a disabled limiter is not
+    /// throttled. Prunes the key's expired timestamps as a side effect (keeps state
+    /// tidy) but adds none, so it cannot itself fill or grow the map.
+    pub(crate) async fn is_throttled(&self, key: &str) -> bool {
+        if self.max_requests == 0 {
+            return false;
+        }
+        let now = Instant::now();
+        let mut state = self.state.lock().await;
+        if let Some(window) = state.get_mut(key) {
+            window
+                .timestamps
+                .retain(|t| now.duration_since(*t) < self.window);
+            return window.timestamps.len() >= self.max_requests;
+        }
+        false
+    }
+
    pub async fn cleanup(&self) {
        let now = Instant::now();
        let mut state = self.state.lock().await;
@@ -130,6 +152,103 @@ impl RateLimiter {
            !w.timestamps.is_empty()
        });
    }
+
+    /// Number of distinct keys currently tracked. Test-only introspection so a
+    /// cross-module test can assert that a sweep actually evicted expired entries.
+    #[cfg(test)]
+    pub(crate) async fn tracked_keys(&self) -> usize {
+        self.state.lock().await.len()
+    }
+}
+
+/// A bounded per-caller CONCURRENCY limiter — distinct from [`RateLimiter`], which
+/// caps request RATE. Each caller key may hold at most `per_caller` in-flight
+/// permits at once; beyond that [`try_acquire`](Self::try_acquire) returns `None`
+/// and the caller sheds. Used to stop one caller (a single anonymous source-IP or
+/// DID) monopolizing the served-git read pool (#174).
+///
+/// The key map is self-bounding: a key is removed the instant its in-flight count
+/// reaches zero, so it never holds more keys than there are concurrently-active
+/// callers (itself bounded by the read semaphore). A `max_keys` reject-before-insert
+/// backstop guarantees a key farm can never grow the map even if that invariant
+/// weakened — a NEW key at the cap is rejected WITHOUT allocating an entry (INV-15).
+///
+/// Uses a `std::sync::Mutex` (not the file's `tokio::sync::Mutex`) because the
+/// permit's `Drop` must release synchronously; the critical section holds no await.
+#[derive(Clone)]
+pub struct PerCallerConcurrency {
+    state: Arc<std::sync::Mutex<HashMap<String, usize>>>,
+    per_caller: usize,
+    max_keys: usize,
+}
+
+/// RAII permit from [`PerCallerConcurrency::try_acquire`]. On drop it decrements
+/// the caller's in-flight count and removes the key when it reaches zero.
+pub struct PerCallerPermit {
+    state: Arc<std::sync::Mutex<HashMap<String, usize>>>,
+    key: String,
+}
+
+impl PerCallerConcurrency {
+    pub fn new(per_caller: usize, max_keys: usize) -> Self {
+        Self {
+            state: Arc::new(std::sync::Mutex::new(HashMap::new())),
+            per_caller: per_caller.max(1),
+            max_keys: max_keys.max(1),
+        }
+    }
+
+    /// Convenience constructor with the default key bound.
+    pub fn with_default_max_keys(per_caller: usize) -> Self {
+        Self::new(per_caller, DEFAULT_MAX_KEYS)
+    }
+
+    /// `Some(permit)` when the caller is under its cap and the map has room;
+    /// `None` (shed) otherwise. Reject-before-insert: a new key at `max_keys` is
+    /// rejected without allocating.
+    pub fn try_acquire(&self, key: &str) -> Option<PerCallerPermit> {
+        // Recover from a poisoned lock rather than panicking: the critical section
+        // is pure counter arithmetic and cannot itself panic, so a poisoned mutex
+        // would only ever come from an unrelated abort, and a slightly-off count
+        // self-heals as permits drop. A panic here would instead brick the limiter
+        // for every caller (each subsequent lock re-panics).
+        let mut map = self.state.lock().unwrap_or_else(|e| e.into_inner());
+        match map.get_mut(key) {
+            Some(count) => {
+                if *count >= self.per_caller {
+                    return None;
+                }
+                *count += 1;
+            }
+            None => {
+                if map.len() >= self.max_keys {
+                    return None;
+                }
+                map.insert(key.to_string(), 1);
+            }
+        }
+        Some(PerCallerPermit {
+            state: self.state.clone(),
+            key: key.to_string(),
+        })
+    }
+
+    #[cfg(test)]
+    pub fn tracked_keys(&self) -> usize {
+        self.state.lock().unwrap().len()
+    }
+}
+
+impl Drop for PerCallerPermit {
+    fn drop(&mut self) {
+        let mut map = self.state.lock().unwrap_or_else(|e| e.into_inner());
+        if let Some(count) = map.get_mut(&self.key) {
+            *count -= 1;
+            if *count == 0 {
+                map.remove(&self.key);
+            }
+        }
+    }
 }

 pub async fn rate_limit_by_did(request: Request, next: Next) -> Response {
@@ -250,12 +369,14 @@ impl<S: Send + Sync> axum::extract::FromRequestParts<S> for PeerAddr {
    }
 }

-/// The shared 429 response for the push flood brake.
+/// The shared 429 response for the per-IP flood brakes. Route-agnostic: this
+/// middleware now serves the push path AND the peer-sync routes, so the message
+/// stays generic (the offending path is recorded in the warn log below).
 pub fn too_many_requests() -> Response {
    (
        StatusCode::TOO_MANY_REQUESTS,
        [("retry-after", "60")],
-        "push rate limit exceeded — try again later",
+        "rate limit exceeded — try again later",
    )
        .into_response()
 }
@@ -273,7 +394,7 @@ pub async fn rate_limit_by_ip(request: Request, next: Next) -> Response {
    if let Some(limiter) = limiter {
        if let Some(key) = client_key(request.headers(), peer, limiter.trust) {
            if !limiter.limiter.check(&key).await {
-                tracing::warn!(key = %key, path = %request.uri().path(), "push rate limit exceeded");
+                tracing::warn!(key = %key, path = %request.uri().path(), "per-IP rate limit exceeded");
                return too_many_requests();
            }
        }
@@ -286,6 +407,63 @@ pub async fn rate_limit_by_ip(request: Request, next: Next) -> Response {
 mod tests {
    use super::*;

+    #[test]
+    fn per_caller_concurrency_caps_one_caller_and_frees_on_drop() {
+        let lim = PerCallerConcurrency::new(2, 100);
+        let p1 = lim.try_acquire("did:key:zA").expect("first under cap");
+        let p2 = lim.try_acquire("did:key:zA").expect("second under cap");
+        assert!(
+            lim.try_acquire("did:key:zA").is_none(),
+            "a third in-flight op for the same caller sheds (over the per-caller cap)"
+        );
+        // A DIFFERENT caller is unaffected — the cap is per-caller, not global.
+        let _other = lim
+            .try_acquire("did:key:zB")
+            .expect("a different caller has its own budget");
+        drop(p1);
+        assert!(
+            lim.try_acquire("did:key:zA").is_some(),
+            "freeing one in-flight slot lets the same caller back in"
+        );
+        drop(p2);
+    }
+
+    #[test]
+    fn per_caller_concurrency_map_is_self_bounding_and_reject_before_insert() {
+        // Self-bounding: acquire+drop many distinct keys — the map never grows
+        // because a key is removed the instant its in-flight count hits zero.
+        let lim = PerCallerConcurrency::new(4, 3);
+        for i in 0..50 {
+            let _p = lim.try_acquire(&format!("k{i}"));
+        }
+        assert_eq!(
+            lim.tracked_keys(),
+            0,
+            "keys with zero in-flight ops are removed, so an acquire+drop flood leaves the map empty"
+        );
+        // Reject-before-insert: HOLD max_keys distinct keys, then a new key sheds
+        // WITHOUT growing the map past the cap (INV-15 — a rejected request never
+        // allocates an entry).
+        let held: Vec<_> = (0..3)
+            .map(|i| lim.try_acquire(&format!("h{i}")).unwrap())
+            .collect();
+        assert_eq!(
+            lim.tracked_keys(),
+            3,
+            "three distinct callers held concurrently"
+        );
+        assert!(
+            lim.try_acquire("h3").is_none(),
+            "a new key at max_keys is rejected"
+        );
+        assert_eq!(
+            lim.tracked_keys(),
+            3,
+            "the rejected new key did not allocate an entry (reject-before-insert)"
+        );
+        drop(held);
+    }
+
    #[tokio::test]
    async fn allows_within_limit() {
        let limiter = RateLimiter::new(3, Duration::from_secs(60));
@@ -541,4 +719,66 @@ mod tests {
        assert_eq!(post_from(&router, b).await, StatusCode::OK); // independent bucket
        assert_eq!(post_from(&router, a).await, StatusCode::TOO_MANY_REQUESTS);
    }
+
+    // ── creation-route layering: IP brake runs BEFORE auth ──────────────
+
+    /// A minimal stand-in for the creation route group: an inner "auth" layer
+    /// that rejects every request with 401 (as signature verification would for
+    /// an unsigned caller), wrapped by the per-IP creation limiter as the
+    /// outermost layer — exactly the ordering `server::build_router` applies to
+    /// `/api/v1/repos` et al. Lets us assert the security-relevant property
+    /// (flood traffic is braked before auth burns CPU) without a database, which
+    /// the full `#[sqlx::test]` route test in `api::repos` cannot cover in the
+    /// plain unit-test pass.
+    fn ip_limited_over_auth_router(limiter: IpRateLimiter) -> axum::Router {
+        async fn always_unauthorized(_req: Request, _next: Next) -> Response {
+            StatusCode::UNAUTHORIZED.into_response()
+        }
+        axum::Router::new()
+            .route(
+                "/api/v1/repos",
+                axum::routing::post(|| async { StatusCode::CREATED }),
+            )
+            .layer(axum::middleware::from_fn(always_unauthorized))
+            .layer(axum::middleware::from_fn(rate_limit_by_ip))
+            .layer(axum::Extension(limiter))
+    }
+
+    async fn post_repos_from(router: &axum::Router, peer: SocketAddr) -> StatusCode {
+        use tower::ServiceExt;
+        let mut req = axum::http::Request::builder()
+            .method(axum::http::Method::POST)
+            .uri("/api/v1/repos")
+            .body(axum::body::Body::empty())
+            .unwrap();
+        req.extensions_mut().insert(ConnectInfo(peer));
+        router.clone().oneshot(req).await.unwrap().status()
+    }
+
+    #[tokio::test]
+    async fn creation_ip_brake_rejects_before_auth() {
+        // A DID farm mints a fresh signature per repo, so the per-DID limiter
+        // never trips; the per-IP brake is what stops the flood. It must run
+        // outermost, ahead of auth, so a flood is rejected with 429 before
+        // signature verification — otherwise every request would reach (and pay
+        // for) auth and merely 401.
+        let router = ip_limited_over_auth_router(IpRateLimiter {
+            limiter: RateLimiter::new(1, Duration::from_secs(60)),
+            trust: TrustedProxy::None,
+        });
+        let peer: SocketAddr = "203.0.113.42:7000".parse().unwrap();
+
+        // First request passes the IP brake and reaches the (failing) auth layer.
+        assert_eq!(
+            post_repos_from(&router, peer).await,
+            StatusCode::UNAUTHORIZED
+        );
+        // Budget now exhausted: the IP brake short-circuits with 429 *before*
+        // auth — proving the limiter is the outermost layer.
+        assert_eq!(
+            post_repos_from(&router, peer).await,
+            StatusCode::TOO_MANY_REQUESTS,
+            "an exhausted IP must be braked with 429 before auth runs, not leak to 401"
+        );
+    }
 }
@@ -81,8 +81,19 @@ pub fn build_router(state: AppState) -> Router {
        .route("/api/v1/tasks", get(tasks::list_tasks))
        .route("/api/v1/tasks/{id}", get(tasks::get_task));

-    // ── Rate-limited creation routes — require HTTP Signature + per-DID throttle
+    // ── Rate-limited creation routes — require HTTP Signature, plus a per-DID
+    // throttle AND a per-IP flood brake. The per-DID limiter (inner) caps a
+    // single identity; the per-IP limiter (outer) caps a DID farm that mints a
+    // fresh throwaway did:key per repo to slip past both the per-DID limit and
+    // the iCaptcha gate — the mechanism behind the recurring spam-repo floods.
+    // The per-IP layer wraps the auth layer (outermost = runs first) so flood
+    // traffic is rejected before signature verification burns CPU, matching the
+    // push path.
    let limiter = state.rate_limiter.clone();
+    let create_ip_limiter = rate_limit::IpRateLimiter {
+        limiter: state.create_ip_rate_limiter.clone(),
+        trust: state.push_limiter_trust,
+    };
    let creation_routes = add_auth_layers(
        Router::new()
            .route("/api/v1/repos", post(repos::create_repo))
@@ -96,7 +107,9 @@ pub fn build_router(state: AppState) -> Router {
            .layer(middleware::from_fn(rate_limit::rate_limit_by_did))
            .layer(axum::Extension(limiter)),
        state.clone(),
-    );
+    )
+    .layer(middleware::from_fn(rate_limit::rate_limit_by_ip))
+    .layer(axum::Extension(create_ip_limiter));

    // ── Write routes — require HTTP Signature (no rate limit) ─────────────
    let write_routes = add_auth_layers(
@@ -201,9 +214,20 @@ pub fn build_router(state: AppState) -> Router {
    // identity and can apply per-repo visibility (#110); anonymous callers stay
    // anonymous and still read genuinely public content. `/api/v1/ipfs/pins`
    // stays unsigned — gating the pin index is tracked separately (#121).
+    // `/ipfs/{cid}` also carries a per-IP flood brake: it is anon-reachable and each
+    // request can drive a full-history git walk, so the per-IP rate limiter is the
+    // outermost layer (rejects a flood before the walk-admission work), mirroring the
+    // push/create routers. The extension MUST be attached or rate_limit_by_ip is a
+    // silent no-op. `/api/v1/ipfs/pins` (no walk) is merged in unbraked, as before.
+    let ipfs_limiter = rate_limit::IpRateLimiter {
+        limiter: state.ipfs_rate_limiter.clone(),
+        trust: state.push_limiter_trust,
+    };
    let ipfs_routes = Router::new()
        .route("/ipfs/{cid}", get(ipfs::get_by_cid))
        .layer(middleware::from_fn(auth::optional_signature))
+        .layer(middleware::from_fn(rate_limit::rate_limit_by_ip))
+        .layer(axum::Extension(ipfs_limiter))
        .merge(Router::new().route("/api/v1/ipfs/pins", get(ipfs::list_pins)));

    // ── Arweave permanent anchors ──────────────────────────────────────────
@@ -248,7 +272,8 @@ pub fn build_router(state: AppState) -> Router {
        .route(
            "/api/v1/agents/{did}/bounties",
            get(bounties::agent_bounty_stats),
-        );
+        )
+        .layer(middleware::from_fn(auth::optional_signature));

    // ── Profile routes (write — require HTTP Signature) ─────────────────
    let profile_write_routes = add_auth_layers(
@@ -277,15 +302,41 @@ pub fn build_router(state: AppState) -> Router {
        .route("/api/v1/peers", get(peers::list_peers))
        .route("/api/v1/peers/{did}/ping", get(peers::ping_peer));

+    // /sync/trigger drives an O(peers) outbound fan-out + per-repo enqueue, so it
+    // ALWAYS requires a signature (both config modes) and carries a tight per-IP
+    // brake. A signature alone does not cap cost — a did:key farm self-registers
+    // (INV-10) — so the IP brake is a separate, load-bearing half. The brake is
+    // outermost (runs before signature verification burns CPU) and is keyed on the
+    // client IP before any DID is read, so DID rotation cannot bypass it.
+    let sync_trigger_routes = add_auth_layers(
+        Router::new().route("/api/v1/sync/trigger", post(peers::trigger_sync)),
+        state.clone(),
+    )
+    .layer(middleware::from_fn(rate_limit::rate_limit_by_ip))
+    .layer(axum::Extension(rate_limit::IpRateLimiter {
+        limiter: state.sync_trigger_rate_limiter.clone(),
+        trust: state.push_limiter_trust,
+    }));
+
+    // announce + notify keep their rolling-upgrade signature behavior (unsigned
+    // accepted until all peers upgrade), but both reach peer-write side effects —
+    // notify hits the same enqueue_sync sink as trigger — so they carry a per-IP
+    // brake too, on a SEPARATE bucket from trigger's, so an unsigned notify flood
+    // cannot drain the signed trigger caller's quota.
    let mut peer_write_routes = Router::new()
        .route("/api/v1/peers/announce", post(peers::announce))
-        .route("/api/v1/sync/trigger", post(peers::trigger_sync))
        .route("/api/v1/sync/notify", post(peers::notify_sync));
    peer_write_routes = if state.config.require_signed_peer_writes {
        add_auth_layers(peer_write_routes, state.clone())
    } else {
        peer_write_routes.layer(middleware::from_fn(auth::optional_signature))
    };
+    let peer_write_routes = peer_write_routes
+        .layer(middleware::from_fn(rate_limit::rate_limit_by_ip))
+        .layer(axum::Extension(rate_limit::IpRateLimiter {
+            limiter: state.peer_write_rate_limiter.clone(),
+            trust: state.push_limiter_trust,
+        }));

    // ── Read routes — open for public repos ───────────────────────────────
    let read_routes = Router::new()
@@ -415,6 +466,7 @@ pub fn build_router(state: AppState) -> Router {
    let meta_routes = Router::new()
        .route("/", get(node_info))
        .route("/health", get(health))
+        .route("/ready", get(ready))
        .route("/api/v1/p2p/info", get(p2p_info))
        .route("/api/v1/stats", get(stats))
        .route("/api/v1/contracts", get(contracts_info));
@@ -434,6 +486,7 @@ pub fn build_router(state: AppState) -> Router {
        .merge(read_routes)
        .merge(peer_read_routes)
        .merge(peer_write_routes)
+        .merge(sync_trigger_routes)
        .merge(ipfs_routes)
        .merge(arweave_routes)
        .merge(meta_routes)
@@ -456,6 +509,26 @@ async fn health() -> Json<serde_json::Value> {
    Json(json!({ "status": "ok" }))
 }

+/// Readiness = "this node can serve real traffic", and every real endpoint
+/// depends on the database, so probe it rather than reporting a constant.
+/// The probe gets its own short bound so a wedged pool can't hang the health
+/// check for the full acquire timeout.
+async fn ready(State(state): State<AppState>) -> axum::response::Response {
+    let probe = tokio::time::timeout(std::time::Duration::from_secs(2), state.db.ping()).await;
+    match probe {
+        Ok(Ok(())) => Json(json!({ "status": "ready" })).into_response(),
+        _ => (
+            axum::http::StatusCode::SERVICE_UNAVAILABLE,
+            Json(json!({
+                "status": "degraded",
+                "error": crate::error::DB_UNAVAILABLE_CODE,
+                "message": crate::error::DB_UNAVAILABLE_MESSAGE,
+            })),
+        )
+            .into_response(),
+    }
+}
+
 async fn node_info(State(state): State<AppState>) -> Json<serde_json::Value> {
    let p2p_peer_id = state.p2p.as_ref().map(|h| h.local_peer_id.to_string());
    Json(json!({
@@ -51,13 +51,74 @@ pub struct AppState {
    pub repo_store: RepoStore,
    /// Per-DID rate limiter for creation endpoints (repos, issues, PRs)
    pub rate_limiter: RateLimiter,
+    /// Per-client-IP rate limiter for the same creation endpoints. The per-DID
+    /// limiter above cannot brake a creation flood from a DID farm — one
+    /// throwaway `did:key` per repo means each DID makes a single create call
+    /// and never trips its own bucket. A valid iCaptcha proof does not cap this
+    /// either: the enforced level draws only machine-solvable deterministic
+    /// challenges (and the caller can pin the easy type), so a bot mints a fresh
+    /// DID, solves a proof, and creates a repo unthrottled. Braking on the
+    /// resolved client IP is what actually stops a single-source flood (same
+    /// rationale as `push_rate_limiter`). Keyed by `push_limiter_trust`.
+    pub create_ip_rate_limiter: RateLimiter,
    /// Per-client-IP rate limiter for git-receive-pack. Per-DID limits cannot
    /// brake a push flood from a DID farm (one throwaway DID per repo), so the
    /// push path throttles on the resolved client IP instead.
    pub push_rate_limiter: RateLimiter,
+    /// Per-client-IP ROUTE brake for `GET /ipfs/{cid}`: charged ONCE per request by the
+    /// `rate_limit_by_ip` middleware (server.rs), never inside the handler. It bounds
+    /// request RATE (the "requests per hour" contract of `GITLAWB_IPFS_RATE_LIMIT`) on
+    /// the non-farmable source IP, so an anonymous flood of the public route is capped.
+    /// The per-probe/per-walk WORK accounting the resolver does WITHIN a request draws
+    /// from the SEPARATE `ipfs_work_rate_limiter` below — the two cannot share one bucket
+    /// or a single request that spends a route token and then its own probe token off the
+    /// same bucket is admitted at the route and falsely shed mid-request (#173 round-10,
+    /// R6). Keyed by `push_limiter_trust`.
+    pub ipfs_rate_limiter: RateLimiter,
+    /// Per-client-IP WORK-budget limiter for the `GET /ipfs/{cid}` resolver's internal
+    /// fan-out: charged per legacy (NULL-provenance) PROBE (`acquire` + `cat-file`) and
+    /// per provenance-path WALK, and peeked non-consuming before the O(repos) legacy
+    /// preload. A legacy CID from the public pins index otherwise lets one request drive
+    /// O(repos) subprocess spawns and cold Tigris fetches, and repeat requests amplify
+    /// that across requests with zero limiter contact (INV-10, F3). Charging the work to
+    /// the non-farmable source IP bounds it. A bucket DISTINCT from the route brake above:
+    /// one request legitimately spends many work tokens (a full legacy scan is up to
+    /// `ipfs_max_legacy_probes` probes), so it must not double as the once-per-request
+    /// route bucket. Capacity is DERIVED from the route limit (`AppState::ipfs_work_budget`,
+    /// no separate operator knob), floored at the legacy-probe budget so a single default-
+    /// config deep search never self-throttles mid-scan. Keyed by `push_limiter_trust`.
+    pub ipfs_work_rate_limiter: RateLimiter,
+    /// Per-request ceiling on full-history reachability walks the CID resolver
+    /// may spawn (default `api::ipfs::MAX_HISTORY_WALKS_PER_REQUEST`). A field,
+    /// not a bare const, so tests can shrink it to exercise the cap cheaply;
+    /// production keeps the const default.
+    pub ipfs_max_history_walks: u32,
+    /// Per-request ceiling on legacy (NULL-provenance) repo probes in the CID
+    /// resolver's scan fallback (default `api::ipfs::MAX_LEGACY_PROBES_PER_REQUEST`).
+    /// Bounds the anonymous `acquire` + `cat-file` fan-out across the node (#173,
+    /// INV-10); a field for the same test-seam reason as `ipfs_max_history_walks`.
+    pub ipfs_max_legacy_probes: u32,
+    /// Hard ceiling on the byte size of an object `GET /ipfs/{cid}` will buffer and
+    /// serve (default `api::ipfs::MAX_SERVED_OBJECT_BYTES`). The serve reads via a
+    /// blocking `git cat-file` and buffers the whole object; without a bound a large
+    /// public blob could exhaust memory or block a runtime worker (#173, F6, INV-10).
+    /// A field for the same test-seam reason as the sibling caps.
+    pub ipfs_max_served_object_bytes: u64,
    /// Which forwarded header (if any) the edge is trusted to set, for
    /// resolving the push limiter's client-IP key. See `GITLAWB_TRUSTED_PROXY`.
+    /// Node-wide; also keys the two peer-sync limiters below.
    pub push_limiter_trust: crate::rate_limit::TrustedProxy,
+    /// Per-client-IP limiter for `POST /api/v1/sync/trigger` (tight). The route
+    /// requires a signature, but a signature does not cap cost (a did:key farm
+    /// self-registers), and its per-call cost is an O(peers) fan-out, so the IP
+    /// brake is a separate, load-bearing half. Its own bucket so an unsigned
+    /// `/sync/notify` flood cannot drain the signed trigger caller's quota.
+    pub sync_trigger_rate_limiter: RateLimiter,
+    /// Per-client-IP limiter for the peer-write routes (`/peers/announce`,
+    /// `/sync/notify`) (generous). `/sync/notify` reaches the same `enqueue_sync`
+    /// sink as trigger and accepts unsigned requests from known peers, so it is
+    /// braked too; each peer's distinct IP gets its own bucket.
+    pub peer_write_rate_limiter: RateLimiter,
    /// Process-wide graceful-shutdown signal. Sending `true` causes every
    /// task that holds a `watch::Receiver` to exit at its next await point.
    /// Used by:
@@ -66,6 +127,94 @@ pub struct AppState {
    ///   * the libp2p swarm task
    ///   * the gossip, sync, operator heartbeat, and rate-limit cleanup loops
    pub shutdown_tx: tokio::sync::watch::Sender<bool>,
+    /// Bounds concurrent served git READ operations (upload-pack + both info/refs
+    /// advertisements). A read handler acquires a permit before spawning git and
+    /// holds it for the op; when none are free the request is shed with a 503.
+    /// Writes draw from `git_write_semaphore` so a read flood cannot shed an
+    /// authenticated push at admission (#174).
+    pub git_read_semaphore: Arc<tokio::sync::Semaphore>,
+    /// Bounds concurrent `git-receive-pack` (push) operations, a pool separate
+    /// from `git_read_semaphore` so an anonymous READ flood can never shed an
+    /// authenticated push (#174). Sized by `max_concurrent_git_pushes`. Drawn from
+    /// by the `git-receive-pack` POST (owner-gated) ONLY. The anon-reachable
+    /// receive-pack `info/refs` advertisement draws from the SEPARATE
+    /// `git_push_advert_semaphore` below, never this pool, so a multi-source flood
+    /// of push-handshake advertisements can never occupy a permit an authenticated
+    /// POST needs at admission (#174).
+    pub git_write_semaphore: Arc<tokio::sync::Semaphore>,
+    /// Bounds concurrent anon-reachable `git-receive-pack` `info/refs`
+    /// advertisements — a pool SEPARATE from `git_write_semaphore` so adverts (which
+    /// hold a permit across `acquire_fresh` + `info/refs`) can never consume a slot
+    /// the authenticated POST relies on. A per-source flood can at worst exhaust this
+    /// advert pool (each source also capped by `git_push_advert_per_caller` and the
+    /// per-IP push rate limiter), and the reserved POST pool is untouched (#174).
+    pub git_push_advert_semaphore: Arc<tokio::sync::Semaphore>,
+    /// Bounds concurrent post-push encrypt-then-pin history walks. Each successful
+    /// path-scoped push releases its handler write permit and then runs a DETACHED
+    /// full-history walk (`withheld_blob_recipients_bounded`) to seal withheld blobs;
+    /// without a cap, N fast pushes spawn N concurrent full-history git walks past
+    /// `max_concurrent_git_pushes` (which only bounds the in-handler phase). The walk
+    /// acquires a permit here and DEFERS (blocks) when the pool is full rather than
+    /// shedding — the work is background and dropping it would lose the recovery copy
+    /// (#174 P1-e). A pool of its own, not `git_write_semaphore`: a long background
+    /// walk must not hold a foreground write slot, and a handler already holding a
+    /// write permit that needed a second would self-deadlock at pool size 1.
+    pub git_encrypt_semaphore: Arc<tokio::sync::Semaphore>,
+    /// Bounds the OUTSTANDING post-push encryption-task set by per-repo coalescing
+    /// (#174 P2-2). `git_encrypt_semaphore` caps *active* walks; this caps how many
+    /// detached tasks *spawn and park* on that semaphore's `acquire_owned().await`.
+    /// Before spawning a per-push encryption task, the receive-pack handler consults
+    /// this set: if the repo already has a task in flight it coalesces (skips the
+    /// duplicate spawn) rather than parking a new unbounded waiter. Coalescing only
+    /// delays a duplicate walk — it never drops the withheld-blob recovery copy, which
+    /// `2a54c15` deliberately kept fail-closed (there is no reconciliation sweep to
+    /// re-derive a dropped copy). See [`EncryptInflight`].
+    pub encrypt_inflight: EncryptInflight,
+    /// Per-caller concurrency sub-cap on the read pool: each caller (keyed on the
+    /// resolved source IP, #174 U1) may hold at most `max_concurrent_reads_per_caller`
+    /// in-flight read ops, so one caller cannot monopolize `git_read_semaphore`
+    /// (#174). Applied by `git_upload_pack` and the upload-pack `info/refs`
+    /// advertisement.
+    pub git_read_per_caller: crate::rate_limit::PerCallerConcurrency,
+    /// Per-source concurrency sub-cap on the anon-reachable receive-pack `info/refs`
+    /// advertisement: each source IP may hold at most a small share of the write
+    /// pool, so a multi-source flood of push-handshake advertisements cannot
+    /// saturate `git_write_semaphore` and shed authenticated pushes (#174). Sized as
+    /// a fraction of `max_concurrent_git_pushes`, so filling the write pool takes many
+    /// distinct source IPs (each also braked by the per-IP push rate limiter).
+    pub git_push_advert_per_caller: crate::rate_limit::PerCallerConcurrency,
+    /// Per-source concurrency sub-cap on the authenticated `git-receive-pack` POST:
+    /// each source IP may hold at most a small share of `git_write_semaphore`, so one
+    /// host minting disposable `did:key` identities cannot open enough slow pushes to
+    /// monopolize the write pool and 503 every other source's push (#174 P1-d). Keyed
+    /// on the resolved source IP (never the DID — a DID farm defeats a DID key). Sized
+    /// like `git_push_advert_per_caller`, a fraction of `max_concurrent_git_pushes`.
+    pub git_write_per_caller: crate::rate_limit::PerCallerConcurrency,
+    /// Bounds concurrent `GET /ipfs/{cid}` visibility-walk requests. The public
+    /// `/ipfs/{cid}` route runs `allowed_blob_set_for_caller_bounded` in
+    /// `spawn_blocking` (a full-history git walk) with NO served-git admission of its
+    /// own; without this a permissionless caller fans out concurrent walks past every
+    /// git pool, exhausting the blocking pool + PIDs (#174 P1-3). A request acquires a
+    /// permit before the repo loop and holds it for the whole request (across every
+    /// `spawn_blocking` walk), so the slot reflects real thread occupancy — a tokio
+    /// walk-timeout cannot free it while the blocking work still runs. A pool of its
+    /// own (`max_concurrent_ipfs_walks`), NOT a git pool: distinct cost center + public
+    /// surface, so anonymous /ipfs traffic can never shed an authenticated git op.
+    pub git_ipfs_walk_semaphore: Arc<tokio::sync::Semaphore>,
+    /// Per-source concurrency sub-cap on the `/ipfs/{cid}` walk pool: each source
+    /// (keyed on the resolved source IP, never the DID — `/ipfs` admits any `did:key`
+    /// unthrottled, so a DID key would be free to mint around) may hold at most
+    /// `ipfs_walk_per_source` in-flight walk slots, so one source cannot monopolize
+    /// `git_ipfs_walk_semaphore` (#174 P1-3). A request with no resolvable key is
+    /// bounded by the global pool only, never this sub-cap. The key map is bounded
+    /// (`with_default_max_keys`, reject-before-insert) so a source-key farm cannot grow
+    /// it (INV-15).
+    pub git_ipfs_walk_per_caller: crate::rate_limit::PerCallerConcurrency,
+    /// The `git` executable the served-git withheld-blob walk spawns. Production is
+    /// `"git"` (resolved via PATH); injectable so a fake `git` can drive the walk's
+    /// process-group teardown in handler tests without mutating the process-global
+    /// PATH (#174).
+    pub git_bin: String,
 }

 impl AppState {
@@ -75,6 +224,21 @@ impl AppState {
        self.shutdown_tx.subscribe()
    }

+    /// Sweep expired entries from every per-IP/DID rate limiter. Driven by the
+    /// periodic cleanup task so a bounded limiter's key map sheds stale entries
+    /// instead of sitting near its cap until an inline capacity sweep reclaims
+    /// them. Every limiter on the state is swept here; adding a new limiter means
+    /// adding it to this list.
+    pub(crate) async fn sweep_rate_limiters(&self) {
+        self.rate_limiter.cleanup().await;
+        self.create_ip_rate_limiter.cleanup().await;
+        self.push_rate_limiter.cleanup().await;
+        self.ipfs_rate_limiter.cleanup().await;
+        self.ipfs_work_rate_limiter.cleanup().await;
+        self.sync_trigger_rate_limiter.cleanup().await;
+        self.peer_write_rate_limiter.cleanup().await;
+    }
+
    /// Trigger graceful shutdown. Idempotent — calling more than once
    /// has no effect. Returns `true` if this call was the one that
    /// flipped the signal.
@@ -95,4 +259,173 @@ impl AppState {
    pub fn is_shutting_down(&self) -> bool {
        *self.shutdown_tx.borrow()
    }
+
+    /// Legacy-probe budget wired from the `GITLAWB_IPFS_MAX_REPOS_WALKED` operator
+    /// knob (R5, KTD5). The knob seeds `ipfs_max_legacy_probes` at construction so it
+    /// controls the per-request legacy (NULL-provenance) probe fan-out it advertises.
+    /// It deliberately does NOT feed `ipfs_max_history_walks`: that ceiling must stay
+    /// at `MAX_HISTORY_WALKS_PER_REQUEST` (`MAX_PIN_SOURCES + 1`) or a provenanced
+    /// request with a full source set is truncated into a false 503, and the knob's
+    /// range starts at 1. The knob is `usize`, the field `u32`; the range cap
+    /// (1_048_576) keeps the cast lossless.
+    pub(crate) fn ipfs_legacy_probe_budget(config: &crate::config::Config) -> u32 {
+        config.ipfs_max_repos_walked as u32
+    }
+
+    /// Work-budget capacity for [`ipfs_work_rate_limiter`](Self#structfield.ipfs_work_rate_limiter)
+    /// (R6, KTD6), DERIVED from the route limit rather than a new operator knob. The route
+    /// limiter (`ipfs_rate_limiter`) charges once per request; this separate bucket absorbs
+    /// the resolver's per-probe/per-walk work charges so both the route "requests per hour"
+    /// contract and the amplification bound hold. Floor: at least one full legacy search per
+    /// window — the effective `ipfs_max_legacy_probes` (the `GITLAWB_IPFS_MAX_REPOS_WALKED`
+    /// knob, U4) — so a single default-config deep search cannot self-throttle mid-scan and
+    /// recreate the F6 admit-then-429 for a legitimate caller. `GITLAWB_IPFS_RATE_LIMIT=0`
+    /// disables the route brake and this derived bucket alike (a 0-capacity limiter admits
+    /// everything).
+    pub(crate) fn ipfs_work_budget(config: &crate::config::Config) -> usize {
+        if config.ipfs_rate_limit == 0 {
+            return 0;
+        }
+        config.ipfs_rate_limit.max(config.ipfs_max_repos_walked)
+    }
+}
+
+/// Bounds the OUTSTANDING post-push encryption-task set by per-repo coalescing
+/// (#174 P2-2). Each successful path-scoped push `tokio::spawn`s a DETACHED task that
+/// parks on `git_encrypt_semaphore.acquire_owned().await` (which DEFERS when the pool
+/// is full rather than shedding — `2a54c15` kept it fail-closed so the withheld-blob
+/// recovery copy is never dropped). The semaphore caps *active* walks, but nothing
+/// capped how many detached tasks *spawn and park* on that await: N rapid pushes to a
+/// repo spawn N parked tasks, each holding cloned object lists/rules/paths/keys — an
+/// unbounded outstanding set.
+///
+/// This tracks the repo keys with an in-flight encryption task, each carrying a
+/// DIRTY flag. Before spawning, the handler calls [`try_begin`](Self::try_begin): if
+/// a task for the repo is already in-flight it MARKS THE REPO DIRTY and returns `None`
+/// so the handler SKIPS spawning a duplicate (coalesce). The in-flight task consults
+/// the flag at its tail via [`requeue_or_release`](EncryptInflightGuard::requeue_or_release):
+/// a set flag makes it run ONE MORE pass (re-reading repo state) before it exits, so a
+/// push coalesced during the in-flight window is REQUEUED, never dropped. This bounds
+/// the outstanding set to <=1 task per repo without losing work: there is no
+/// reconciliation sweep, so a *dropped* job would be lost forever.
+///
+/// The returned [`EncryptInflightGuard`] is moved into the detached task. The normal
+/// exit path is `requeue_or_release`, which removes the repo key ATOMICALLY with the
+/// "clean" decision — no push can land in the gap between "checked clean" and "task
+/// exits". `Drop` is a panic backstop only: if the task panics (or returns without
+/// calling `requeue_or_release`) it still removes the key so a crashed walk can never
+/// permanently lock a repo out of future recovery copies.
+#[derive(Clone, Default)]
+pub struct EncryptInflight {
+    // std::sync::Mutex: only ever held for O(1) HashMap ops in a sync context (before
+    // `tokio::spawn`, at the task tail, and in Drop) — never across an await, so a std
+    // Mutex is correct and cheaper than a tokio one. The value is the DIRTY flag: a
+    // coalesced push flips it true so the in-flight task requeues one more pass.
+    repos: Arc<std::sync::Mutex<std::collections::HashMap<String, bool>>>,
+}
+
+impl EncryptInflight {
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Try to begin an encryption task for `repo_id`. Returns `Some(guard)` if no task
+    /// for the repo was in-flight (the caller should spawn). If one already is, MARKS
+    /// the repo dirty and returns `None` (the caller COALESCES — skips the duplicate
+    /// spawn; the in-flight task requeues one more pass to cover this push).
+    pub fn try_begin(&self, repo_id: &str) -> Option<EncryptInflightGuard> {
+        let mut map = self.repos.lock().expect("encrypt_inflight mutex poisoned");
+        match map.get_mut(repo_id) {
+            Some(dirty) => {
+                *dirty = true;
+                None
+            }
+            None => {
+                map.insert(repo_id.to_string(), false);
+                Some(EncryptInflightGuard {
+                    repos: Arc::clone(&self.repos),
+                    repo_id: repo_id.to_string(),
+                    released: false,
+                })
+            }
+        }
+    }
+
+    /// Number of repos with an in-flight encryption task. Test/metrics observability;
+    /// the bound under saturation is `len() <= number of distinct repos`, i.e. at most
+    /// one task per repo.
+    #[allow(dead_code)]
+    pub fn len(&self) -> usize {
+        self.repos
+            .lock()
+            .expect("encrypt_inflight mutex poisoned")
+            .len()
+    }
+
+    #[allow(dead_code)]
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+
+    /// Test-only: read the dirty flag for `repo_id` (`None` if no task is in-flight).
+    #[cfg(test)]
+    pub fn dirty(&self, repo_id: &str) -> Option<bool> {
+        self.repos
+            .lock()
+            .expect("encrypt_inflight mutex poisoned")
+            .get(repo_id)
+            .copied()
+    }
+}
+
+/// RAII guard for one in-flight encryption task's repo key. The task drives it at its
+/// tail with [`requeue_or_release`](Self::requeue_or_release); `Drop` is a panic
+/// backstop. Move-only — cloning would double-release.
+pub struct EncryptInflightGuard {
+    repos: Arc<std::sync::Mutex<std::collections::HashMap<String, bool>>>,
+    repo_id: String,
+    released: bool,
+}
+
+impl EncryptInflightGuard {
+    /// TASK-TAIL check-and-clear, atomic with the release decision. If a push
+    /// coalesced since the last pass (dirty), clear the flag and return `true` (the
+    /// task loops one more pass). Otherwise remove the key and return `false` (the task
+    /// exits). Atomic under the mutex: a concurrent push either sets the flag BEFORE
+    /// this reads it (-> requeue covers it) or arrives AFTER the key is removed (-> a
+    /// fresh `try_begin` spawns a new task) — there is no window where the key is
+    /// present-but-clean while the task exits.
+    pub fn requeue_or_release(&mut self) -> bool {
+        let mut map = self.repos.lock().expect("encrypt_inflight mutex poisoned");
+        match map.get_mut(&self.repo_id) {
+            Some(dirty) if *dirty => {
+                *dirty = false;
+                true
+            }
+            _ => {
+                map.remove(&self.repo_id);
+                self.released = true;
+                false
+            }
+        }
+    }
+}
+
+impl Drop for EncryptInflightGuard {
+    fn drop(&mut self) {
+        // Panic backstop ONLY. The normal exit is `requeue_or_release` (which removed
+        // the key atomically and set `released`), so this does nothing then. If the
+        // task panicked or returned without releasing, remove the key so one crashed
+        // walk never permanently locks the repo out.
+        //
+        // Accepted residual: a panic with the dirty flag still set drops the requeued
+        // work — Drop cannot loop — the same loss class as the on-panic behavior before
+        // this change. No reconciliation sweep re-derives it.
+        if self.released {
+            return;
+        }
+        if let Ok(mut map) = self.repos.lock() {
+            map.remove(&self.repo_id);
+        }
+    }
 }
@@ -25,15 +25,12 @@ fn nfc(s: &str) -> String {
    s.nfc().collect()
 }

-/// True if `caller` is the repo owner. Matches exactly or against the
-/// did:key short form — a non-key DID (did:gitlawb:/did:web:) in `owner_did`
-/// never matches a bare short segment, and a non-key DID in `caller` never
-/// matches a did:key owner's short form. Uses `normalize_owner_key` (not
-/// `did_matches`) so the did:key-only rule is stricter: cross-method matching
-/// would let a non-key canonical row bypass the #124 visibility gate.
+/// True if `caller` is the repo owner. Uses [`crate::api::did_matches`] so the
+/// owner check is representation-agnostic within `did:key` (full `did:key:z...`
+/// matches bare `z...` stored by mirror rows) while still denying cross-method
+/// collisions (`did:gitlawb:z...` vs bare `z...`).
 fn is_owner(owner_did: &str, caller: &str) -> bool {
-    let owner_short = crate::db::normalize_owner_key(owner_did);
-    caller == owner_did || caller == owner_short
+    crate::api::did_matches(owner_did, caller)
 }

 /// The match prefix for a glob: "/" stays "/", "/secret/**" becomes "/secret".
@@ -428,6 +425,60 @@ mod tests {
        );
    }

+    // #153 forward guard: is_owner must match across bare-key / full-did:key
+    // representations should someone revert to single-side normalize_owner_key.
+    #[test]
+    fn bare_owner_full_caller_allows_owner() {
+        let rules = [rule("/", VisibilityMode::A, &[])];
+        assert_eq!(
+            visibility_check(&rules, false, "z6MkOwner", Some("did:key:z6MkOwner"), "/"),
+            Decision::Allow,
+            "bare owner + full did:key caller must match (guard against single-side revert)"
+        );
+    }
+
+    // #135 T1: a Mode-B rule on `/secret/**` must DENY the withheld directory's
+    // OWN path `/secret` (the `path == prefix` arm), not just strict descendants —
+    // otherwise get_by_cid's tree gate would serve the /secret tree object and leak
+    // its children. Pins parity with get_tree, which denies the /secret path.
+    #[test]
+    fn subtree_rule_denies_the_withheld_directory_itself() {
+        let reader = "did:key:z6MkReader";
+        let rules = [rule("/secret/**", VisibilityMode::B, &[reader])];
+        assert_eq!(
+            visibility_check(&rules, true, OWNER, None, "/secret"),
+            Decision::Deny,
+            "anon denied at the withheld directory's OWN path /secret"
+        );
+        assert_eq!(
+            visibility_check(&rules, true, OWNER, None, "/public"),
+            Decision::Allow,
+            "anon allowed at a sibling path outside the withheld subtree"
+        );
+        assert_eq!(
+            visibility_check(&rules, true, OWNER, Some(reader), "/secret"),
+            Decision::Allow,
+            "listed reader allowed at the withheld directory (caller-aware)"
+        );
+    }
+
+    // #153 regression: cross-method DID must still be denied even when the
+    // trailing segment collides with a bare owner key.
+    #[test]
+    fn cross_method_did_denied_with_bare_owner() {
+        let rules = [rule("/", VisibilityMode::A, &[])];
+        assert_eq!(
+            visibility_check(&rules, false, "z6MkFoo", Some("did:gitlawb:z6MkFoo"), "/"),
+            Decision::Deny,
+            "cross-method DID must not match a bare did:key owner"
+        );
+        assert_eq!(
+            visibility_check(&rules, false, "z6MkFoo", Some("did:web:z6MkFoo"), "/"),
+            Decision::Deny,
+            "did:web must not match a bare did:key owner"
+        );
+    }
+
    #[test]
    fn root_rule_allows_listed_reader() {
        let rules = [rule("/", VisibilityMode::A, &["did:key:z6MkFriend"])];
@@ -0,0 +1,139 @@
+//! #174 U6 — INV-22 completeness guard (rung-raising).
+//!
+//! INV-22: a permit held per op recovers only if every path that holds it is also
+//! duration-bounded and reaps the process group before releasing admission, and every
+//! detached git/blocking task carries its own admission. PR #174 fixed five paths
+//! (U1-U5) that violated this. Each fix has a per-unit RED/GREEN regression; together
+//! those form the five-revert matrix. This guard adds the missing piece: a source-scan
+//! tripwire that fails when a NEW site reintroduces the class, or when one of the five
+//! gates is removed.
+//!
+//! It lives in `tests/` (a separate crate) on purpose: a guard that scanned the same
+//! file it lives in would match its own identifier literals and pass vacuously. Here
+//! the scanned `src/` files never contain this file's literals, so each check is
+//! load-bearing — reverting the named gate turns the assertion red.
+//!
+//! These are deliberately coarse structural checks, not a parser. They cannot prove a
+//! gate is *correct* (the per-unit tests do that); they prove a gate is *present and
+//! not bypassed*, which is what stops the class from silently regressing.
+
+use std::path::Path;
+
+fn src(rel: &str) -> String {
+    let p = Path::new(env!("CARGO_MANIFEST_DIR")).join("src").join(rel);
+    std::fs::read_to_string(&p).unwrap_or_else(|e| panic!("read {}: {e}", p.display()))
+}
+
+#[test]
+fn inv22_concurrency_gates_present_and_not_bypassed() {
+    let repos = src("api/repos.rs");
+    let smart_http = src("git/smart_http.rs");
+    let vis = src("git/visibility_pack.rs");
+    let ipfs = src("api/ipfs.rs");
+
+    // U1 / P1-a: run_bounded_git stands the watchdog down only after confirming the
+    // child actually terminated (WNOWAIT), not on the raw stdout-drain EOF — otherwise
+    // a child that closes stdout then hangs pins the permit past the deadline. The
+    // probe is defined and called, so >= 2 occurrences; reverting the fix removes both.
+    assert!(
+        vis.matches("child_terminated_without_reaping").count() >= 2,
+        "U1/P1-a gate missing: run_bounded_git must confirm child exit via \
+         child_terminated_without_reaping before signalling the watchdog"
+    );
+
+    // U2 / P1-c: on client disconnect KillGroupOnDrop must launch a detached reaper
+    // that runs the full TERM/grace/KILL/reap, not a lone SIGTERM. The reaper is spawned
+    // via a runtime handle in Drop; `Handle::try_current` is unique to that launch (the
+    // timeout path already has an async context and never calls it).
+    assert!(
+        smart_http.contains("Handle::try_current"),
+        "U2/P1-c gate missing: KillGroupOnDrop::drop must launch the full \
+         TERM/grace/KILL reaper on disconnect (Handle::try_current), not a lone SIGTERM"
+    );
+
+    // U4 / P1-d: git_receive_pack must acquire the per-source write sub-cap before the
+    // global write permit. The acquire reads `state.git_write_per_caller`; comments name
+    // the field without the `state.` prefix, so this targets the real acquire site.
+    assert!(
+        repos.contains("state.git_write_per_caller"),
+        "U4/P1-d gate missing: git_receive_pack must acquire the per-source write cap \
+         (state.git_write_per_caller) before the global write permit"
+    );
+
+    // U5 / P1-e: the detached post-push encryption walk must run through the
+    // admission-gated helper, which is wired to the shared encrypt pool.
+    assert!(
+        repos.contains("fn withheld_recipients_gated")
+            && repos.contains("state.git_encrypt_semaphore"),
+        "U5/P1-e gate missing: the encryption walk must run through \
+         withheld_recipients_gated, which acquires git_encrypt_semaphore"
+    );
+
+    // U1 / R2 (#173 round-10): the path-scoped filtered-pack serve must thread the
+    // caller's AdmissionGuard through BOTH git stages so read + per-caller admission is
+    // held until the pack-objects group is reaped on disconnect, closing the cap bypass
+    // the plain upload_pack path already fixed. Two load-bearing markers: rev-list hands
+    // the disarmed guard back (its tuple return type), and build_filtered_pack forwards
+    // that guard into the pack-objects stage (the `admission` arg after the
+    // "pack-objects" label). Reverting either — dropping the guard between stages, or
+    // passing `None` to pack-objects — trips this.
+    assert!(
+        smart_http.contains("Result<(Vec<String>, Option<AdmissionGuard>)>")
+            && smart_http.contains("\"pack-objects\",\n        admission,"),
+        "U1/R2 gate missing: build_filtered_pack must thread the AdmissionGuard through \
+         rev-list -> pack-objects so the permits are held until the pack-objects group \
+         is reaped on disconnect (the path-scoped half of #174 P1-a)"
+    );
+
+    // U2 / R1 (#173 round-10): the `GET /ipfs/{cid}` serve pipeline must run in a
+    // DETACHED tokio task that OWNS the AdmissionGuard built from BOTH walk permits, so a
+    // cancelled or timed-out request releases admission only after the spawned (bounded)
+    // work completes — not the instant the handler future drops (the /ipfs half of #174
+    // P1-a). Two load-bearing markers: the guard is constructed from the two named
+    // permits, and the whole pipeline is moved into a `tokio::spawn`. Reverting to
+    // handler-local permits (dropping the guard/spawn) trips this.
+    assert!(
+        ipfs.contains("AdmissionGuard::new(ipfs_walk_permit, ipfs_caller_permit)")
+            && ipfs.contains(
+                "let serve: tokio::task::JoinHandle<Result<Response>> = tokio::spawn(async move {"
+            ),
+        "U2/R1 gate missing: get_by_cid must move both /ipfs admission permits into an \
+         AdmissionGuard owned by a detached tokio::spawn task so admission is released \
+         only after the spawned serve work completes (the /ipfs half of #174 P1-a)"
+    );
+
+    // U2 / KTD2 (#173 round-10): the probe/read children on the /ipfs path must be the
+    // duration-bounded twins (process-group teardown via run_bounded_git), not the bare
+    // `store::object_type` / `read_object_content` (or an unbounded `cat-file -s`) a tokio
+    // timeout cannot cancel — otherwise a wedged cat-file lingers and pins the held
+    // admission past the deadline. Reverting any twin call site back to a bare read trips
+    // this.
+    assert!(
+        ipfs.contains("object_type_bounded(")
+            && ipfs.contains("object_size_bounded(")
+            && ipfs.contains("read_object_content_bounded("),
+        "U2/KTD2 gate missing: the /ipfs probe+read must call the run_bounded_git-backed \
+         *_bounded twins so a wedged cat-file is reaped at the deadline, not left to pin \
+         the held /ipfs walk admission"
+    );
+
+    // P1-e non-bypass tripwire: the bounded recipients walk is spawn_blocking'd nowhere
+    // but inside withheld_recipients_gated. A second call site (count > 1) is a new
+    // detached git walk that skips the admission gate — exactly the class U5 closed.
+    assert_eq!(
+        repos.matches("withheld_blob_recipients_bounded").count(),
+        1,
+        "P1-e bypass: the bounded recipients walk must be invoked only inside \
+         withheld_recipients_gated; a new call site bypasses the encrypt-walk admission cap"
+    );
+
+    // U4 / P2-2: the detached post-push encryption task must be gated by the per-repo
+    // coalescing set (`encrypt_inflight.try_begin`) so the OUTSTANDING parked-task set is
+    // bounded to <=1 per repo. Removing the gate lets N rapid pushes spawn N parked
+    // waiters (the unbounded set U4 closed); the semaphore only caps active walks.
+    assert!(
+        repos.contains("state.encrypt_inflight.try_begin"),
+        "U4/P2-2 gate missing: the detached post-push encryption spawn must consult \
+         encrypt_inflight.try_begin to coalesce per repo (bound the outstanding-task set)"
+    );
+}
@@ -1,7 +1,7 @@
 [package]
 name = "gl"
 description = "The gitlawb CLI — identity management, node control, MCP server"
-version = "0.5.0" # x-release-please-version
+version = "0.5.1" # x-release-please-version
 edition.workspace = true
 rust-version.workspace = true
 license.workspace = true
@@ -8,6 +8,10 @@ use std::path::PathBuf;
 use crate::http::NodeClient;
 use crate::identity::load_keypair_from_dir;

+fn signed_client(node: &str, dir: Option<&std::path::Path>) -> NodeClient {
+    NodeClient::new(node, load_keypair_from_dir(dir).ok())
+}
+
 #[derive(Args)]
 pub struct BountyArgs {
    #[command(subcommand)]
@@ -49,6 +53,8 @@ pub enum BountyCmd {
        status: Option<String>,
        #[arg(long, default_value = "https://node.gitlawb.com", env = "GITLAWB_NODE")]
        node: String,
+        #[arg(long)]
+        dir: Option<PathBuf>,
    },
    /// Show details of a specific bounty
    Show {
@@ -56,6 +62,8 @@ pub enum BountyCmd {
        id: String,
        #[arg(long, default_value = "https://node.gitlawb.com", env = "GITLAWB_NODE")]
        node: String,
+        #[arg(long)]
+        dir: Option<PathBuf>,
    },
    /// Claim an open bounty
    Claim {
@@ -121,8 +129,13 @@ pub async fn run(args: BountyArgs) -> Result<()> {
            node,
            dir,
        } => cmd_create(repo, title, amount, issue, tx_hash, deadline, node, dir).await,
-        BountyCmd::List { repo, status, node } => cmd_list(repo, status, node).await,
-        BountyCmd::Show { id, node } => cmd_show(id, node).await,
+        BountyCmd::List {
+            repo,
+            status,
+            node,
+            dir,
+        } => cmd_list(repo, status, node, dir).await,
+        BountyCmd::Show { id, node, dir } => cmd_show(id, node, dir).await,
        BountyCmd::Claim {
            id,
            wallet,
@@ -192,8 +205,13 @@ async fn cmd_create(
    Ok(())
 }

-async fn cmd_list(repo: Option<String>, status: Option<String>, node: String) -> Result<()> {
-    let client = NodeClient::new(&node, None);
+async fn cmd_list(
+    repo: Option<String>,
+    status: Option<String>,
+    node: String,
+    dir: Option<PathBuf>,
+) -> Result<()> {
+    let client = signed_client(&node, dir.as_deref());

    let url = if let Some(ref repo) = repo {
        let (owner, name) = repo
@@ -214,7 +232,7 @@ async fn cmd_list(repo: Option<String>, status: Option<String>, node: String) ->
    };

    let resp = client
-        .get(&url)
+        .get_authed(&url)
        .await
        .context("failed to connect to node")?;
    let body: Value = resp.json().await.unwrap_or_default();
@@ -237,9 +255,9 @@ async fn cmd_list(repo: Option<String>, status: Option<String>, node: String) ->
    Ok(())
 }

-async fn cmd_show(id: String, node: String) -> Result<()> {
-    let client = NodeClient::new(&node, None);
-    let resp = client.get(&format!("/api/v1/bounties/{id}")).await?;
+async fn cmd_show(id: String, node: String, dir: Option<PathBuf>) -> Result<()> {
+    let client = signed_client(&node, dir.as_deref());
+    let resp = client.get_authed(&format!("/api/v1/bounties/{id}")).await?;

    let status = resp.status();
    let body: Value = resp.json().await.unwrap_or_default();
@@ -462,7 +480,7 @@ mod tests {
            .create_async()
            .await;

-        cmd_list(None, None, server.url()).await.unwrap();
+        cmd_list(None, None, server.url(), None).await.unwrap();
    }

    #[tokio::test]
@@ -506,7 +524,7 @@ mod tests {
            .create_async()
            .await;

-        let err = cmd_show("nonexistent".to_string(), server.url())
+        let err = cmd_show("nonexistent".to_string(), server.url(), None)
            .await
            .unwrap_err();
        assert!(err.to_string().contains("not found"));
@@ -5,10 +5,15 @@
 use anyhow::{Context, Result};
 use clap::{Args, Subcommand};
 use serde_json::Value;
+use std::path::PathBuf;

 use crate::http::NodeClient;
 use crate::identity::load_keypair_from_dir;

+fn signed_client(node: &str, dir: Option<&std::path::Path>) -> NodeClient {
+    NodeClient::new(node, load_keypair_from_dir(dir).ok())
+}
+
 #[derive(Args)]
 pub struct CertArgs {
    #[command(subcommand)]
@@ -23,6 +28,8 @@ pub enum CertCmd {
        repo: String,
        #[arg(long, default_value = "https://node.gitlawb.com", env = "GITLAWB_NODE")]
        node: String,
+        #[arg(long)]
+        dir: Option<PathBuf>,
    },
    /// Show a specific ref certificate and verify its signature
    Show {
@@ -32,28 +39,39 @@ pub enum CertCmd {
        id: String,
        #[arg(long, default_value = "https://node.gitlawb.com", env = "GITLAWB_NODE")]
        node: String,
+        #[arg(long)]
+        dir: Option<PathBuf>,
    },
 }

 pub async fn run(args: CertArgs) -> Result<()> {
    match args.cmd {
-        CertCmd::List { repo, node } => cmd_list(repo, node).await,
-        CertCmd::Show { repo, id, node } => cmd_show(repo, id, node).await,
+        CertCmd::List { repo, node, dir } => cmd_list(repo, node, dir).await,
+        CertCmd::Show {
+            repo,
+            id,
+            node,
+            dir,
+        } => cmd_show(repo, id, node, dir).await,
    }
 }

 /// Resolve "repo" into (owner, name) using the caller's DID when no slash is given.
-async fn resolve_repo(repo: &str, node: &str) -> Result<(String, String)> {
+async fn resolve_repo(
+    repo: &str,
+    node: &str,
+    dir: Option<&std::path::Path>,
+) -> Result<(String, String)> {
    if let Some((owner, name)) = repo.split_once('/') {
        Ok((owner.to_string(), name.to_string()))
    } else {
-        let short = if let Ok(kp) = load_keypair_from_dir(None) {
+        let short = if let Ok(kp) = load_keypair_from_dir(dir) {
            let did = kp.did().to_string();
            did.split(':').next_back().unwrap_or(&did).to_string()
        } else {
-            let client = NodeClient::new(node, None);
+            let client = signed_client(node, dir);
            let info: Value = client
-                .get("/")
+                .get_authed("/")
                .await?
                .json()
                .await
@@ -65,13 +83,13 @@ async fn resolve_repo(repo: &str, node: &str) -> Result<(String, String)> {
    }
 }

-async fn cmd_list(repo: String, node: String) -> Result<()> {
-    let (owner, name) = resolve_repo(&repo, &node).await?;
+async fn cmd_list(repo: String, node: String, dir: Option<PathBuf>) -> Result<()> {
+    let (owner, name) = resolve_repo(&repo, &node, dir.as_deref()).await?;

-    let client = NodeClient::new(&node, None);
+    let client = signed_client(&node, dir.as_deref());
    let path = format!("/api/v1/repos/{owner}/{name}/certs");
    let resp: Value = client
-        .get(&path)
+        .get_authed(&path)
        .await?
        .json()
        .await
@@ -96,16 +114,16 @@ async fn cmd_list(repo: String, node: String) -> Result<()> {
    Ok(())
 }

-async fn cmd_show(repo: String, id: String, node: String) -> Result<()> {
-    let (owner, name) = resolve_repo(&repo, &node).await?;
+async fn cmd_show(repo: String, id: String, node: String, dir: Option<PathBuf>) -> Result<()> {
+    let (owner, name) = resolve_repo(&repo, &node, dir.as_deref()).await?;

-    let client = NodeClient::new(&node, None);
+    let client = signed_client(&node, dir.as_deref());
    let id = resolve_cert_id(&client, &owner, &name, &id).await?;

    // Fetch the certificate
    let path = format!("/api/v1/repos/{owner}/{name}/certs/{id}");
    let resp = client
-        .get(&path)
+        .get_authed(&path)
        .await?
        .error_for_status()
        .context("certificate not found")?;
@@ -168,9 +186,9 @@ async fn resolve_cert_id(client: &NodeClient, owner: &str, name: &str, id: &str)
        return Ok(id.to_string());
    }

-    let path = format!("/api/v1/repos/{owner}/{name}/certs");
+    let path = format!("/api/v1/repos/{owner}/{name}/certs?prefix={id}");
    let resp: Value = client
-        .get(&path)
+        .get_authed(&path)
        .await?
        .error_for_status()
        .context("failed to list certificates")?
@@ -182,7 +200,6 @@ async fn resolve_cert_id(client: &NodeClient, owner: &str, name: &str, id: &str)
    let matches: Vec<String> = certs
        .iter()
        .filter_map(|cert| cert["id"].as_str())
-        .filter(|cert_id| cert_id.starts_with(id))
        .map(ToString::to_string)
        .collect();

@@ -45,6 +45,15 @@ impl NodeClient {
            .with_context(|| format!("GET {url}"))
    }

+    /// GET that signs when a keypair is available; falls back to unsigned for public repos.
+    pub async fn get_authed(&self, path: &str) -> Result<reqwest::Response> {
+        if self.keypair.is_some() {
+            self.get_signed(path).await
+        } else {
+            self.get(path).await
+        }
+    }
+
    /// GET with RFC 9421 HTTP Signature auth, for owner-only read endpoints.
    /// Signs over the empty body (same shape the node verifies for signed reads).
    pub async fn get_signed(&self, path: &str) -> Result<reqwest::Response> {
@@ -176,3 +185,389 @@ async fn obtain_proof(cfg: IcaptchaCfg) -> Result<String> {
        .await
        .context("iCaptcha solver task panicked")?
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use gitlawb_core::identity::Keypair;
+    use mockito::Server;
+    use std::ffi::OsString;
+    use std::sync::{Mutex, MutexGuard};
+
+    /// Serializes the two integration tests that touch the process-global
+    /// `GITLAWB_ICAPTCHA_URL` / `GITLAWB_ICAPTCHA_INSECURE` env vars so they
+    /// never race.
+    static ICAPTCHA_ENV_LOCK: Mutex<()> = Mutex::new(());
+
+    fn test_keypair() -> Keypair {
+        Keypair::generate()
+    }
+
+    fn headers_from_pairs(pairs: &[(&str, &str)]) -> reqwest::header::HeaderMap {
+        let mut h = reqwest::header::HeaderMap::new();
+        for (k, v) in pairs {
+            h.insert(
+                k.parse::<reqwest::header::HeaderName>().unwrap(),
+                v.parse::<reqwest::header::HeaderValue>().unwrap(),
+            );
+        }
+        h
+    }
+
+    // ── icaptcha_cfg ────────────────────────────────────────────────────
+
+    #[test]
+    fn icaptcha_cfg_returns_some_when_both_headers_present() {
+        let kp = test_keypair();
+        let client = NodeClient::new("http://localhost", Some(kp.clone()));
+        let headers = headers_from_pairs(&[
+            ("x-icaptcha-url", "https://icaptcha.gitlawb.com"),
+            ("x-icaptcha-level", "3"),
+        ]);
+        let cfg = client.icaptcha_cfg(&headers).unwrap().unwrap();
+        assert_eq!(cfg.did, kp.did().to_string());
+        assert_eq!(cfg.level, 3);
+    }
+
+    #[test]
+    fn icaptcha_cfg_defaults_level_when_only_url_present() {
+        let kp = test_keypair();
+        let client = NodeClient::new("http://localhost", Some(kp));
+        let headers = headers_from_pairs(&[("x-icaptcha-url", "https://icaptcha.gitlawb.com")]);
+        let cfg = client.icaptcha_cfg(&headers).unwrap().unwrap();
+        assert_eq!(cfg.level, icaptcha_client::DEFAULT_LEVEL);
+    }
+
+    #[test]
+    fn icaptcha_cfg_defaults_url_when_only_level_present() {
+        let kp = test_keypair();
+        let client = NodeClient::new("http://localhost", Some(kp));
+        let headers = headers_from_pairs(&[("x-icaptcha-level", "5")]);
+        let cfg = client.icaptcha_cfg(&headers).unwrap().unwrap();
+        assert_eq!(cfg.level, 5);
+    }
+
+    #[test]
+    fn icaptcha_cfg_returns_none_without_icaptcha_headers() {
+        let client = NodeClient::new("http://localhost", Some(test_keypair()));
+        let headers = reqwest::header::HeaderMap::new();
+        assert!(client.icaptcha_cfg(&headers).unwrap().is_none());
+    }
+
+    #[test]
+    fn icaptcha_cfg_returns_none_with_unrelated_headers() {
+        let client = NodeClient::new("http://localhost", Some(test_keypair()));
+        let headers = headers_from_pairs(&[("content-type", "application/json")]);
+        assert!(client.icaptcha_cfg(&headers).unwrap().is_none());
+    }
+
+    #[test]
+    fn icaptcha_cfg_errors_when_no_keypair() {
+        let client = NodeClient::new("http://localhost", None);
+        let headers = headers_from_pairs(&[("x-icaptcha-level", "3")]);
+        let err = client.icaptcha_cfg(&headers).unwrap_err();
+        assert!(err.to_string().contains("identity keypair"));
+    }
+
+    #[test]
+    fn icaptcha_cfg_ignores_unparseable_level() {
+        let client = NodeClient::new("http://localhost", Some(test_keypair()));
+        let headers = headers_from_pairs(&[
+            ("x-icaptcha-url", "https://icaptcha.gitlawb.com"),
+            ("x-icaptcha-level", "not-a-number"),
+        ]);
+        let cfg = client.icaptcha_cfg(&headers).unwrap().unwrap();
+        assert_eq!(cfg.level, icaptcha_client::DEFAULT_LEVEL);
+    }
+
+    // ── send_once ───────────────────────────────────────────────────────
+
+    #[tokio::test]
+    async fn send_once_attaches_proof_header_when_provided() {
+        let mut server = Server::new_async().await;
+        let m = server
+            .mock("POST", "/api/test")
+            .match_header("x-icaptcha-proof", "test.proof.token")
+            .with_status(200)
+            .with_body("ok")
+            .create_async()
+            .await;
+        let client = NodeClient::new(server.url(), None);
+        let resp = client
+            .send_once("POST", "/api/test", b"{}", Some("test.proof.token"))
+            .await
+            .unwrap();
+        assert_eq!(resp.status(), 200);
+        m.assert();
+    }
+
+    #[tokio::test]
+    async fn send_once_omits_proof_header_when_not_provided() {
+        let mut server = Server::new_async().await;
+        let m = server
+            .mock("POST", "/api/test")
+            .match_header("x-icaptcha-proof", mockito::Matcher::Missing)
+            .with_status(200)
+            .with_body("ok")
+            .create_async()
+            .await;
+        let client = NodeClient::new(server.url(), None);
+        let resp = client
+            .send_once("POST", "/api/test", b"{}", None)
+            .await
+            .unwrap();
+        assert_eq!(resp.status(), 200);
+        m.assert();
+    }
+
+    #[tokio::test]
+    async fn send_once_signs_request_when_keypair_present() {
+        let mut server = Server::new_async().await;
+        let m = server
+            .mock("POST", "/api/test")
+            .match_header("Signature", mockito::Matcher::Any)
+            .match_header("Signature-Input", mockito::Matcher::Any)
+            .match_header("Content-Digest", mockito::Matcher::Any)
+            .with_status(200)
+            .with_body("ok")
+            .create_async()
+            .await;
+        let client = NodeClient::new(server.url(), Some(test_keypair()));
+        let resp = client
+            .send_once("POST", "/api/test", b"{}", None)
+            .await
+            .unwrap();
+        assert_eq!(resp.status(), 200);
+        m.assert();
+    }
+
+    #[tokio::test]
+    async fn send_once_does_not_sign_when_no_keypair() {
+        let mut server = Server::new_async().await;
+        let m = server
+            .mock("POST", "/api/test")
+            .match_header("Signature", mockito::Matcher::Missing)
+            .match_header("Signature-Input", mockito::Matcher::Missing)
+            .match_header("Content-Digest", mockito::Matcher::Missing)
+            .with_status(200)
+            .with_body("ok")
+            .create_async()
+            .await;
+        let client = NodeClient::new(server.url(), None);
+        let resp = client
+            .send_once("POST", "/api/test", b"{}", None)
+            .await
+            .unwrap();
+        assert_eq!(resp.status(), 200);
+        m.assert();
+    }
+
+    // ── send_signed ─────────────────────────────────────────────────────
+
+    #[tokio::test]
+    async fn send_signed_returns_non_icaptcha_403_without_retry() {
+        let mut server = Server::new_async().await;
+        let m = server
+            .mock("POST", "/api/register")
+            .with_status(403)
+            .with_header("content-type", "application/json")
+            .with_body(r#"{"error":"forbidden"}"#)
+            .create_async()
+            .await;
+        let client = NodeClient::new(server.url(), Some(test_keypair()));
+        let resp = client
+            .send_signed("POST", "/api/register", b"{}")
+            .await
+            .unwrap();
+        assert_eq!(resp.status(), 403);
+        m.assert();
+    }
+
+    #[tokio::test]
+    async fn send_signed_returns_first_response_on_success() {
+        let mut server = Server::new_async().await;
+        let m = server
+            .mock("POST", "/api/register")
+            .with_status(201)
+            .with_header("content-type", "application/json")
+            .with_body(r#"{"status":"created"}"#)
+            .create_async()
+            .await;
+        let client = NodeClient::new(server.url(), Some(test_keypair()));
+        let resp = client
+            .send_signed("POST", "/api/register", b"{}")
+            .await
+            .unwrap();
+        assert_eq!(resp.status(), 201);
+        m.assert();
+    }
+
+    #[tokio::test]
+    async fn send_signed_handles_405_not_icaptcha() {
+        let mut server = Server::new_async().await;
+        let m = server
+            .mock("POST", "/api/register")
+            .with_status(405)
+            .with_body(r#"{"error":"method not allowed"}"#)
+            .create_async()
+            .await;
+        let client = NodeClient::new(server.url(), Some(test_keypair()));
+        let resp = client
+            .send_signed("POST", "/api/register", b"{}")
+            .await
+            .unwrap();
+        assert_eq!(resp.status(), 405);
+        m.assert();
+    }
+
+    // ── send_signed iCaptcha retry (full integration) ────────────────────
+
+    /// Set GITLAWB_ICAPTCHA_URL and GITLAWB_ICAPTCHA_INSECURE so the iCaptcha
+    /// client trusts a local mockito HTTP server, restoring any prior values on
+    /// drop so a test run launched with those variables keeps working.
+    /// Holds [`ICAPTCHA_ENV_LOCK`] for its lifetime so concurrent tests don't
+    /// race on the process-global env vars.
+    struct IcaptchaEnv {
+        _lock: MutexGuard<'static, ()>,
+        prev_url: Option<OsString>,
+        prev_insecure: Option<OsString>,
+    }
+
+    impl IcaptchaEnv {
+        fn new(url: &str) -> Self {
+            let lock = ICAPTCHA_ENV_LOCK.lock().unwrap();
+            let prev_url = std::env::var_os("GITLAWB_ICAPTCHA_URL");
+            let prev_insecure = std::env::var_os("GITLAWB_ICAPTCHA_INSECURE");
+            std::env::set_var("GITLAWB_ICAPTCHA_URL", url);
+            std::env::set_var("GITLAWB_ICAPTCHA_INSECURE", "1");
+            IcaptchaEnv {
+                _lock: lock,
+                prev_url,
+                prev_insecure,
+            }
+        }
+    }
+
+    impl Drop for IcaptchaEnv {
+        fn drop(&mut self) {
+            match self.prev_url.take() {
+                Some(v) => std::env::set_var("GITLAWB_ICAPTCHA_URL", v),
+                None => std::env::remove_var("GITLAWB_ICAPTCHA_URL"),
+            }
+            match self.prev_insecure.take() {
+                Some(v) => std::env::set_var("GITLAWB_ICAPTCHA_INSECURE", v),
+                None => std::env::remove_var("GITLAWB_ICAPTCHA_INSECURE"),
+            }
+        }
+    }
+
+    /// Set up a mock iCaptcha server that responds to challenge + answer.
+    /// `hits` sets the expected call count for both endpoints so the test can
+    /// verify the solve loop was entered the correct number of times.
+    struct MockIcaptcha {
+        challenge: mockito::Mock,
+        answer: mockito::Mock,
+        _guard: IcaptchaEnv,
+        url: String,
+    }
+
+    impl MockIcaptcha {
+        async fn new(server: &mut mockito::ServerGuard, hits: usize) -> Self {
+            let url = server.url();
+            let guard = IcaptchaEnv::new(&url);
+            let challenge = server
+                .mock("POST", "/v1/challenge")
+                .with_status(200)
+                .with_header("content-type", "application/json")
+                .with_body(
+                    r#"{"challengeId":"c1","type":"arithmetic","difficulty":1,"prompt":"What is 1 + 1?","token":"tk1"}"#,
+                )
+                .expect(hits)
+                .create_async()
+                .await;
+            let answer = server
+                .mock("POST", "/v1/answer")
+                .with_status(200)
+                .with_header("content-type", "application/json")
+                .with_body(r#"{"status":"passed","proof":"mock.proof"}"#)
+                .expect(hits)
+                .create_async()
+                .await;
+            Self {
+                challenge,
+                answer,
+                _guard: guard,
+                url,
+            }
+        }
+    }
+
+    #[tokio::test]
+    async fn send_signed_solves_icaptcha_and_retries_to_success() {
+        let mut node = Server::new_async().await;
+        let mut icaptcha = Server::new_async().await;
+        let ic = MockIcaptcha::new(&mut icaptcha, 1).await;
+
+        let n1 = node
+            .mock("POST", "/api/register")
+            .with_status(403)
+            .with_header("content-type", "application/json")
+            .with_header("x-icaptcha-url", &ic.url)
+            .with_header("x-icaptcha-level", "3")
+            .with_body(r#"{"error":"icaptcha_proof_required"}"#)
+            .expect(1)
+            .create_async()
+            .await;
+        let n2 = node
+            .mock("POST", "/api/register")
+            .match_header("x-icaptcha-proof", "mock.proof")
+            .with_status(201)
+            .with_header("content-type", "application/json")
+            .with_body(r#"{"status":"created"}"#)
+            .expect(1)
+            .create_async()
+            .await;
+
+        let client = NodeClient::new(node.url(), Some(test_keypair()));
+        let resp = client
+            .send_signed("POST", "/api/register", b"{}")
+            .await
+            .unwrap();
+        assert_eq!(resp.status(), 201);
+        n1.assert();
+        n2.assert();
+        ic.challenge.assert();
+        ic.answer.assert();
+    }
+
+    #[tokio::test]
+    async fn send_signed_returns_403_after_icaptcha_retries_exhausted() {
+        let mut node = Server::new_async().await;
+        let mut icaptcha = Server::new_async().await;
+        // MAX_ICAPTCHA_RETRIES = 2, so with every call returning 403 with
+        // iCaptcha headers the solve loop runs twice (2 challenge + 2 answer).
+        let ic = MockIcaptcha::new(&mut icaptcha, 2).await;
+
+        // The original + 2 retries = 3 node calls before the loop gives up.
+        let n = node
+            .mock("POST", "/api/register")
+            .with_status(403)
+            .with_header("content-type", "application/json")
+            .with_header("x-icaptcha-url", &ic.url)
+            .with_header("x-icaptcha-level", "3")
+            .with_body(r#"{"error":"icaptcha_proof_required"}"#)
+            .expect(3)
+            .create_async()
+            .await;
+
+        let client = NodeClient::new(node.url(), Some(test_keypair()));
+        let resp = client
+            .send_signed("POST", "/api/register", b"{}")
+            .await
+            .unwrap();
+        assert_eq!(resp.status(), 403);
+        n.assert();
+        ic.challenge.assert();
+        ic.answer.assert();
+    }
+}
@@ -33,13 +33,16 @@ pub enum IpfsCmd {
        cid: String,
        #[arg(long, default_value = "https://node.gitlawb.com", env = "GITLAWB_NODE")]
        node: String,
+        /// Identity directory (default: ~/.gitlawb)
+        #[arg(long)]
+        dir: Option<PathBuf>,
    },
 }

 pub async fn run(args: IpfsArgs) -> Result<()> {
    match args.cmd {
        IpfsCmd::List { node, dir } => cmd_list(node, dir).await,
-        IpfsCmd::Get { cid, node } => cmd_get(cid, node).await,
+        IpfsCmd::Get { cid, node, dir } => cmd_get(cid, node, dir).await,
    }
 }

@@ -86,11 +89,32 @@ async fn cmd_list(node: String, dir: Option<PathBuf>) -> Result<()> {
    Ok(())
 }

-async fn cmd_get(cid: String, node: String) -> Result<()> {
-    let client = NodeClient::new(&node, None);
-    let path = format!("/ipfs/{cid}");
+async fn cmd_get(cid: String, node: String, dir: Option<PathBuf>) -> Result<()> {
+    // #173 (F5): the resolver now serves path-scoped objects to authorized readers,
+    // so sign with an available identity like `gl ipfs list` — otherwise an owner or
+    // listed reader gets the opaque anonymous 404 for content they can read.
+    // `get_authed` signs when a keypair is present and falls back to unsigned.
+    //
+    // An explicit `--dir` is a request to use THAT identity: propagate a
+    // missing/corrupt-keystore error (like `list`) instead of silently sending an
+    // anonymous request the authorized reader would see as the node's opaque 404
+    // (#173 review). Only the default (no `--dir`) keeps the best-effort unsigned
+    // fallback, so `get` stays usable for genuinely public content.
+    let keypair = match dir.as_deref() {
+        Some(dir) => Some(crate::identity::load_keypair_from_dir(Some(dir))?),
+        None => crate::identity::load_keypair_from_dir(None).ok(),
+    };
+    let client = NodeClient::new(&node, keypair);
+    // #173 review (F1): the node now accepts equivalent multibase spellings,
+    // including base64 CIDs (prefix 'm'), whose alphabet contains '/', '+', '='.
+    // Interpolating the CID raw would make the client request (and sign)
+    // `/ipfs/<prefix>/<suffix>`, which neither matches the single-segment Axum
+    // route nor points at the intended target. Percent-encode the CID as exactly
+    // one path segment so the signed and sent target agree and the server's
+    // `Path` extractor decodes it back to the original CID.
+    let path = format!("/ipfs/{}", encode_cid_segment(&cid));
    let resp = client
-        .get(&path)
+        .get_authed(&path)
        .await
        .with_context(|| format!("failed to fetch CID {cid} from {node}"))?;

@@ -119,6 +143,16 @@ async fn cmd_get(cid: String, node: String) -> Result<()> {
    Ok(())
 }

+/// Percent-encode a CID so it occupies exactly one path segment of `/ipfs/<cid>`.
+/// `urlencoding::encode` escapes every byte outside the RFC 3986 unreserved set
+/// (ALPHA / DIGIT / `-._~`), so the base64-CID characters that would otherwise
+/// break the single-segment route — `/`, `+`, `=` — are all escaped, and the
+/// server's `Path` extractor decodes the result back to the original CID (#173
+/// review, F1).
+fn encode_cid_segment(cid: &str) -> String {
+    urlencoding::encode(cid).into_owned()
+}
+
 #[cfg(test)]
 mod tests {
    use super::*;
@@ -235,4 +269,162 @@ mod tests {

        m.assert_async().await;
    }
+
+    /// #173 (F5): `gl ipfs get` must SIGN with an available identity, like
+    /// `gl ipfs list`, so an owner/reader can retrieve a path-scoped object the node
+    /// now resolves by CID. RED before the fix: cmd_get ignores the identity dir and
+    /// sends an unsigned request, so the signature-matching mock is never hit
+    /// (cmd_get errors on the unmatched 501, and m.assert fails). GREEN after: the
+    /// signed request carries the RFC 9421 headers and is served 200.
+    #[tokio::test]
+    async fn test_cmd_get_signs_when_identity_present() {
+        let mut server = mockito::Server::new_async().await;
+        let keystore = seed_keystore();
+
+        let m = server
+            .mock("GET", "/ipfs/bafkreitestcid")
+            .match_header("signature", mockito::Matcher::Any)
+            .match_header("signature-input", mockito::Matcher::Any)
+            .with_status(200)
+            .with_header("content-type", "application/octet-stream")
+            .with_header("x-git-hash", "abc123")
+            .with_body("object bytes")
+            .create_async()
+            .await;
+
+        cmd_get(
+            "bafkreitestcid".to_string(),
+            server.url(),
+            Some(keystore.path().to_path_buf()),
+        )
+        .await
+        .expect("signed get of a resolvable object should succeed");
+
+        m.assert_async().await;
+    }
+
+    /// #173 (F5) must-not: a genuine anonymous denial must surface as an error, not
+    /// be masked as success. With no identity dir the request is unsigned; a 404
+    /// from the node must produce an Err mentioning the status.
+    #[tokio::test]
+    async fn test_cmd_get_anonymous_denial_is_error() {
+        let mut server = mockito::Server::new_async().await;
+
+        let m = server
+            .mock("GET", "/ipfs/bafkreidenied")
+            .with_status(404)
+            .with_header("content-type", "text/plain")
+            .with_body("no git object found")
+            .create_async()
+            .await;
+
+        let err = cmd_get("bafkreidenied".to_string(), server.url(), None)
+            .await
+            .expect_err("a 404 denial must be an error, not masked success");
+        assert!(
+            err.to_string().contains("404"),
+            "error should mention the status, got: {err}"
+        );
+
+        m.assert_async().await;
+    }
+
+    /// #173 (INV-8) must-not: the node's new 503 "search incomplete" (the legacy CID
+    /// scan hit its bound and could not prove absence) must surface as an actionable
+    /// Err naming the status, NOT be rendered as an empty/"not found" success — a
+    /// retryable outcome the caller has to see. Mirrors the 404 denial case for the
+    /// bounded-search response the resolver now emits.
+    #[tokio::test]
+    async fn test_cmd_get_search_incomplete_503_is_error() {
+        let mut server = mockito::Server::new_async().await;
+
+        let m = server
+            .mock("GET", "/ipfs/bafkreiincomplete")
+            .with_status(503)
+            .with_header("content-type", "application/json")
+            .with_body(r#"{"error":"search_incomplete","message":"CID search incomplete — retry"}"#)
+            .create_async()
+            .await;
+
+        let err = cmd_get("bafkreiincomplete".to_string(), server.url(), None)
+            .await
+            .expect_err("a 503 incomplete-search must be an error, not masked as not-found");
+        assert!(
+            err.to_string().contains("503"),
+            "error should mention the status, got: {err}"
+        );
+
+        m.assert_async().await;
+    }
+
+    /// #173 review (F1): a base64 CID (multibase prefix 'm') can contain '/', '+',
+    /// and '='. The client must percent-encode it into ONE path segment before
+    /// building and signing `/ipfs/<cid>`; otherwise the '/' splits the target so
+    /// it misses the single-segment Axum route and the signature covers the wrong
+    /// path. Assert the encoded segment carries no raw '/', '+', or '=', and that
+    /// it decodes back to the original CID (the server's `Path` extractor performs
+    /// that same decode). RED with the old raw `format!("/ipfs/{cid}")`: the
+    /// segment still contains '/'.
+    #[test]
+    fn test_encode_cid_segment_escapes_base64_alphabet() {
+        let cid = "mFoo/Bar+baz==";
+        let encoded = encode_cid_segment(cid);
+
+        assert!(
+            !encoded.contains('/'),
+            "encoded CID must be a single path segment (no raw '/'), got: {encoded}"
+        );
+        assert!(
+            !encoded.contains('+'),
+            "encoded CID must escape '+', got: {encoded}"
+        );
+        assert!(
+            !encoded.contains('='),
+            "encoded CID must escape '=', got: {encoded}"
+        );
+
+        let decoded = urlencoding::decode(&encoded).expect("encoded CID must decode");
+        assert_eq!(
+            decoded, cid,
+            "encoding must round-trip back to the original CID"
+        );
+    }
+
+    /// #173 review: `gl ipfs get --dir <path>` must PROPAGATE a missing/corrupt
+    /// identity-load error like `gl ipfs list`, not silently fall back to an anonymous
+    /// request — otherwise an authorized reader pointing `--dir` at a broken keystore
+    /// gets the node's opaque 404 instead of the actionable key-load error. The
+    /// unsigned fallback is preserved only when NO `--dir` is given (covered by
+    /// `test_cmd_get_anonymous_denial_is_error`). RED before the fix (`.ok()` swallows
+    /// the error, an anonymous request is sent, and the `.expect(0)` mock is hit),
+    /// GREEN after.
+    #[tokio::test]
+    async fn test_cmd_get_explicit_dir_no_identity_errors_without_request() {
+        let mut server = mockito::Server::new_async().await;
+        // Empty keystore dir passed explicitly via --dir: no identity.pem present.
+        let empty = tempfile::TempDir::new().unwrap();
+
+        // The endpoint must never be hit when an explicit --dir fails to load.
+        let m = server
+            .mock("GET", "/ipfs/bafkreitestcid")
+            .expect(0)
+            .create_async()
+            .await;
+
+        let err = cmd_get(
+            "bafkreitestcid".to_string(),
+            server.url(),
+            Some(empty.path().to_path_buf()),
+        )
+        .await
+        .expect_err("an explicit --dir that fails to load must be an error");
+        assert!(
+            err.to_string().contains("gl identity new")
+                || err.to_string().contains("no identity found")
+                || err.to_string().contains("failed to load keypair"),
+            "error should name the key-load failure, got: {err}"
+        );
+
+        m.assert_async().await;
+    }
 }
@@ -10,6 +10,10 @@ use uuid::Uuid;
 use crate::http::NodeClient;
 use crate::identity::load_keypair_from_dir;

+fn signed_client(node: &str, dir: Option<&std::path::Path>) -> NodeClient {
+    NodeClient::new(node, load_keypair_from_dir(dir).ok())
+}
+
 #[derive(Args)]
 pub struct IssueArgs {
    #[command(subcommand)]
@@ -215,10 +219,10 @@ async fn cmd_create(
 async fn cmd_list(repo: String, node: String, dir: Option<PathBuf>) -> Result<()> {
    let (owner, name) = resolve_repo(&repo, &node, dir.as_deref()).await?;

-    let client = NodeClient::new(&node, None);
+    let client = signed_client(&node, dir.as_deref());
    let path = format!("/api/v1/repos/{owner}/{name}/issues");
    let resp: Value = client
-        .get(&path)
+        .get_authed(&path)
        .await?
        .json()
        .await
@@ -254,10 +258,10 @@ async fn cmd_list(repo: String, node: String, dir: Option<PathBuf>) -> Result<()
 async fn cmd_show(repo: String, id: String, node: String, dir: Option<PathBuf>) -> Result<()> {
    let (owner, name) = resolve_repo(&repo, &node, dir.as_deref()).await?;

-    let client = NodeClient::new(&node, None);
+    let client = signed_client(&node, dir.as_deref());
    let path = format!("/api/v1/repos/{owner}/{name}/issues/{id}");
    let resp = client
-        .get(&path)
+        .get_authed(&path)
        .await
        .context("failed to connect to node")?;
    let status = resp.status();
@@ -347,10 +351,10 @@ async fn cmd_issue_comments(
    dir: Option<PathBuf>,
 ) -> Result<()> {
    let (owner, name) = resolve_repo(&repo, &node, dir.as_deref()).await?;
-    let client = NodeClient::new(&node, None);
+    let client = signed_client(&node, dir.as_deref());

    let resp: Value = client
-        .get(&format!(
+        .get_authed(&format!(
            "/api/v1/repos/{owner}/{name}/issues/{id}/comments"
        ))
        .await?
@@ -970,14 +970,14 @@ async fn call_tool(
                }
                u
            };
-            let resp: Value = client.get(&url).await?.json().await?;
+            let resp: Value = client.get_authed(&url).await?.json().await?;
            Ok(serde_json::to_string_pretty(&resp)?)
        }

        "bounty_show" => {
            let id = args["id"].as_str().context("missing 'id'")?;
            let resp: Value = client
-                .get(&format!("/api/v1/bounties/{id}"))
+                .get_authed(&format!("/api/v1/bounties/{id}"))
                .await?
                .json()
                .await?;
@@ -1165,7 +1165,7 @@ async fn call_tool(
                (owner, repo.to_string())
            };
            let resp: Value = client
-                .get(&format!("/api/v1/repos/{owner}/{name}/issues"))
+                .get_authed(&format!("/api/v1/repos/{owner}/{name}/issues"))
                .await?
                .json()
                .await?;
@@ -658,10 +658,10 @@ async fn cmd_label_remove(

 async fn cmd_label_list(repo: String, node: String, dir: Option<PathBuf>) -> Result<()> {
    let (owner, name) = resolve_owner_repo_pair(&repo, &node, dir.as_deref()).await?;
-    let client = NodeClient::new(&node, None);
+    let client = NodeClient::new(&node, load_keypair_from_dir(dir.as_deref()).ok());

    let resp: Value = client
-        .get(&format!("/api/v1/repos/{owner}/{name}/labels"))
+        .get_authed(&format!("/api/v1/repos/{owner}/{name}/labels"))
        .await?
        .json()
        .await
@@ -34,12 +34,14 @@ pub enum StarCmd {
        #[arg(long)]
        dir: Option<PathBuf>,
    },
-    /// Show star count for a repository (no auth required)
+    /// Show star count for a repository
    Count {
        /// Repository in owner/repo format
        repo: String,
        #[arg(long, default_value = "https://node.gitlawb.com", env = "GITLAWB_NODE")]
        node: String,
+        #[arg(long)]
+        dir: Option<PathBuf>,
    },
 }

@@ -47,7 +49,7 @@ pub async fn run(args: StarArgs) -> Result<()> {
    match args.cmd {
        StarCmd::Add { repo, node, dir } => cmd_add(repo, node, dir).await,
        StarCmd::Remove { repo, node, dir } => cmd_remove(repo, node, dir).await,
-        StarCmd::Count { repo, node } => cmd_count(repo, node).await,
+        StarCmd::Count { repo, node, dir } => cmd_count(repo, node, dir).await,
    }
 }

@@ -110,15 +112,15 @@ async fn cmd_remove(repo: String, node: String, dir: Option<PathBuf>) -> Result<
    Ok(())
 }

-async fn cmd_count(repo: String, node: String) -> Result<()> {
+async fn cmd_count(repo: String, node: String, dir: Option<PathBuf>) -> Result<()> {
    let (owner, name) = repo
        .split_once('/')
        .map(|(o, n)| (o.to_string(), n.to_string()))
        .context("use owner/repo format for count (e.g. alice/myrepo)")?;
-    let client = NodeClient::new(&node, None);
+    let client = NodeClient::new(&node, load_keypair_from_dir(dir.as_deref()).ok());

    let resp = client
-        .get(&format!("/api/v1/repos/{owner}/{name}/star"))
+        .get_authed(&format!("/api/v1/repos/{owner}/{name}/star"))
        .await
        .context("failed to connect to node")?;

@@ -310,16 +312,20 @@ mod tests {
            .create_async()
            .await;

-        cmd_count("alice/myrepo".to_string(), server.url())
+        cmd_count("alice/myrepo".to_string(), server.url(), None)
            .await
            .unwrap();
    }

    #[tokio::test]
    async fn test_cmd_count_requires_slash() {
-        let err = cmd_count("noslash".to_string(), "http://127.0.0.1:1".to_string())
-            .await
-            .unwrap_err();
+        let err = cmd_count(
+            "noslash".to_string(),
+            "http://127.0.0.1:1".to_string(),
+            None,
+        )
+        .await
+        .unwrap_err();
        assert!(err.to_string().contains("owner/repo format"));
    }

@@ -1,4 +1,4 @@
-use anyhow::Result;
+use anyhow::{Context, Result};
 use clap::{Args, Subcommand};
 use std::path::PathBuf;

@@ -30,15 +30,39 @@ pub enum SyncCmd {
 pub async fn run(args: SyncArgs) -> Result<()> {
    match args.cmd {
        SyncCmd::Trigger => {
-            let keypair = load_keypair_from_dir(args.dir.as_deref()).ok();
-            let client = NodeClient::new(&args.node, keypair);
-            let resp: serde_json::Value = client
-                .post("/api/v1/sync/trigger", b"{}")
-                .await?
-                .json()
-                .await?;
-            let peers = resp["peers_reached"].as_u64().unwrap_or(0);
-            let enqueued = resp["repos_enqueued"].as_u64().unwrap_or(0);
+            // /api/v1/sync/trigger always requires a signature, so a missing or
+            // unreadable identity must fail here, locally, rather than sending an
+            // unsigned request that can only 401 remotely (matches the other
+            // signed CLI writes).
+            let keypair = load_keypair_from_dir(args.dir.as_deref())
+                .context("identity not found — run `gl identity new` first")?;
+            let client = NodeClient::new(&args.node, Some(keypair));
+            let resp = client.post("/api/v1/sync/trigger", b"{}").await?;
+            // The node now requires a signature on this route and rate-limits it,
+            // so a denial (401/429/…) is expected. Check the status BEFORE parsing:
+            // otherwise a JSON-ish error body deserializes into a zero-count struct
+            // and prints a fabricated "✓ sync triggered / 0 peers" success.
+            let status = resp.status();
+            if !status.is_success() {
+                // Bound the read: a hostile or broken node must not force an
+                // unbounded allocation just to surface a denial (INV-6, read half).
+                let raw = read_body_capped(resp, 8 * 1024).await;
+                let msg = serde_json::from_str::<serde_json::Value>(&raw)
+                    .ok()
+                    .and_then(|v| {
+                        v.get("message")
+                            .or_else(|| v.get("error"))
+                            .and_then(|m| m.as_str())
+                            .map(str::to_string)
+                    })
+                    .unwrap_or(raw);
+                anyhow::bail!(
+                    "sync trigger failed ({status}): {}",
+                    sanitize_node_msg(&msg)
+                );
+            }
+            let resp: serde_json::Value = resp.json().await?;
+            let (peers, enqueued) = trigger_counts(&resp);
            println!("✓ sync triggered");
            println!("  peers reached:   {peers}");
            println!("  repos enqueued:  {enqueued}");
@@ -69,3 +93,254 @@ pub async fn run(args: SyncArgs) -> Result<()> {
    }
    Ok(())
 }
+
+/// Extract `(peers_reached, repos_enqueued)` from a successful sync-trigger
+/// response. Split out so the extraction is unit-testable (missing or malformed
+/// fields default to 0 rather than panicking).
+fn trigger_counts(resp: &serde_json::Value) -> (u64, u64) {
+    (
+        resp["peers_reached"].as_u64().unwrap_or(0),
+        resp["repos_enqueued"].as_u64().unwrap_or(0),
+    )
+}
+
+/// Read at most `cap` bytes of a response body. Bounds the allocation from a
+/// hostile or broken node returning a huge error body — the display is capped
+/// separately, but the read itself must not be unbounded (INV-6, read half).
+async fn read_body_capped(mut resp: reqwest::Response, cap: usize) -> String {
+    let mut buf: Vec<u8> = Vec::new();
+    while buf.len() < cap {
+        match resp.chunk().await {
+            Ok(Some(chunk)) => {
+                let take = (cap - buf.len()).min(chunk.len());
+                buf.extend_from_slice(&chunk[..take]);
+                if take < chunk.len() {
+                    break; // hit the cap mid-chunk
+                }
+            }
+            _ => break, // end of body or read error — return what we have
+        }
+    }
+    String::from_utf8_lossy(&buf).into_owned()
+}
+
+/// Strip terminal-dangerous characters from (and cap the length of) a
+/// node-supplied error string before surfacing it. The node a caller talks to
+/// could be hostile and embed escape sequences in its error body; those must not
+/// reach the terminal verbatim (INV-6). We drop the C0/C1 control bytes (which
+/// defangs ANSI/OSC escapes) AND the Unicode bidi/format controls (which
+/// `char::is_control` does not cover — they can reorder the displayed line).
+fn sanitize_node_msg(s: &str) -> String {
+    s.chars()
+        .filter(|c| !c.is_control() && !is_bidi_format(*c))
+        .take(200)
+        .collect()
+}
+
+/// Unicode bidirectional and directional-isolate format characters (category
+/// `Cf`). These are not `char::is_control()` (that is category `Cc` only), but a
+/// right-to-left override or isolate can visually reorder a terminal line to
+/// spoof the error text, so they are stripped alongside the control bytes.
+fn is_bidi_format(c: char) -> bool {
+    matches!(c,
+        '\u{200E}' | '\u{200F}' | '\u{061C}'   // LRM, RLM, ALM
+        | '\u{202A}'..='\u{202E}'              // LRE, RLE, PDF, LRO, RLO
+        | '\u{2066}'..='\u{2069}'              // LRI, RLI, FSI, PDI
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn trigger_args(node: String) -> (SyncArgs, tempfile::TempDir) {
+        // Seed a real identity so `run` gets past the mandatory-keypair check and
+        // reaches the status-handling path. The mocks below return a fixed status
+        // regardless of the signature, so these tests exercise the client's
+        // status-check-before-parse, not signature verification (that is proved
+        // server-side). Return the TempDir so the caller keeps it alive.
+        let dir = tempfile::TempDir::new().unwrap();
+        let kp = gitlawb_core::identity::Keypair::generate();
+        std::fs::write(
+            dir.path().join("identity.pem"),
+            kp.to_pem().unwrap().as_bytes(),
+        )
+        .unwrap();
+        let args = SyncArgs {
+            cmd: SyncCmd::Trigger,
+            node,
+            dir: Some(dir.path().to_path_buf()),
+        };
+        (args, dir)
+    }
+
+    #[tokio::test]
+    async fn trigger_requires_identity_fails_before_request() {
+        // Empty identity dir → no keypair. `sync trigger` must fail locally with
+        // a clear identity error BEFORE issuing any request. The node URL points
+        // at an unreachable port, so a request attempt would surface a different
+        // (connection) error; getting the identity error proves we never dialed.
+        let dir = tempfile::TempDir::new().unwrap();
+        let args = SyncArgs {
+            cmd: SyncCmd::Trigger,
+            node: "http://127.0.0.1:1".to_string(),
+            dir: Some(dir.path().to_path_buf()),
+        };
+        let err = run(args).await.unwrap_err();
+        assert!(
+            err.to_string().contains("identity not found"),
+            "expected a local identity error before any request, got: {err}"
+        );
+    }
+
+    #[tokio::test]
+    async fn trigger_surfaces_401_as_error_not_fake_success() {
+        let mut server = mockito::Server::new_async().await;
+        let _m = server
+            .mock("POST", "/api/v1/sync/trigger")
+            .with_status(401)
+            .with_header("content-type", "application/json")
+            // Valid JSON: the parse-without-status-check bug deserializes this
+            // into a zero-count success struct and prints "✓ sync triggered".
+            .with_body(r#"{"message":"unauthorized"}"#)
+            .create_async()
+            .await;
+        let (args, _dir) = trigger_args(server.url());
+        let err = run(args).await.unwrap_err();
+        assert!(
+            err.to_string().contains("401"),
+            "expected 401 surfaced, got: {err}"
+        );
+    }
+
+    #[tokio::test]
+    async fn trigger_surfaces_429_as_error() {
+        let mut server = mockito::Server::new_async().await;
+        let _m = server
+            .mock("POST", "/api/v1/sync/trigger")
+            .with_status(429)
+            .with_header("content-type", "application/json")
+            .with_body(r#"{"message":"slow down"}"#)
+            .create_async()
+            .await;
+        let (args, _dir) = trigger_args(server.url());
+        let err = run(args).await.unwrap_err();
+        assert!(
+            err.to_string().contains("429"),
+            "expected 429 surfaced, got: {err}"
+        );
+    }
+
+    #[tokio::test]
+    async fn trigger_sanitizes_control_chars_in_node_error() {
+        // A hostile node embeds an ANSI color escape (ESC) and a bell (BEL) in
+        // the JSON message field. The surfaced error must contain neither raw
+        // control byte, while keeping the printable text.
+        let mut server = mockito::Server::new_async().await;
+        let _m = server
+            .mock("POST", "/api/v1/sync/trigger")
+            .with_status(401)
+            .with_header("content-type", "application/json")
+            // Valid JSON whose message carries JSON-escaped ESC (\u001b) and
+            // BEL (\u0007); serde decodes them to real control bytes a naive
+            // client would print. (The status-check bug fake-successes here.)
+            .with_body("{\"message\":\"pwned\\u001b[31m\\u0007bad\"}")
+            .create_async()
+            .await;
+        let (args, _dir) = trigger_args(server.url());
+        let err = run(args).await.unwrap_err();
+        let s = err.to_string();
+        assert!(!s.contains('\u{1b}'), "ESC leaked to terminal: {s:?}");
+        assert!(!s.contains('\u{07}'), "BEL leaked to terminal: {s:?}");
+        assert!(
+            s.contains("pwned") && s.contains("bad"),
+            "message text dropped: {s:?}"
+        );
+    }
+
+    #[tokio::test]
+    async fn trigger_ok_prints_counts() {
+        let mut server = mockito::Server::new_async().await;
+        let _m = server
+            .mock("POST", "/api/v1/sync/trigger")
+            .with_status(200)
+            .with_header("content-type", "application/json")
+            .with_body(r#"{"peers_reached":2,"repos_enqueued":5}"#)
+            .create_async()
+            .await;
+        let (args, _dir) = trigger_args(server.url());
+        run(args).await.unwrap();
+    }
+
+    #[test]
+    fn sanitize_strips_controls_bidi_and_caps_length() {
+        // C0 (ESC/BEL) and the Cf bidi override (U+202E) are both removed; the
+        // printable text survives. (Note: a stripped ESC leaves any following
+        // "[31m" as inert literal text — that is the point, so the input here
+        // avoids that residue to keep the expectation unambiguous.)
+        let out = sanitize_node_msg("a\u{1b}\u{07}b\u{202e}c");
+        assert!(
+            !out.chars().any(|c| c.is_control()),
+            "control char leaked: {out:?}"
+        );
+        assert!(
+            !out.contains('\u{202e}'),
+            "RLO bidi override leaked: {out:?}"
+        );
+        assert_eq!(out, "abc");
+        // Length is capped at 200 chars regardless of input size.
+        let long = "x".repeat(250);
+        assert_eq!(sanitize_node_msg(&long).chars().count(), 200);
+    }
+
+    #[tokio::test]
+    async fn trigger_handles_oversized_error_body_without_unbounded_output() {
+        // A hostile/broken node returns a 2 MB error body. The command must still
+        // surface the denial with a bounded message, not hang or dump the body.
+        let mut server = mockito::Server::new_async().await;
+        let _m = server
+            .mock("POST", "/api/v1/sync/trigger")
+            .with_status(401)
+            .with_body("A".repeat(2_000_000))
+            .create_async()
+            .await;
+        let (args, _dir) = trigger_args(server.url());
+        let err = run(args).await.unwrap_err();
+        let s = err.to_string();
+        assert!(s.contains("401"), "denial not surfaced: {s:.80?}");
+        assert!(
+            s.len() < 500,
+            "error message not bounded: {} chars",
+            s.len()
+        );
+    }
+
+    #[tokio::test]
+    async fn read_body_capped_bounds_the_read() {
+        // The read must stop at the cap — a 2 MB body yields at most `cap` bytes,
+        // not the whole thing (which resp.text() would return).
+        let mut server = mockito::Server::new_async().await;
+        let _m = server
+            .mock("GET", "/big")
+            .with_status(200)
+            .with_body("A".repeat(2_000_000))
+            .create_async()
+            .await;
+        let resp = reqwest::get(format!("{}/big", server.url())).await.unwrap();
+        let out = read_body_capped(resp, 8192).await;
+        assert!(out.len() <= 8192, "read not bounded: {} bytes", out.len());
+        assert!(!out.is_empty(), "expected some body");
+    }
+
+    #[test]
+    fn trigger_counts_extracts_both_values() {
+        let v = serde_json::json!({"peers_reached": 2, "repos_enqueued": 5});
+        assert_eq!(trigger_counts(&v), (2, 5));
+        // Missing/malformed fields default to 0, never panic.
+        assert_eq!(trigger_counts(&serde_json::json!({})), (0, 0));
+        assert_eq!(
+            trigger_counts(&serde_json::json!({"peers_reached": "x"})),
+            (0, 0)
+        );
+    }
+}
@@ -15,3 +15,4 @@ serde_json = { workspace = true }
 anyhow = { workspace = true }
 thiserror = { workspace = true }
 tracing = { workspace = true }
+sha2 = { workspace = true }
@@ -19,6 +19,7 @@ use anyhow::{anyhow, bail, Context, Result};
 use serde::Deserialize;
 use serde_json::json;

+pub mod pow;
 pub mod solvers;

 /// Default iCaptcha service base URL (used when the node doesn't advertise one).
@@ -81,18 +82,42 @@ fn sanitize_excerpt(s: &str) -> String {
    out
 }

-/// Whether `u` parses as an `https` URL.
+/// Whether `u` parses as a trusted URL.
+///
+/// Production trusts only `https`.  When `GITLAWB_ICAPTCHA_INSECURE` is set (a
+/// runtime escape hatch for integration tests) the function also trusts
+/// `http://127.0.0.1` and `http://localhost` so the full iCaptcha retry path
+/// can be exercised against a local mockito server.
 fn is_https(u: &str) -> bool {
-    reqwest::Url::parse(u)
-        .map(|p| p.scheme() == "https")
-        .unwrap_or(false)
+    let Ok(parsed) = reqwest::Url::parse(u) else {
+        return false;
+    };
+    if parsed.scheme() == "https" {
+        return true;
+    }
+    if std::env::var_os("GITLAWB_ICAPTCHA_INSECURE").is_some()
+        && parsed.scheme() == "http"
+        && matches!(parsed.host_str(), Some("127.0.0.1" | "localhost"))
+    {
+        return true;
+    }
+    false
 }

-/// Lowercased host of a URL, if it parses and has one.
-fn host_of(u: &str) -> Option<String> {
-    reqwest::Url::parse(u)
-        .ok()
-        .and_then(|p| p.host_str().map(|h| h.to_ascii_lowercase()))
+/// Lowercased origin string (`scheme://host[:port]`) of a URL.
+///
+/// Includes the effective port so that `http://localhost:3000` and
+/// `http://localhost:9000` are treated as distinct origins — a hostile node
+/// cannot redirect the iCaptcha solve to a different loopback port.
+fn origin_key(u: &str) -> Option<String> {
+    let parsed = reqwest::Url::parse(u).ok()?;
+    let scheme = parsed.scheme();
+    let host = parsed.host_str()?.to_ascii_lowercase();
+    let port = parsed
+        .port_or_known_default()
+        .map(|p| format!(":{p}"))
+        .unwrap_or_default();
+    Some(format!("{scheme}://{host}{port}"))
 }

 /// Decide which iCaptcha origin to actually talk to, and whether it is trusted
@@ -109,12 +134,13 @@ fn host_of(u: &str) -> Option<String> {
 /// exfiltrated to an origin the operator did not choose.
 fn resolve_solver_url(advertised: Option<&str>, operator: Option<&str>) -> (String, bool) {
    let operator = operator.filter(|u| is_https(u));
-    let operator_host = operator.and_then(host_of);
-    let default_host = host_of(DEFAULT_URL);
+    let operator_origin = operator.as_ref().and_then(|u| origin_key(u));
+    let default_origin = origin_key(DEFAULT_URL);

-    let allowed = |host: &Option<String>| -> bool {
-        host.as_ref()
-            .map(|h| Some(h) == default_host.as_ref() || Some(h) == operator_host.as_ref())
+    let allowed = |origin: &Option<String>| -> bool {
+        origin
+            .as_ref()
+            .map(|o| Some(o) == default_origin.as_ref() || Some(o) == operator_origin.as_ref())
            .unwrap_or(false)
    };

@@ -125,7 +151,7 @@ fn resolve_solver_url(advertised: Option<&str>, operator: Option<&str>) -> (Stri
    };

    let chosen = match advertised {
-        Some(a) if is_https(a) && allowed(&host_of(a)) => a.to_string(),
+        Some(a) if is_https(a) && allowed(&origin_key(a)) => a.to_string(),
        Some(a) => {
            tracing::warn!(
                advertised = %a,
@@ -137,7 +163,7 @@ fn resolve_solver_url(advertised: Option<&str>, operator: Option<&str>) -> (Stri
    };

    // Key goes only to the operator's own configured origin.
-    let key_trusted = operator_host.is_some() && host_of(&chosen) == operator_host;
+    let key_trusted = operator_origin.is_some() && origin_key(&chosen) == operator_origin;
    (chosen, key_trusted)
 }

@@ -201,6 +227,10 @@ pub struct Challenge {
    pub difficulty: u32,
    pub prompt: String,
    pub token: String,
+    /// Proof-of-work to solve and echo back as `powNonce` on the answer. Present
+    /// only when the service has PoW enabled; absent/None means no PoW required.
+    #[serde(default)]
+    pub pow: Option<pow::PowChallenge>,
 }

 #[derive(Debug, Deserialize)]
@@ -237,7 +267,28 @@ pub fn obtain_proof(cfg: &IcaptchaCfg, solver: Option<&Solver>) -> Result<String
                )
            })?;

-        match submit_answer(&client, cfg, &challenge.token, &answer)? {
+        // Solve the proof-of-work bound to this challenge, if the service
+        // requires one. A required-but-unsolvable PoW (unknown algorithm or a
+        // difficulty above our cap) is a hard error — submitting without it
+        // would just be rejected.
+        let pow_nonce = match &challenge.pow {
+            Some(p) => Some(pow::solve(p).ok_or_else(|| {
+                anyhow!(
+                    "cannot solve iCaptcha proof-of-work (algorithm '{}', difficulty {})",
+                    p.algorithm,
+                    p.difficulty
+                )
+            })?),
+            None => None,
+        };
+
+        match submit_answer(
+            &client,
+            cfg,
+            &challenge.token,
+            &answer,
+            pow_nonce.as_deref(),
+        )? {
            AnswerResult::Passed { proof } => return Ok(proof),
            AnswerResult::Continue { challenge: next } => challenge = next,
            AnswerResult::Failed { reason } => {
@@ -273,11 +324,14 @@ fn submit_answer(
    cfg: &IcaptchaCfg,
    token: &str,
    answer: &str,
+    pow_nonce: Option<&str>,
 ) -> Result<AnswerResult> {
    let url = format!("{}/v1/answer", cfg.url.trim_end_matches('/'));
-    let mut req = client
-        .post(&url)
-        .json(&json!({ "token": token, "answer": answer }));
+    let mut body = json!({ "token": token, "answer": answer });
+    if let Some(nonce) = pow_nonce {
+        body["powNonce"] = json!(nonce);
+    }
+    let mut req = client.post(&url).json(&body);
    if let Some(key) = &cfg.api_key {
        req = req.bearer_auth(key);
    }
@@ -320,6 +374,37 @@ fn interactive_prompt(challenge: &Challenge) -> Option<String> {
 #[cfg(test)]
 mod tests {
    use super::*;
+    use std::ffi::OsString;
+    use std::sync::{Mutex, MutexGuard};
+
+    /// Serializes tests that touch the process-global
+    /// `GITLAWB_ICAPTCHA_INSECURE` env var so they never race.
+    static ICAPTCHA_ENV_LOCK: Mutex<()> = Mutex::new(());
+
+    /// Set `GITLAWB_ICAPTCHA_INSECURE` for the test lifetime, restoring any
+    /// prior value on drop.
+    struct InsecureEnv {
+        _lock: MutexGuard<'static, ()>,
+        prev: Option<OsString>,
+    }
+
+    impl InsecureEnv {
+        fn new() -> Self {
+            let lock = ICAPTCHA_ENV_LOCK.lock().unwrap();
+            let prev = std::env::var_os("GITLAWB_ICAPTCHA_INSECURE");
+            std::env::set_var("GITLAWB_ICAPTCHA_INSECURE", "1");
+            InsecureEnv { _lock: lock, prev }
+        }
+    }
+
+    impl Drop for InsecureEnv {
+        fn drop(&mut self) {
+            match self.prev.take() {
+                Some(v) => std::env::set_var("GITLAWB_ICAPTCHA_INSECURE", v),
+                None => std::env::remove_var("GITLAWB_ICAPTCHA_INSECURE"),
+            }
+        }
+    }

    // ── P1: hostile error bodies must not reach the terminal raw ──────────

@@ -403,4 +488,20 @@ mod tests {
        assert_eq!(url, DEFAULT_URL);
        assert!(!key_trusted);
    }
+
+    #[test]
+    fn rejects_insecure_advertised_url_on_different_port() {
+        // With GITLAWB_ICAPTCHA_INSECURE=1, two loopback URLs on different
+        // ports must be treated as distinct origins so a hostile node cannot
+        // redirect the bearer key to a different listener on localhost.
+        let _env = InsecureEnv::new();
+
+        let op = "http://localhost:3000";
+        let (url, key_trusted) = resolve_solver_url(Some("http://localhost:9000"), Some(op));
+        assert_eq!(
+            url, op,
+            "must fall back to operator origin, not use different port"
+        );
+        assert!(key_trusted, "key stays trusted with operator origin");
+    }
 }
@@ -0,0 +1,130 @@
+//! Proof-of-work solver for the iCaptcha answer step.
+//!
+//! iCaptcha requires a small proof-of-work with each answer so that minting a
+//! proof costs CPU — a per-proof cost a distributed abuser cannot dodge by
+//! rotating IPs. The work is bound to the per-challenge id: find a `nonce` such
+//! that `sha256("{challenge}:{nonce}")` has at least `difficulty` leading zero
+//! bits. This mirrors `icaptcha/src/pow.ts`.
+//!
+//! At the service default (~20 bits) this is well under a second for a single
+//! solve; we still cap the search so a hostile/misconfigured difficulty can
+//! never hang the client.
+
+use sha2::{Digest, Sha256};
+
+/// PoW parameters advertised by the service in a challenge (mirrors the
+/// service's `PowChallenge`).
+#[derive(Debug, Clone, serde::Deserialize)]
+pub struct PowChallenge {
+    /// Only `sha256-leading-zero-bits` is understood; other algorithms are
+    /// rejected by [`solve`] rather than silently mis-solved.
+    pub algorithm: String,
+    /// The string to hash against (the per-challenge id).
+    pub challenge: String,
+    /// Required leading zero bits.
+    pub difficulty: u32,
+}
+
+/// Hard cap on nonce search iterations. 2^26 ≈ 67M keeps a ~20-bit target (~1M
+/// expected hashes) comfortably solvable while bounding worst-case work if the
+/// service ever advertises an unexpectedly high difficulty.
+const MAX_ITERS: u64 = 1 << 26;
+
+const ALGORITHM: &str = "sha256-leading-zero-bits";
+
+/// Leading zero bits of a byte slice.
+fn leading_zero_bits(bytes: &[u8]) -> u32 {
+    let mut bits = 0;
+    for &b in bytes {
+        if b == 0 {
+            bits += 8;
+        } else {
+            bits += b.leading_zeros();
+            break;
+        }
+    }
+    bits
+}
+
+/// sha256(`{challenge}:{nonce}`).
+fn pow_hash(challenge: &str, nonce: &str) -> [u8; 32] {
+    let mut hasher = Sha256::new();
+    hasher.update(challenge.as_bytes());
+    hasher.update(b":");
+    hasher.update(nonce.as_bytes());
+    hasher.finalize().into()
+}
+
+/// Solve the PoW, returning a nonce whose hash meets the difficulty. Returns
+/// `None` for an unknown algorithm or if no nonce is found within the cap (a
+/// difficulty far above what the service uses in practice).
+pub fn solve(pow: &PowChallenge) -> Option<String> {
+    if pow.algorithm != ALGORITHM {
+        tracing::warn!(algorithm = %pow.algorithm, "unknown iCaptcha PoW algorithm; cannot solve");
+        return None;
+    }
+    if pow.difficulty == 0 {
+        return Some("0".to_string());
+    }
+    for i in 0..MAX_ITERS {
+        let nonce = format!("{i:x}");
+        if leading_zero_bits(&pow_hash(&pow.challenge, &nonce)) >= pow.difficulty {
+            return Some(nonce);
+        }
+    }
+    tracing::warn!(
+        difficulty = pow.difficulty,
+        max_iters = MAX_ITERS,
+        "iCaptcha PoW not solved within iteration cap"
+    );
+    None
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn pow(challenge: &str, difficulty: u32) -> PowChallenge {
+        PowChallenge {
+            algorithm: ALGORITHM.to_string(),
+            challenge: challenge.to_string(),
+            difficulty,
+        }
+    }
+
+    #[test]
+    fn leading_zero_bits_counts_across_bytes() {
+        assert_eq!(leading_zero_bits(&[0xff]), 0);
+        assert_eq!(leading_zero_bits(&[0x7f]), 1);
+        assert_eq!(leading_zero_bits(&[0x01]), 7);
+        assert_eq!(leading_zero_bits(&[0x00, 0xff]), 8);
+        assert_eq!(leading_zero_bits(&[0x00, 0x01]), 15);
+    }
+
+    #[test]
+    fn solves_and_the_solution_verifies() {
+        let p = pow("challenge-abc", 12);
+        let nonce = solve(&p).expect("should solve a 12-bit target");
+        assert!(leading_zero_bits(&pow_hash(&p.challenge, &nonce)) >= 12);
+    }
+
+    #[test]
+    fn solution_is_bound_to_the_challenge() {
+        // A nonce solving one challenge should (overwhelmingly) not solve another
+        // at the same difficulty — the work is challenge-specific.
+        let nonce = solve(&pow("challenge-A", 12)).unwrap();
+        assert!(leading_zero_bits(&pow_hash("challenge-B", &nonce)) < 12);
+    }
+
+    #[test]
+    fn rejects_unknown_algorithm() {
+        let mut p = pow("c", 8);
+        p.algorithm = "scrypt".to_string();
+        assert!(solve(&p).is_none());
+    }
+
+    #[test]
+    fn zero_difficulty_is_trivially_solved() {
+        assert_eq!(solve(&pow("c", 0)).as_deref(), Some("0"));
+    }
+}
@@ -120,7 +120,7 @@ Positive:
 Risks:

 - Many commands default to the public node; `git-remote-gitlawb` defaults to localhost. This split should be called out in README examples.
- `gl sync trigger` signs the request when a local identity is available and falls back to the legacy unsigned request for live compatibility.
+- `gl sync trigger` requires a local identity and always sends a signed request; the `/api/v1/sync/trigger` route rejects unsigned calls, so the command fails locally when no identity is configured.
 - Several CLI commands parse dynamic JSON responses permissively; good for compatibility, but error messages can hide response-shape regressions.

 ## CI and release readiness
@@ -38,6 +38,16 @@ primary_region = "iad"
    # slots (hard_limit) — root factor in the 2026-06-12 prod outage
    idle_timeout = 120

+  [[http_service.checks]]
+    # Gate routing (and deploys) on real readiness: /ready probes the DB, so a
+    # node stuck retrying a dead or misconfigured database is never routed to,
+    # and a deploy with a bad DATABASE_URL fails visibly instead of going green.
+    interval = "15s"
+    timeout = "5s"
+    grace_period = "75s"
+    method = "GET"
+    path = "/ready"
+
 [[services]]
  protocol = "udp"
  internal_port = 7546