docs: date the 2.0.9 entry for its release

2.0.9 taught the shim to drop a leading U+FEFF but left setup.mjs parsing raw.
Both programs read the same mirror.json and bundle.json, so a BOM made one file
mean different things: the shim found the checkout, setup did not — and a
mirrored setup re-mirrored the previous manifest and provisioned from it.
bundle.json was read as "nothing is provisioned" for the same reason.

Both sides now use the same readJson(). verify-branch.ps1 and CI fail on a bare
JSON.parse(readFileSync(...)) in either file, and two tests cover a BOM-ed
mirror.json and a BOM-ed bundle.json; both fail without the strip (checked).

.github/workflows/validate.yml

@@ -51,6 +51,53 @@ jobs:
         # and a drifted floor drops hosts the README still lists.
         run: node scripts/host-compat.mjs
 
+      - name: The READMEs quote the declared DSH range verbatim
+        # The same comparison verify-branch.ps1 makes locally. Without it here, a
+        # stale quote survives every CI signal: the JSON, host-compat and the
+        # audit all agree while the sentence a human reads names another ceiling
+        # (that is how `<0.3.0` outlived the move to `<0.3.0-0`).
+        run: |
+          node -e "
+            const p = require('./package.json');
+            const { readFileSync } = require('fs');
+            const fail = (m) => { console.error('FAIL: ' + m); process.exit(1) };
+            for (const doc of ['README.md', 'README.zh-CN.md']) {
+              const text = readFileSync(doc, 'utf8');
+              if (!text.includes(p.engines.dsh)) fail(doc + ' does not quote engines.dsh (' + p.engines.dsh + ')');
+              // The pin example is copy-pasteable: it must name the version this
+              // tree publishes, or the reader gets a ref that does not exist.
+              if (!text.includes('dsh-plugin-rea#v' + p.version)) fail(doc + ' does not pin dsh-plugin-rea#v' + p.version);
+            }
+            console.log('readme range ok');
+          "
+
+      - name: Both JSON readers tolerate a BOM
+        # verify-branch.ps1 runs the same check locally. bin/rea-shim.mjs and
+        # scripts/setup.mjs read the same mirror.json/bundle.json, so a strip on
+        # one side only makes the same file say "there is a checkout" to the shim
+        # and "there is none" to setup — which shipped once: setup re-mirrored the
+        # previous manifest. A bare JSON.parse(readFileSync(...)) is that bug.
+        run: |
+          node - <<'JS'
+          const { readFileSync } = require('node:fs');
+          const blind = [];
+          for (const file of ['bin/rea-shim.mjs', 'scripts/setup.mjs']) {
+            const text = readFileSync(file, 'utf8');
+            for (const m of text.matchAll(/JSON\.parse\(\s*readFileSync\(/g)) {
+              // readJson() itself is the strip; anything else must not parse a file raw.
+              if (!/replace\(/.test(text.slice(m.index, m.index + 200))) {
+                blind.push(file + ':' + text.slice(0, m.index).split('\n').length);
+              }
+            }
+            if (!text.includes('replace(/^\\uFEFF/')) blind.push(file + ': no U+FEFF strip');
+          }
+          if (blind.length) {
+            console.error('FAIL: BOM-blind JSON read at ' + blind.join(', '));
+            process.exit(1);
+          }
+          console.log('bom-blind reads: none');
+          JS
+
       - name: JSON files parse
         run: |
           node -e "

CHANGELOG.md

@@ -2,6 +2,84 @@
 
 本插件遵循语义化版本。版本号变化说明「配置组合」这层的变化，与 REA 自身的版本无关。
 
+## 2.0.9 — 2026-10-18
+
+**2.0.8 的两处发布前问题（假回退、乱码）与若干文档缺口；不改正常路径，只让失败路径说真话。**
+
+### 修复
+
+- **`reexecFromCheckout` 的「回退」是假话**：spawn 失败时只打印「继续用镜像副本」，函数却返回了，`main()` 已经
+  return —— 没有 `exit` 事件、事件循环排空、进程以 **exit 0 静默退出**，行看起来启动成功却没有任何工具。现在这个
+  Promise **只在没接管时才 resolve**：子进程活着时本进程等待、由子进程的退出码决定；失败则 `main()` 继续用本地副本
+  启动，并如实说明在回退。
+- **回退覆盖了升级竞态的主形态**：`spawn` 的目标是 `process.execPath`，spawn 级失败几乎只剩资源耗尽；真正常见的是
+  「哈希比对通过 → node 启动 → 文件已被换掉」→ node 以 `MODULE_NOT_FOUND` 退 1。现在**退出码非 0 且源文件已不存在**
+  时同样回退到本地副本（窗口毫秒级，代价是一次 `stat`），不再把竞态变成一行死掉的 MCP。
+- **乱码 `鈥?` 混进用户可见输出**：2.0.7 在 GBK 编辑器里碰过 `bin/rea-shim.mjs`，16 处破折号被写成 `鈥?`，其中两条是
+  stderr 消息（首次自动供给、上次供给失败）—— 每个用户都会看到。全部还原为 `— `（含被吃掉的空格）。
+- **开发时可能测到「已安装插件」而不是自己的改动**：checkout 副本会顺着 bundle 的 `mirror.json` 转发到插件目录。
+  现在 checkout（带 `cordis.patch.yml`）永不转发，只有镜像副本会；注释也改成与行为一致。
+- **带 BOM 的 `mirror.json` / `bundle.json` 被当成「没有记录」**：`JSON.parse` 拒绝前导 BOM，而每个调用方都把解析失败
+  读成「无记录」。Windows 编辑器保存的 JSON 就会带 BOM，表现是镜像自愈静默不生效、bundle 被当成未供给。`bin/rea-shim.mjs`
+  与 `scripts/setup.mjs` 现在都经各自的 `readJson()` 去掉 `U+FEFF` 再解析。**两个文件读的是同一份记录，所以缺一不可**：
+  此前只有 shim 剥了 BOM，带 BOM 的 `mirror.json` 在 setup 眼里仍是「没有 checkout」，镜像 layout 下的 setup 于是把上一版
+  manifest 又镜了一遍并从它供给；`bundle.json` 同理被读成未供给。`verify-branch.ps1` 与 CI 都加了守卫：这两个文件里
+  出现裸的 `JSON.parse(readFileSync(...))` 即失败。
+
+### 文档 / CI
+
+- 两份 README 的钉版本示例改为**当前版本** `#v2.0.9`（2.0.8 那一轮已从 `#v2.0.0` 提到 `#v2.0.8`，版本号一动就得跟上，
+  否则读者拿到的 ref 不存在）；README 的「机器上已有 REA」一节补上 Windows 限制：**强制结束 shim 不会带走被委派的 REA**。
+- `docs/bundle-design.md`（随包发布）补上 2.0.7 的 launch mode 与 2.0.8 的镜像自愈，含 `mirror.json` 的
+  `shimSha256` / `pluginVersion` / `dshHome` 三个字段与控制流图。
+- CI 新增两条：README 必须逐字引用 `engines.dsh`；README 的钉版本示例必须等于 `package.json` 的 version（`verify-branch.ps1`
+  同步加了第二条，避免同一个漂移第三次发生）。
+- `systemReaCandidates` 的去重键改用传入的 `platform` 参数（测试缝一致，生产无变化）。
+
+### 验证
+
+- 单测 **71 条**（68 过 + 3 平台跳过；新增「checkout 副本不转发」「文件中途消失 → 回退」「带 BOM 的 `mirror.json`」
+  「带 BOM 的 `bundle.json`」四条）；镜像转发测试改为真的运行镜像副本。
+- `verify-branch.ps1` 44 项全绿；`audit-manifest` clean；`host-compat` 10 covered / 5 outside。
+
+## 2.0.8 — 2026-10-18
+
+**2.0.7 的启动检测在两种边界上会失控：一个包着本 shim 的 `rea` 会让探针递归成进程链；超时探针会漏掉一个孙进程。两条都已修，并补了复现测试。**
+
+### 修复
+
+- **重复注册检测在自定义 `DSH_HOME` 下失效**：harness 会从 MCP 子进程里抹掉所有 `DSH_*`，镜像副本因此读
+  `~/.dsh` —— 那是错的文件，上游写进真实 home 的第二条 `serverName: rea` 永远报不出来。`setup.mjs` 现在把运行时
+  的 home 记进 `mirror.json` 的 `dshHome`，shim 优先读环境、其次读这条记录。`check-updates.ps1` 的 profile 段也
+  改用同一条 home 规则（此前硬编码 `$env:USERPROFILE`，自定义 home 时报「找不到 profile」）。
+- **镜像启动器不会自己更新**：行执行的是 `<DSH_HOME>/plugins/rea-bundle/bin/rea-shim.mjs` 这份**副本**，而市场升级
+  只换包、不跑 setup —— 副本会一直跑它被复制时的代码，于是新版本里的修复对老用户静默失效（旧副本照常工作，最难发现）。
+  现在镜像启动时会与 `mirror.json` 记录的插件目录比对哈希，不同就转发执行插件里的那一份（一跳，带
+  `REA_BUNDLE_SHIM_REEXEC` 守卫，且只从镜像指向插件，不会反向）。`--shim-status` 新增 `mirror.stale`，
+  `check-updates.ps1` 也会报「镜像落后，重跑 setup」；`mirror.json` 增加 `shimSha256` 与 `pluginVersion` 便于追溯。
+  **2.0.8 之前的版本自身无法完成这一步**（副本里没有这段代码），从那些版本升级仍需手动跑一次 setup。
+- **探针递归**：`probeRea` 派生候选时没带 `REA_BUNDLE_DELEGATED=1`，而防自委派的守卫只在**委派**前生效。若 PATH 上是「调用本 shim 的 wrapper」，
+  探针 → wrapper → 新 shim → 再探针……实测并发 node 峰值 83+、杀掉后仍自我再生。现在探针环境同时带 `REA_BUNDLE_DELEGATED=1` 与
+  `REA_BUNDLE_AUTO_PROVISION=0`：嵌套运行直接走 bundle 并返回，实测 0.2 秒、零额外进程。
+- **超时探针泄漏孙进程**：`spawnSync` 的超时只杀它自己启动的 cmd.exe，而 `taskkill /T` 在 `spawnSync` 回收之后调用已找不到父进程 ——
+  每次超时留一个 REA/ping 在跑。探针改为异步 `spawn` + 自己的计时器：超时发生在父进程仍存活时，`taskkill /T /F` 能真正清掉整棵树。
+  实测 8.3 秒放弃、`rejected=["timeout"]`、无残留进程。
+- **Windows 信号处理器是死代码**：`child.kill("SIGTERM")` 在 Windows 上是 TerminateProcess，不可捕获；控制台的 Ctrl+C 又直达子进程。
+  该分支已删除，并如实写明限制：**在 Windows 上强制结束 shim 不会带走被委派的 REA**（Node 没有 job object 可用）。
+- **`comspec()` 不校验**：`ComSpec` 指向不存在的文件时，正常的 `.cmd` REA 被判 `spawn-failed`（`auto` 静默退回 bundle，`system` 直接 78）。
+  现在校验为常规文件，否则回落到 `%SystemRoot%\System32\cmd.exe`；实测 `ComSpec` 指向不存在路径仍能识别 6.9.0。
+- **文案**：显式路径是目录时报「does not exist」，改为「is not a file」。
+
+### 验证
+
+- 单测 **67 条**（2.0.7 是 60 条，本轮 +7：wrapper 递归必须被判为 `exit 78` 且 20 秒内收敛；`ComSpec` 失效仍识别 `.cmd` REA；
+  镜像自愈的转发/守卫/`stale` 上报/同内容不转发；`DSH_HOME` 被抹时从 `mirror.json` 找到真实 home 并报出重复注册）：
+  Windows 64 过 + 3 平台跳过。
+- `verify-branch.ps1` 全绿（39 项），含「两份 README 必须写出 package.json 里的 `engines.dsh` 原文」；`audit-manifest` clean；
+  `host-compat` 10 covered / 5 correctly outside。
+- 手工复现三例：wrapper 递归 0.2 秒收敛、0 残留进程；挂起候选 8.3 秒放弃且无 `PING` 残留；`ComSpec` 指向空路径仍识别系统 REA。
+
+
 ## 2.0.7 — 2026-10-18
 
 **机器上已有可用的 REA 时，2.x 直接按 1.x 的方式跑它（环境检测 + 委派），不再供给；同时把 2.0.6 的宿主声明收紧到真的能证明的范围。**

README.md

@@ -100,7 +100,7 @@ releases, checksum-verified). Then install the plugin for your profile:
 ```
 dsh plugin --profile <profile> add dsh-plugin-rea
 # or pin this release instead of tracking npm latest:
-dsh plugin --profile <profile> add github:czcdr/dsh-plugin-rea#v2.0.0
+dsh plugin --profile <profile> add github:czcdr/dsh-plugin-rea#v2.0.9
 ```
 
 > **On an Electron host (the DeepSeek Harness desktop app) the profile is owned by the application.**
@@ -127,7 +127,7 @@ by the shim itself, which provisions in the background.
 
 ### Which DSH versions
 
-`package.json` declares `engines.dsh: ">=0.1.7-rc.2 <0.3.0"`, and that declaration is the answer the plugin market
+`package.json` declares `engines.dsh: ">=0.1.7-rc.2 <0.3.0-0"`, and that declaration is the answer the plugin market
 reads: with it the card says **compatible**; without it the market can only say *unknown*. The range is not a guess —
 it is the dsh release list this plugin is checked against, and `node scripts/host-compat.mjs` fails the build when the
 two disagree:
@@ -161,6 +161,9 @@ runs **that**, exactly as the 1.x line did, and nothing is provisioned:
   list says why a candidate was skipped (`"exit 7"`, `"inside the bundle"`, `"timeout"`).
 - A delegated child carries `REA_BUNDLE_DELEGATED=1`, so a wrapper that calls this shim cannot make it delegate to
   itself forever.
+- **On Windows a forced kill of the shim does not reap the delegated REA.** There is no job object here: Task Manager
+  or a supervisor terminating the shim leaves your `rea` running with the row's pipes (a console Ctrl+C reaches the
+  whole process group and does stop it). On POSIX the child is in the same group and dies with the terminal.
 
 ## Configure — nothing
 
@@ -230,9 +233,9 @@ Which one? Upstream's is the configuration-only route: it expects Node on REA's
 zero-dependency route: it fetches Node, REA, JDK and Ghidra on first run. The patch shape and the
 `mcp__rea__*` surface are the same either way.
 
-The shim reports the conflict on startup when it can see that file — a custom `DSH_HOME` is hidden
-from an MCP child, so it falls back to `~/.dsh` there — and `node bin/rea-shim.mjs --shim-status`
-lists it under `duplicateRegistration`.
+The shim reports the conflict on startup — `setup.mjs` records the DSH home it ran under in
+`mirror.json`, and the mirrored copy reads that when the harness has stripped `DSH_*` from its
+environment; `node bin/rea-shim.mjs --shim-status` lists it under `duplicateRegistration`.
 
 ## Verify
 
@@ -337,6 +340,12 @@ back on the next start.
 
 - **This plugin** never updates itself. Installed from a market? Update it there. Installed from a `file:`
   checkout? Overwrite the directory and reinstall.
+- **The row runs a COPY of this plugin's launcher.** `<DSH_HOME>/plugins/rea-bundle/bin/rea-shim.mjs` is a mirror
+  made by setup, so a market upgrade replaces the package but not the file the row executes — until setup runs
+  again. From **2.0.8** the mirror notices that the installed plugin ships a different launcher and re-execs it
+  (one hop, guarded by `REA_BUNDLE_SHIM_REEXEC`), so upgrades carry. On an older version the mirror stays behind
+  silently; `--shim-status` now reports `mirror.stale`, and `check-updates.ps1` says to re-run setup. If you are
+  upgrading from 2.0.0–2.0.7, run `node scripts/setup.mjs` once after the upgrade.
 - **Upgrading from `2.0.0-bundle.1`**: that release mirrored the shim and `setup.mjs` but not the manifest,
   and recorded nothing about the plugin checkout, so a bundle it provisioned cannot repair itself — its
   background provisioning dies on the missing manifest, invisibly, and its own lock suppresses retries for

README.zh-CN.md

@@ -94,7 +94,7 @@ profile 安装插件：
 ```
 dsh plugin --profile <profile> add dsh-plugin-rea
 # 或钉住这个版本，而不是跟着 npm latest 走：
-dsh plugin --profile <profile> add github:czcdr/dsh-plugin-rea#v2.0.0
+dsh plugin --profile <profile> add github:czcdr/dsh-plugin-rea#v2.0.9
 ```
 
 > **Electron 宿主（DeepSeek Harness 桌面版）的 profile 由应用独占。** 那种机器上 `dsh plugin --profile desktop …`
@@ -118,7 +118,7 @@ node scripts/setup.mjs --reuse      # 或先 --dry-run 看计划
 
 ### 支持哪些 DSH 版本
 
-`package.json` 里声明了 `engines.dsh: ">=0.1.7-rc.2 <0.3.0"`，这就是插件市场读的那句话：有它，卡片显示
+`package.json` 里声明了 `engines.dsh: ">=0.1.7-rc.2 <0.3.0-0"`，这就是插件市场读的那句话：有它，卡片显示
 **兼容**；没有它，市场只能说*未声明*。这个范围不是猜的——它对应本插件实际核对过的 dsh 发布列表，
 `node scripts/host-compat.mjs` 会在两者不一致时让构建失败：
 
@@ -149,6 +149,9 @@ node scripts/setup.mjs --reuse      # 或先 --dry-run 看计划
 - `--shim-status` 会把判断结果打出来 —— `launch.mode`、`launch.reason`、`launch.systemRea`，`launch.rejected` 里
   写的是每个候选被跳过的原因（`"exit 7"`、`"inside the bundle"`、`"timeout"`）。
 - 被委派的子进程带着 `REA_BUNDLE_DELEGATED=1`，所以一个调用本 shim 的 wrapper 不会让它无限委派给自己。
+- **Windows 上强制结束 shim 不会带走被委派的 REA**：这里没有 job object，任务管理器或 supervisor 终止 shim 时，
+  你自己的 `rea` 会继续占着这一行的管道（控制台 Ctrl+C 会发给整个进程组，那种情况下会一起停）。POSIX 上子进程
+  在同一进程组，随终端一起退出。
 
 ## 配置 —— 不需要
 
@@ -216,8 +219,8 @@ duplicate server name 报错并加载失败，最终留下哪一行取决于加
 自己准备。本包是零依赖路线：首次运行自动取 Node、REA、JDK、Ghidra。两者的 patch 形态与
 `mcp__rea__*` 工具面相同。
 
-shim 在能看到该文件时会在启动时提示冲突 —— MCP 子进程里拿不到自定义 `DSH_HOME`，那种情况下它会
-退回 `~/.dsh`；`node bin/rea-shim.mjs --shim-status` 会把冲突列在 `duplicateRegistration` 下。
+shim 会在启动时提示冲突 —— `setup.mjs` 会把运行时的 DSH home 记进 `mirror.json`，镜像副本在 harness 抹掉
+`DSH_*` 之后就用这条记录去找那份文件；`node bin/rea-shim.mjs --shim-status` 会把冲突列在 `duplicateRegistration` 下。
 
 ## 验证
 
@@ -314,6 +317,11 @@ node scripts/setup.mjs          # 或：powershell -File scripts\rea-bundle-boot
 工具就回来了。
 
 - **本插件**从不自更新。从市场装的就在市场更新；从 `file:` 检出的就覆盖目录重装。
+- **行跑的是本插件启动器的「镜像副本」**：`<DSH_HOME>/plugins/rea-bundle/bin/rea-shim.mjs` 是 setup 复制过去的，
+  所以市场升级只换包、不换行执行的那个文件 —— 直到再跑一次 setup。从 **2.0.8** 起，镜像会发现自己落后于已安装的
+  插件，并转发执行插件里的那一份（一跳，带 `REA_BUNDLE_SHIM_REEXEC` 守卫），升级因此能生效。更早的版本里镜像会
+  静默地停在旧代码；`--shim-status` 现在会报 `mirror.stale`，`check-updates.ps1` 也会提示重跑 setup。**从
+  2.0.0–2.0.7 升级的话，升级后跑一次 `node scripts/setup.mjs`。**
 - **从 `2.0.0-bundle.1` 升级**：那一版镜像了 shim 与 `setup.mjs`，却漏了 manifest，也没有留下插件 checkout
   的记录，所以它供给出来的 bundle **无法自愈** —— 后台供给会因缺 manifest 而崩溃且完全不可见，而它自己写下的
   lock 又会让重试被抑制六小时。请**从插件目录**重跑一次 `node scripts/setup.mjs`：它会重新镜像三个文件，

bin/rea-shim.mjs

@@ -1,6 +1,6 @@
 #!/usr/bin/env node
 /**
- * rea-shim 鈥?the process the DSH MCP row launches.
+ * rea-shim — the process the DSH MCP row launches.
  *
  * Why this exists: the published `cordis.patch.yml` must carry no machine path,
  * yet REA needs absolute paths for every dependency. The shim is the seam: it
@@ -10,11 +10,12 @@
  * It downloads nothing, writes nothing, and never touches PATH.
  *
  * Exit codes:  0 child exited normally   * child's own status
- *              78 EX_CONFIG  bundle not provisioned (or unusable) 鈥?the row has
+ *              78 EX_CONFIG  bundle not provisioned (or unusable) — the row has
  *                            `failOnStartupError: false`, so the harness stays up
  *                            and the message is the operator's remediation.
  */
 import { spawn, spawnSync } from "node:child_process";
+import { createHash } from "node:crypto";
 import { existsSync, mkdirSync, readFileSync, rmSync, statSync, writeFileSync } from "node:fs";
 import { homedir } from "node:os";
 import path from "node:path";
@@ -25,6 +26,19 @@ const EX_CONFIG = 78;
 const HERE = path.dirname(fileURLToPath(import.meta.url));
 const PLUGIN_ROOT = path.resolve(HERE, "..");
 
+/**
+ * JSON from disk, tolerating the UTF-8 BOM a Windows editor writes.
+ *
+ * `JSON.parse` rejects a leading BOM, and every caller here reads a parse
+ * failure as "no record": a BOM would silently downgrade mirror.json to "no
+ * plugin checkout" and bundle.json to "not provisioned". Measured while testing
+ * this file — a hand-edited mirror.json written by Windows PowerShell behaved
+ * exactly that way.
+ */
+function readJson(file) {
+  return JSON.parse(readFileSync(file, "utf8").replace(/^\uFEFF/, ""));
+}
+
 /** DSH home, by the same rule setup.mjs and the published patch use. */
 function dshHome() {
   const fromEnv = process.env.DSH_HOME;
@@ -32,6 +46,36 @@ function dshHome() {
   return path.join(homedir(), ".dsh");
 }
 
+/**
+ * The DSH home recorded by setup, or null.
+ *
+ * Only the mirrored copy needs this: the harness strips `DSH_*` from an MCP
+ * child, so with a custom home the environment cannot answer. Read once per
+ * process — there is one bundle root per process and this is a startup query.
+ */
+let recordedDshHomeCache = null;
+function recordedDshHome(root) {
+  if (recordedDshHomeCache !== null) return recordedDshHomeCache;
+  let value = null;
+  try {
+    const record = readJson(path.join(root, "mirror.json"));
+    if (typeof record?.dshHome === "string" && record.dshHome.trim() !== "" && path.isAbsolute(record.dshHome)) {
+      value = path.resolve(record.dshHome);
+    }
+  } catch {
+    value = null;
+  }
+  recordedDshHomeCache = value;
+  return value;
+}
+
+/** The home to look in when the environment has been scrubbed. */
+function dshHomeFor(root) {
+  const fromEnv = process.env.DSH_HOME;
+  if (fromEnv && fromEnv.trim() !== "") return path.resolve(fromEnv);
+  return recordedDshHome(root) ?? path.join(homedir(), ".dsh");
+}
+
 /**
  * Where setup writes the machine-local truth.
  *
@@ -43,11 +87,11 @@ function dshHome() {
  *    DSH_HOME: the harness strips every `DSH_*` name from an MCP child's
  *    environment (case-insensitively, because Windows is), so a custom DSH_HOME
  *    would send it to `~/.dsh`, where it would report "not provisioned" for a
- *    bundle sitting right next to it 鈥?and start a second ~800 MB run there.
+ *    bundle sitting right next to it — and start a second ~800 MB run there.
  *  * The **checkout** copy (`<plugin>/bin/rea-shim.mjs`) is what a human runs, e.g.
  *    `npm run bundle:status`, from a shell where DSH_HOME *is* visible. Its own
  *    directory is the plugin, not the bundle, so resolving to itself would report
- *    "not provisioned" on a fully provisioned machine 鈥?and a bare
+ *    "not provisioned" on a fully provisioned machine — and a bare
  *    `node bin/rea-shim.mjs mcp` would provision ~800 MB into the checkout.
  *
  * Only the checkout ships `cordis.patch.yml`, so that file is the discriminator.
@@ -80,11 +124,11 @@ function usableSetup(dir) {
  * The mirrored copy is a snapshot: after a plugin upgrade it still holds the
  * previous manifest, so it would provision the previous versions forever. setup
  * writes <bundle>/mirror.json naming the real checkout; prefer that while it is
- * usable, and fall back to the local copy 鈥?which is also all a first run has.
+ * usable, and fall back to the local copy — which is also all a first run has.
  */
 function provisioningScript(root) {
   try {
-    const record = JSON.parse(readFileSync(path.join(root, "mirror.json"), "utf8"));
+    const record = readJson(path.join(root, "mirror.json"));
     const recorded = usableSetup(record && record.pluginRoot);
     if (recorded) return recorded;
   } catch {
@@ -104,13 +148,16 @@ function provisioningScript(root) {
  *
  * The parse is deliberately small: the two files it cares about are block
  * mappings with one id/serverName per row, and anything it cannot attribute is
- * ignored 鈥?a missed hint is acceptable, a false alarm is not. The mirrored shim
- * cannot see a custom DSH_HOME (the harness strips DSH_* from an MCP child), so
- * this falls back to `~/.dsh` like the rest of the bundle; the row has the same
- * limitation.
+ * ignored — a missed hint is acceptable, a false alarm is not.
+ *
+ * Finding the file is the part that needed care: the harness strips every DSH_*
+ * variable from an MCP child, so a mirrored copy with a custom DSH_HOME used to
+ * read `~/.dsh` — the wrong file, and therefore a conflict it could never report.
+ * `setup.mjs` writes the home it ran under into `mirror.json`, and that record is
+ * what this uses when the environment has nothing to say.
  */
-function foreignReaRegistration() {
-  const patch = path.join(dshHome(), "cordis.patch.yml");
+function foreignReaRegistration(root) {
+  const patch = path.join(dshHomeFor(root), "cordis.patch.yml");
   let text;
   try {
     text = readFileSync(patch, "utf8");
@@ -133,7 +180,7 @@ function foreignReaRegistration() {
 /**
  * The provisioning lock is a small JSON record: { state, pid, at, exit? }.
  * `state: "running"` is written when a run is started (setup's own pid once it
- * exists), and the failing run rewrites it as `state: "failed"` 鈥?it is kept on
+ * exists), and the failing run rewrites it as `state: "failed"` — it is kept on
  * purpose so a broken setup cannot be re-downloaded in a loop. A legacy
  * plain-number lock is still honoured as "running".
  */
@@ -171,7 +218,7 @@ function pidAlive(pid) {
  * a killed attempt is simply continued on the next start.
  *
  * Set REA_BUNDLE_AUTO_PROVISION=0 to require an explicit `setup.mjs` run.
- * Returns { started, reason, logPath } 鈥?the caller words its message from
+ * Returns { started, reason, logPath } — the caller words its message from
  * `reason`, because "provisioning started in the background" was also printed
  * for a lock left behind by a run that had already failed, and for one whose
  * process was long gone.
@@ -208,7 +255,7 @@ function maybeAutoProvision(root) {
     // Reached when the lock is older than the freshness window, or its holder is
     // gone and never wrote an outcome (harness restart, power loss, a kill): what
     // it records is not happening any more. This removal is the whole point of the
-    // freshness rule 鈥?without it the exclusive create below failed with EEXIST
+    // freshness rule — without it the exclusive create below failed with EEXIST
     // *forever*, auto-provisioning never ran again, and main() printed nothing at
     // all for that outcome. The lock's own "honour it only while it is fresh"
     // comment described behaviour the code did not have.
@@ -265,7 +312,7 @@ function fail(message, detail) {
   if (detail) lines.push("", "  detail: " + detail);
   // Point at the real checkout when the record allows it: running the mirrored
   // copy is fine, but it can only ever provision the manifest it was mirrored
-  // with 鈥?and a bundle mirrored before the manifest travelled with it has no
+  // with — and a bundle mirrored before the manifest travelled with it has no
   // usable copy at all, so the honest answer is then "run the plugin's own script".
   const root = bundleRoot();
   const setupScript = provisioningScript(root);
@@ -299,7 +346,7 @@ function readBundleConfig(root) {
   if (!existsSync(file)) return { ok: false, code: "missing", file };
   let parsed;
   try {
-    parsed = JSON.parse(readFileSync(file, "utf8"));
+    parsed = readJson(file);
   } catch (error) {
     return { ok: false, code: "malformed", file, detail: String(error && error.message) };
   }
@@ -316,7 +363,7 @@ function resolveRea(config, root) {
   // The fallback has to match where setup actually installs the package:
   // `npm install --prefix <root>/vendor` resolves into vendor/node_modules, so a
   // fallback without that segment named a directory that never exists. It only
-  // fires when an older bundle.json has no paths.reaEntry 鈥?which is exactly when
+  // fires when an older bundle.json has no paths.reaEntry — which is exactly when
   // a wrong fallback turns a usable install into "the vendored REA CLI is gone".
   const reaEntry = paths.reaEntry
     ?? path.join(root, "vendor", "node_modules", "rea-agents", "scripts", "rea.mjs");
@@ -373,7 +420,7 @@ function childEnvironment(config) {
  * the machine already has one, the honest thing to do is run it.
  *
  * The 1.x line was exactly that: `rea mcp` off PATH, user-managed Node and
- * Ghidra. So "use the system install" is not a new code path invented here 鈥?it
+ * Ghidra. So "use the system install" is not a new code path invented here — it
  * is the 1.x contract, reachable from the 2.x row. `auto` (the default) prefers
  * the system install and falls back to the provisioned bundle; `bundle` pins the
  * old behaviour; `system` insists (and fails loudly instead of provisioning
@@ -432,7 +479,7 @@ function systemReaNames(platform = process.platform) {
 /**
  * Every path worth probing, most explicit first.
  *
- * `REA_BUNDLE_SYSTEM_REA` names one binary outright 鈥?that is both the test
+ * `REA_BUNDLE_SYSTEM_REA` names one binary outright — that is both the test
  * seam and a real operator need (an install that is not on the harness's PATH,
  * which on Desktop is not the user's shell PATH).
  */
@@ -454,7 +501,9 @@ function systemReaCandidates({ env = process.env, platform = process.platform }
   }
   const seen = new Set();
   return candidates.filter((candidate) => {
-    const key = process.platform === "win32" ? candidate.toLowerCase() : candidate;
+    // Keyed on the platform being RESOLVED, not on the one this process happens
+    // to run: the tests pass `platform` to exercise both shapes on one machine.
+    const key = platform === "win32" ? candidate.toLowerCase() : candidate;
     if (seen.has(key)) return false;
     seen.add(key);
     return true;
@@ -516,7 +565,11 @@ function cmdQuote(value) {
  */
 function comspec() {
   const fromEnv = process.env.ComSpec ?? process.env.COMSPEC;
-  if (typeof fromEnv === "string" && fromEnv.trim() !== "") return fromEnv;
+  // A ComSpec that names nothing is a real (if unusual) state, and trusting it
+  // would judge every `.cmd` REA "spawn-failed" — i.e. report the machine as
+  // having no REA because its shell pointer is broken. Fall back to the path
+  // Windows itself would use.
+  if (typeof fromEnv === "string" && fromEnv.trim() !== "" && isFileSync(fromEnv)) return fromEnv;
   const systemRoot = process.env.SystemRoot ?? process.env.SYSTEMROOT ?? "C:\\Windows";
   return path.join(systemRoot, "System32", "cmd.exe");
 }
@@ -527,50 +580,77 @@ function comspec() {
  * A file existing on PATH is not the same as a working install: npx leftovers,
  * half-removed globals and a shim whose Node is gone all sit on PATH and all
  * fail at once. One bounded `--version` separates them, and a slow or hanging
- * answer counts as "not usable" 鈥?the fallback (the bundle) still works, while
+ * answer counts as "not usable" — the fallback (the bundle) still works, while
  * delegating to a broken binary would take the tools down with it.
+ *
+ * Two things here are not incidental:
+ *
+ *  * The probe runs with `REA_BUNDLE_DELEGATED=1`. A candidate that is itself a
+ *    wrapper around this shim would otherwise be probed by a nested shim that
+ *    probes the wrapper — measured: a process chain that keeps respawning
+ *    itself. The flag makes the nested run take the bundle path and return.
+ *  * It is asynchronous, not `spawnSync` with a timeout. `spawnSync` reaps the
+ *    child it started, and its timeout kills only that child: for a `.cmd` shim
+ *    that means cmd.exe dies while the REA inside it keeps running and holds
+ *    the pipes. Killing the TREE is only possible while the parent is alive,
+ *    which means owning the wait ourselves.
  */
 function probeRea(file, { platform = process.platform, timeout = PROBE_TIMEOUT_MS } = {}) {
-  // `existsSync` says nothing about the shape: a DIRECTORY named `rea.cmd` exists,
-  // fails to spawn, and would be reported as a broken install instead of as a
-  // name collision. Only a regular file is a candidate.
-  try {
-    if (!statSync(file).isFile()) return { ok: false, reason: "not a file" };
-  } catch {
-    return { ok: false, reason: "missing" };
-  }
-  const command = [file, "--version"];
-  // `cmd /d /s /c "<line>"`: Windows only. Two details are load-bearing.
-  // `/s` strips the first and last quote, so the whole line is quoted; and the
-  // arguments are passed VERBATIM, because Node otherwise backslash-escapes the
-  // quotes it sees and cmd.exe does not understand `\"` — every candidate then
-  // answers "exit 1", which reads as "no REA on this machine".
-  const result = platform === "win32" && /\.(cmd|bat)$/i.test(file)
-    ? spawnSync(comspec(), ["/d", "/s", "/c", `"${[cmdQuote(file), "--version"].join(" ")}"`], {
-        encoding: "utf8",
-        timeout,
-        windowsHide: true,
-        windowsVerbatimArguments: true,
-      })
-    : spawnSync(command[0], command.slice(1), {
-        encoding: "utf8",
-        timeout,
-        windowsHide: true,
-      });
-  if (result.error) {
-    // A timed-out probe leaves its grandchild running: cmd.exe is killed, the
-    // REA inside it is not, and it keeps the inherited pipes open. Clean the tree
-    // before answering, or a hung candidate leaves a process behind per start.
-    if (result.error.code === "ETIMEDOUT") killTree(result.pid, platform);
-    return { ok: false, reason: result.error.code === "ETIMEDOUT" ? "timeout" : "spawn-failed" };
-  }
-  if (result.status !== 0) return { ok: false, reason: `exit ${String(result.status)}` };
-  const text = `${result.stdout ?? ""}${result.stderr ?? ""}`.trim();
-  const version = /\b(\d+\.\d+\.\d+(?:-[0-9A-Za-z.-]+)?)\b/.exec(text)?.[1] ?? null;
-  // A REA install prints its version. Anything else (a shim that swallowed the
-  // flag, an unrelated program that shares the name) is not a usable CLI.
-  if (version === null) return { ok: false, reason: "no version in --version output" };
-  return { ok: true, version };
+  return new Promise((resolve) => {
+    // `existsSync` says nothing about the shape: a DIRECTORY named `rea.cmd`
+    // exists, fails to spawn, and would be reported as a broken install instead
+    // of as a name collision. Only a regular file is a candidate.
+    if (!isFileSync(file)) {
+      resolve({ ok: false, reason: "not a file" });
+      return;
+    }
+    const useShell = platform === "win32" && /\.(cmd|bat)$/i.test(file);
+    // `REA_BUNDLE_AUTO_PROVISION=0` is part of the same guard: if the candidate
+    // turns out to be a wrapper around THIS shim, the nested run must not start
+    // an 800 MB provisioning job just because a probe asked it for a version.
+    const env = { ...process.env, REA_BUNDLE_DELEGATED: "1", REA_BUNDLE_AUTO_PROVISION: "0" };
+    // `cmd /d /s /c "<line>"`: Windows only. Two details are load-bearing.
+    // `/s` strips the first and last quote, so the whole line is quoted; and the
+    // arguments are passed VERBATIM, because Node otherwise backslash-escapes the
+    // quotes it sees and cmd.exe does not understand `\"` — every candidate then
+    // answers "exit 1", which reads as "no REA on this machine".
+    const child = useShell
+      ? spawn(comspec(), ["/d", "/s", "/c", `"${[cmdQuote(file), "--version"].join(" ")}"`], {
+          env,
+          stdio: ["ignore", "pipe", "pipe"],
+          windowsHide: true,
+          windowsVerbatimArguments: true,
+        })
+      : spawn(file, ["--version"], { env, stdio: ["ignore", "pipe", "pipe"], windowsHide: true });
+    let output = "";
+    let settled = false;
+    let timer = null;
+    const finish = (result) => {
+      if (settled) return;
+      settled = true;
+      if (timer !== null) clearTimeout(timer);
+      resolve(result);
+    };
+    timer = setTimeout(() => {
+      killTree(child.pid, platform);
+      finish({ ok: false, reason: "timeout" });
+    }, timeout);
+    child.stdout.on("data", (chunk) => { output += String(chunk); });
+    child.stderr.on("data", (chunk) => { output += String(chunk); });
+    child.on("error", () => finish({ ok: false, reason: "spawn-failed" }));
+    child.on("close", (code) => {
+      if (code !== 0) {
+        finish({ ok: false, reason: `exit ${String(code)}` });
+        return;
+      }
+      // A REA install prints its version. Anything else (a shim that swallowed
+      // the flag, an unrelated program that shares the name) is not a usable CLI.
+      const version = /\b(\d+\.\d+\.\d+(?:-[0-9A-Za-z.-]+)?)\b/.exec(output.trim())?.[1] ?? null;
+      finish(version === null
+        ? { ok: false, reason: "no version in --version output" }
+        : { ok: true, version });
+    });
+  });
 }
 
 /**
@@ -580,7 +660,7 @@ function probeRea(file, { platform = process.platform, timeout = PROBE_TIMEOUT_M
  * provisioner installed is the `bundle` mode, and delegating to it would be a
  * loop through a path the bundle already covers.
  */
-function detectSystemRea({ env = process.env, platform = process.platform, root, pluginRoot = PLUGIN_ROOT } = {}) {
+async function detectSystemRea({ env = process.env, platform = process.platform, root, pluginRoot = PLUGIN_ROOT } = {}) {
   const rejected = [];
   let profiled = 0;
   const explicit = (env.REA_BUNDLE_SYSTEM_REA ?? "").trim();
@@ -609,7 +689,7 @@ function detectSystemRea({ env = process.env, platform = process.platform, root,
       continue;
     }
     profiled += 1;
-    const probe = probeRea(candidate, { platform });
+    const probe = await probeRea(candidate, { platform });
     if (probe.ok) return { found: true, file: candidate, version: probe.version };
     if (rejected.length < 8) rejected.push({ file: candidate, reason: probe.reason });
   }
@@ -624,7 +704,9 @@ function detectSystemRea({ env = process.env, platform = process.platform, root,
   if (explicitPath !== null && explicitRejection !== null) {
     reason = `REA_BUNDLE_SYSTEM_REA was rejected (${explicitRejection.reason}): ${explicitPath}`;
   } else if (explicitPath !== null && !isFileSync(explicitPath)) {
-    reason = `REA_BUNDLE_SYSTEM_REA does not exist: ${explicitPath}`;
+    reason = existsSync(explicitPath)
+      ? `REA_BUNDLE_SYSTEM_REA is not a file: ${explicitPath}`
+      : `REA_BUNDLE_SYSTEM_REA does not exist: ${explicitPath}`;
   } else {
     reason = profiled === 0 ? "no rea on PATH" : "no usable rea on PATH";
   }
@@ -657,10 +739,10 @@ function compareDotted(a, b) {
  * the one this bundle provisioned would silently take the tool count back
  * (6.4.0 ships 170 tools, 6.5.0 ships 207), so the newer of the two wins and
  * the older is only used when asked for by name. `bundle` and `system` are
- * honoured literally 鈥?`system` fails loudly rather than provisioning 800 MB
+ * honoured literally — `system` fails loudly rather than provisioning 800 MB
  * behind an operator who asked for their own REA.
  */
-function resolveLaunch({ root, bundleVersion = null, bundleProvisioned = false, env = process.env, platform = process.platform } = {}) {
+async function resolveLaunch({ root, bundleVersion = null, bundleProvisioned = false, env = process.env, platform = process.platform } = {}) {
   const preference = launchPreference(env);
   if (preference.value === "bundle") {
     return { preference: preference.value, invalid: preference.invalid, mode: "bundle", reason: "pinned by REA_BUNDLE_LAUNCH=bundle" };
@@ -678,7 +760,7 @@ function resolveLaunch({ root, bundleVersion = null, bundleProvisioned = false,
       reason: "REA_BUNDLE_DELEGATED=1: already running under a delegated system REA, refusing to delegate again",
     };
   }
-  const system = detectSystemRea({ env, platform, root });
+  const system = await detectSystemRea({ env, platform, root });
   if (system.found) {
     const order = bundleVersion === null ? null : compareDotted(system.version, bundleVersion);
     const pinned = preference.value === "system";
@@ -747,25 +829,14 @@ function launchSystemRea(system, argv) {
         windowsVerbatimArguments: true,
       })
     : spawn(system.file, args, { env, stdio: "inherit", windowsHide: true });
-  // Signal handling, per platform, because the two are not the same problem.
-  //
-  // POSIX: stdio is inherited and the child is in this process's group, so a
-  // terminal's Ctrl+C already reaches it. Forwarding again would deliver the
-  // signal twice.
-  //
-  // Windows: there is no process group to deliver to, and `child.kill("SIGINT")`
-  // is TerminateProcess on the cmd.exe WRAPPER — the REA inside it survives and
-  // keeps the inherited pipes open, which looks exactly like "the tools still
-  // work after I stopped the harness". `taskkill /T` is what actually ends the
-  // tree, so that is what a signal asks for here.
-  if (process.platform === "win32") {
-    for (const signal of ["SIGINT", "SIGTERM"]) {
-      process.on(signal, () => {
-        killTree(child.pid, "win32");
-        process.exit(signal === "SIGINT" ? 130 : 143);
-      });
-    }
-  }
+  // No signal forwarding on Windows, deliberately. `child.kill()` there is
+  // TerminateProcess on the cmd.exe WRAPPER — the REA inside it survives, still
+  // holding the inherited pipes — and a console Ctrl+C is delivered to the whole
+  // process group anyway, so the child already has it. A hard kill of this shim
+  // (what a supervisor or Task Manager does) runs no JavaScript at all, so the
+  // wrapper must not pretend otherwise: on Windows the delegated REA outlives a
+  // forcibly killed shim. On POSIX the child is in this process's group and gets
+  // the terminal's signal directly; `process.exit` below then ends the shim.
   child.on("error", (error) => {
     process.stderr.write(`rea-shim: could not start ${system.file}\n  ${String(error && error.message)}\n`);
     process.exit(EX_CONFIG);
@@ -780,11 +851,145 @@ function launchSystemRea(system, argv) {
   return null;
 }
 
+/**
+ * The mirror problem.
+ *
+ * The published row launches `<bundle>/bin/rea-shim.mjs` — a COPY made by
+ * `setup.mjs`. Upgrading the plugin from the market replaces the package but runs
+ * no setup, so the copy keeps executing the code it was made from: every fix in
+ * a new plugin version reaches a user only if they happen to re-run setup. That
+ * is invisible (the old copy keeps working) and it is exactly the wrong
+ * direction for a safety fix.
+ *
+ * The repair has to live in the copy, because the copy is what runs. So the
+ * copy compares itself with the plugin's own `bin/rea-shim.mjs`, recorded in
+ * `mirror.json` by setup, and re-execs that file when the two differ. One hop,
+ * guarded by an environment flag, and only from mirror to checkout — the
+ * checkout copy has no `mirror.json` and would find itself anyway.
+ *
+ * A plugin version older than 2.0.8 cannot do this for its own upgrades: there
+ * is nothing in it to run. `--shim-status` reports `mirror.stale` so the
+ * condition is at least visible, and `check-updates.ps1` says to re-run setup.
+ */
+function sha256(file) {
+  return createHash("sha256").update(readFileSync(file)).digest("hex");
+}
+
+/** Where the installed plugin lives according to setup's record, or null. */
+function pluginCheckout(root) {
+  try {
+    const record = readJson(path.join(root, "mirror.json"));
+    const dir = record?.pluginRoot;
+    if (typeof dir !== "string" || dir.trim() === "") return null;
+    const shim = path.join(dir, "bin", "rea-shim.mjs");
+    return isFileSync(shim) ? shim : null;
+  } catch {
+    return null;
+  }
+}
+
+/**
+ * Whether this copy is behind the plugin it was mirrored from.
+ *
+ * `self` is this file, `source` the checkout's. A checkout copy (it ships
+ * `cordis.patch.yml`) is never stale against itself; a mirror with no record, or
+ * whose recorded checkout is gone, is not re-pointed anywhere.
+ */
+function describeMirror(root, { self = fileURLToPath(import.meta.url) } = {}) {
+  let record = null;
+  try {
+    record = readJson(path.join(root, "mirror.json"));
+  } catch {
+    return null;
+  }
+  const source = pluginCheckout(root);
+  let stale = false;
+  let reason = "no usable plugin checkout in mirror.json";
+  if (source !== null) {
+    if (path.resolve(source) === path.resolve(self)) {
+      reason = "this copy is the plugin checkout";
+    } else {
+      try {
+        stale = sha256(source) !== sha256(self);
+        reason = stale ? "the plugin ships a different launcher than this mirrored copy" : "this copy matches the plugin";
+      } catch {
+        reason = "could not compare the two launchers";
+      }
+    }
+  }
+  return {
+    pluginRoot: typeof record?.pluginRoot === "string" ? record.pluginRoot : null,
+    mirroredAt: typeof record?.mirroredAt === "string" ? record.mirroredAt : null,
+    stale,
+    reason,
+  };
+}
+
+/**
+ * Run the checkout's launcher instead of this copy, once.
+ *
+ * The promise resolves ONLY when the re-exec did not take over, and the caller
+ * must then continue with its own launch path. While the child is alive the
+ * promise stays pending and the child's own exit becomes this process's exit —
+ * settling it at the `spawn` event was wrong: the event fires before the child
+ * has done anything, so a later "it actually failed" could no longer be seen, and
+ * the two handlers disagreed about who owns the exit code. That mistake made the
+ * file-vanishes-mid-flight case exit 0 silently.
+ *
+ * The first version of this printed "continuing with the mirrored copy" on
+ * `error` and returned: nothing continued, no `exit` event followed a failed
+ * spawn, the loop drained, and the row saw exit 0 with no tools and no message.
+ * A fallback that is announced but not performed is worse than none, because it
+ * hides the failure it was written for.
+ */
+function reexecFromCheckout(source, argv) {
+  const child = spawn(process.execPath, [source, ...argv], {
+    stdio: "inherit",
+    env: { ...process.env, REA_BUNDLE_SHIM_REEXEC: "1" },
+    windowsHide: true,
+  });
+  return new Promise((resolve) => {
+    let started = false;
+    child.once("spawn", () => {
+      started = true;
+    });
+    child.once("error", () => {
+      if (started) return;
+      resolve(false);
+    });
+    child.once("exit", (code, signal) => {
+      if (!started) {
+        // Exit without a spawn event: the child never ran. Let the caller fall
+        // back rather than exiting 0 on its behalf.
+        resolve(false);
+        return;
+      }
+      if (signal) {
+        const signals = { SIGHUP: 1, SIGINT: 2, SIGQUIT: 3, SIGKILL: 9, SIGTERM: 15 };
+        process.exit(128 + (signals[signal] ?? 0));
+      }
+      // A non-zero exit is normally the child's own answer and must be passed
+      // through untouched. One case is not the child's answer: an upgrade in
+      // flight replaced the file BETWEEN the check and node reading it, so node
+      // starts fine and dies with MODULE_NOT_FOUND. Passing that on turns a
+      // millisecond race into a dead row; if the source is gone by now, fall back
+      // to this copy instead. The window is small, the cost of covering it is one
+      // stat, and the alternative is a row that reports failure for a file that
+      // still exists a directory up.
+      if ((code ?? 0) !== 0 && !isFileSync(source)) {
+        resolve(false);
+        return;
+      }
+      process.exit(code ?? 0);
+    });
+  });
+}
+
 /**
  * Usage text, also what a bare invocation prints.
  *
  * `package.json` exposes this file as the `rea-bundle-status` bin, and npm's bin
- * shim can only forward the arguments a user typed 鈥?it cannot append a flag. So a
+ * shim can only forward the arguments a user typed — it cannot append a flag. So a
  * bare `rea-bundle-status`, which is exactly what that name invites, used to fall
  * through to the launch path: it started REA, and on an unprovisioned machine it
  * began an ~800 MB download. Reporting usage instead makes the command's behaviour
@@ -808,7 +1013,7 @@ function usage() {
   ].join("\n");
 }
 
-function main() {
+async function main() {
   const argv = process.argv.slice(2);
 
   if (argv.includes("--shim-help") || argv.length === 0) {
@@ -817,12 +1022,36 @@ function main() {
   }
 
   const root = bundleRoot();
+  // Self-healing before anything else: a mirrored copy that predates the plugin
+  // it was made from would otherwise keep running that older code forever, and a
+  // market upgrade never re-runs setup. One hop, guarded, and never for the
+  // status query — there the staleness is reported instead.
+  const mirror = describeMirror(root);
+  // A CHECKOUT copy is the source, not a mirror: hopping from it into whatever
+  // the bundle's record names would silently run a different plugin — a developer
+  // testing a local edit would be testing the installed one instead. The
+  // discriminator is the one bundleRoot() already uses: only the checkout ships
+  // cordis.patch.yml.
+  const isCheckout = existsSync(path.join(PLUGIN_ROOT, "cordis.patch.yml"));
+  if (!isCheckout && mirror !== null && mirror.stale && process.env.REA_BUNDLE_SHIM_REEXEC !== "1" && !argv.includes("--shim-status")) {
+    const source = pluginCheckout(root);
+    if (source !== null) {
+      // It resolves only when the re-exec did not take over; while the child
+      // runs, this process is parked and the child's exit is the exit.
+      await reexecFromCheckout(source, argv);
+      // The re-exec did not take over: a spawn failure, a child that exited
+      // before its spawn event, or one that started and found its own file gone
+      // (see the exit handler). Say so and run this copy for real — the point of
+      // the fallback.
+      process.stderr.write(`rea-shim: could not run ${source}; running the mirrored copy instead.\n`);
+    }
+  }
   const loaded = readBundleConfig(root);
   // Decide what to run before asking whether the bundle is provisioned: a
   // machine with its own working REA must not be sent into an ~800 MB
   // provisioning run just because this bundle has no state yet.
   const bundleVersion = loaded.ok ? (loaded.config.versions?.reaAgents ?? null) : null;
-  const launch = resolveLaunch({ root, bundleVersion, bundleProvisioned: loaded.ok });
+  const launch = await resolveLaunch({ root, bundleVersion, bundleProvisioned: loaded.ok });
   if (launch.invalid !== null) {
     process.stderr.write(
       `rea-shim: REA_BUNDLE_LAUNCH="${launch.invalid}" is not one of ${LAUNCH_MODES.join("/")}; using auto.\n`,
@@ -831,7 +1060,7 @@ function main() {
   // Upstream can add a second row for the same serverName; the shim cannot stop
   // DSH from loading both rows, but saying so is better than doubled tools with
   // no stated cause. The status report carries the same fact for diagnostics.
-  const duplicate = foreignReaRegistration();
+  const duplicate = foreignReaRegistration(root);
   if (duplicate && !argv.includes("--shim-status")) {
     process.stderr.write(
       `\n  dsh-plugin-rea (bundle): duplicate REA registration.\n` +
@@ -860,6 +1089,10 @@ function main() {
       },
     };
     if (launch.system?.rejected?.length) report.launch.rejected = launch.system.rejected;
+    // A mirrored copy that lags the plugin keeps working, which is exactly why
+    // nobody notices it: the row runs old code until the mirror is refreshed.
+    // Reported here so `--shim-status` answers "am I running what I installed?".
+    if (mirror !== null) report.mirror = mirror;
     if (duplicate) report.duplicateRegistration = duplicate;
     if (loaded.ok) {
       report.paths = loaded.config.paths ?? {};
@@ -909,12 +1142,12 @@ function main() {
     const provisioning = maybeAutoProvision(root);
     if (provisioning.started) {
       process.stderr.write(
-        `\n  dsh-plugin-rea (bundle): first run 鈥?provisioning started in the background.\n  progress: ${provisioning.logPath}\n`,
+        `\n  dsh-plugin-rea (bundle): first run — provisioning started in the background.\n  progress: ${provisioning.logPath}\n`,
       );
     } else if (provisioning.reason === "last-run-failed") {
       process.stderr.write(
         `\n  dsh-plugin-rea (bundle): the last provisioning attempt failed (exit ${provisioning.exit ?? "?"}).\n` +
-          `  Nothing is running right now 鈥?read the log, then re-run setup.\n  log: ${provisioning.logPath}\n`,
+          `  Nothing is running right now — read the log, then re-run setup.\n  log: ${provisioning.logPath}\n`,
       );
     } else if (provisioning.reason === "in-flight") {
       // A live run owns the lock. Saying nothing here is what made a wedged
@@ -972,5 +1205,8 @@ function main() {
   return null;
 }
 
-const status = main();
+// The launch decision awaits a probe, so `main` is async; the status it returns
+// is this process's exit code, and a launch path resolves to null while the
+// child (already wired to `process.exit`) keeps the loop alive.
+const status = await main();
 if (typeof status === "number") process.exit(status);

check-updates.ps1

@@ -73,9 +73,13 @@ function Test-NodeEngines([string]$node, [string]$engines) {
 # bundle.json：把全局路径当默认是 1.x 的答案，在 2.x 机器上会让这一节指向错误的
 # 对象（"全局包丢了"），并给出错误的升级动作（npm i -g）。
 $bundleRootEarly = $env:REA_BUNDLE_ROOT
+# Resolve the home unconditionally: the profile section below needs it whether or
+# not REA_BUNDLE_ROOT was set, and computing it only inside the fallback branch
+# left it $null — `Join-Path $null 'profiles'` throws, so the section degraded to
+# "no profile" on exactly the machines that use the override.
+$homeEarly = $env:DSH_HOME
+if (-not $homeEarly) { $homeEarly = Join-Path $HOME '.dsh' }
 if (-not $bundleRootEarly) {
-  $homeEarly = $env:DSH_HOME
-  if (-not $homeEarly) { $homeEarly = Join-Path $HOME '.dsh' }
   $bundleRootEarly = Join-Path $homeEarly 'plugins\rea-bundle'
 }
 $bundleState = $null
@@ -106,8 +110,12 @@ $reaFromBundle = [bool]($bundleReaPackageDir -and $ReaPackageDir -eq $bundleReaP
 if (-not $ProfileDir) {
   if ($env:DSH_PROFILE_DIR) { $ProfileDir = $env:DSH_PROFILE_DIR }
   else {
-    $profiles = @(Get-ChildItem (Join-Path $env:USERPROFILE '.dsh\profiles') -Directory -ErrorAction SilentlyContinue)
-    $ProfileDir = if ($profiles.Count -gt 0) { $profiles[0].FullName } else { Join-Path $env:USERPROFILE '.dsh\profiles\desktop' }
+    # Same home rule the bundle uses everywhere else: DSH_HOME, then ~/.dsh.
+    # Hardcoding $env:USERPROFILE here was a second algorithm in the same script,
+    # so on a custom DSH_HOME the profile section reported "no profile found"
+    # while the rest of the run had already resolved that home correctly.
+    $profiles = @(Get-ChildItem (Join-Path $homeEarly 'profiles') -Directory -ErrorAction SilentlyContinue)
+    $ProfileDir = if ($profiles.Count -gt 0) { $profiles[0].FullName } else { Join-Path $homeEarly 'profiles\desktop' }
   }
 }
 
@@ -340,7 +348,27 @@ if (-not (Test-Path $manifestPath)) {
         Warn ("TOFU（无厂商校验和，取首次实测值）: " + (@($state.unverifiedChecksums) -join ', '))
       }
       $mirrored = Join-Path $bundleRoot 'bin\rea-shim.mjs'
-      if (Test-Path $mirrored) { Ok 'MCP 行指向的 shim 已就位' }
+      if (Test-Path $mirrored) {
+        Ok 'MCP 行指向的 shim 已就位'
+        # The row launches this COPY, so a plugin upgrade that does not re-run
+        # setup leaves the old launcher in place — visible only as "the new
+        # version behaves like the old one". Compare it with the checkout the
+        # mirror record names.
+        $mirrorRecord = Join-Path $bundleRoot 'mirror.json'
+        if (Test-Path $mirrorRecord) {
+          try {
+            $record = Get-Content $mirrorRecord -Raw -Encoding UTF8 | ConvertFrom-Json
+            $pluginShim = if ($record.pluginRoot) { Join-Path $record.pluginRoot 'bin\rea-shim.mjs' } else { $null }
+            if ($pluginShim -and (Test-Path $pluginShim)) {
+              $same = (Get-FileHash $mirrored -Algorithm SHA256).Hash -eq (Get-FileHash $pluginShim -Algorithm SHA256).Hash
+              if ($same) { Ok '镜像 shim 与插件一致（行跑的就是这个版本）' }
+              else { Warn "镜像 shim 落后于插件（$($record.pluginRoot)）—— 行仍在跑旧副本；重跑 node scripts/setup.mjs 让它换成新版本" }
+            } else {
+              Warn "mirror.json 指向的插件目录已不存在（$($record.pluginRoot)）—— 无法比对镜像 shim 是否最新"
+            }
+          } catch { Warn "mirror.json 解析失败: $($_.Exception.Message)" }
+        }
+      }
       else { Bad "缺少 MCP 行指向的 shim: $mirrored —— 重跑 setup --reuse" }
       # 镜像副本的 setup 用它自己所在的位置推 plugin root，所以 manifest 必须
       # 一起镜像。旧版镜像缺这个文件：auto-provision 会以 ENOENT 崩掉且不可见，

docs/bundle-design.md

@@ -83,7 +83,10 @@ through `failOnStartupError: false` without breaking the harness.
 ```
 dsh starts
   └─ MCP row: node <bundle root>/bin/rea-shim.mjs   (setup mirrors it there)
-       ├─ bundle.json present & components verify  → exec REA (normal path)
+       ├─ mirrored copy differs from the installed plugin → re-exec that copy, once
+       ├─ a working `rea` on PATH is at least as new as the bundle
+       │                                            → exec it (the 1.x contract)
+       ├─ bundle.json present & components verify  → exec the provisioned REA
        ├─ missing, auto-provision allowed         → start setup detached, print
        │                                            remediation, exit non-zero
        └─ missing, auto-provision refused         → print exact command, exit
@@ -129,6 +132,26 @@ Two notes on stages that exist because their absence was a bug:
   harness's own dialect, `args[0]` became `{"[object Object]": "..."}` and the
   row could not launch at all. Any future expression with a ternary needs the
   quotes; `audit-manifest.mjs` rejects the bare form.
+- **Launch mode (2.0.7).** 2.x exists to supply a runtime a machine lacks, so a
+  machine that already has one should not be provisioned. Before touching bundle
+  state the shim asks whether `rea` is on PATH and answers `--version`; if it
+  does, and its version is not older than `bundle.json`'s `versions.reaAgents`,
+  the row execs that install exactly as the 1.x row did. The probe is asynchronous
+  and bounded (8 s: a `.cmd` shim needs ~2.4 s), runs with
+  `REA_BUNDLE_DELEGATED=1` and `REA_BUNDLE_AUTO_PROVISION=0` so a candidate that
+  wraps this shim cannot recurse or start an 800 MB run, and kills its whole tree
+  on timeout. `REA_BUNDLE_LAUNCH=auto|system|bundle` overrides the choice; an
+  unorderable pair (a prerelease on either side) keeps the bundle.
+- **Self-healing mirror (2.0.8).** The row launches a COPY, and a market upgrade
+  runs no setup, so without this the copy keeps executing the code it was made
+  from — invisibly, because it still works. The copy therefore compares its own
+  hash with `<mirror.json.pluginRoot>/bin/rea-shim.mjs` and re-execs that file
+  when they differ: one hop, guarded by `REA_BUNDLE_SHIM_REEXEC`, and only from a
+  mirror (a checkout ships `cordis.patch.yml`, so it never hops into another
+  copy). `mirror.json` carries `shimSha256`, `pluginVersion` and `dshHome` —
+  the last one because the harness strips `DSH_*` from an MCP child, so the
+  duplicate-registration check would otherwise read `~/.dsh` on a machine with a
+  custom home. `--shim-status` reports `mirror.stale` instead of hopping.
 - **3 (fetch).** Route order is deliberate and environment-dependent: direct
   first, then the system proxy, and on Windows the .NET route ahead of both
   because it follows the GitHub release-asset redirect that the Node routes

package.json

@@ -1,6 +1,6 @@
 {
   "name": "dsh-plugin-rea",
-  "version": "2.0.7",
+  "version": "2.0.9",
   "description": "One-plugin bundle: provisions Node/REA/JDK/Ghidra for you, then registers the upstream REA MCP server as mcp__rea__* tools. · 一体包：自动准备 Node/REA/JDK/Ghidra，并把上游 REA 的 MCP 服务接入 DeepSeek Harness。",
   "type": "module",
   "main": "./index.mjs",

scripts/setup.mjs

@@ -954,6 +954,21 @@ function reuseExisting(name, root) {
 
 /* ------------------------------------------------------------------- manifest */
 
+/**
+ * JSON from disk, tolerating the UTF-8 BOM a Windows editor writes.
+ *
+ * `JSON.parse` rejects a leading BOM, and every caller in this file treats a
+ * parse failure as "no record". A BOM-ed mirror.json therefore meant "this is
+ * not a mirrored run", so setup went on to re-mirror the previous manifest;
+ * a BOM-ed bundle.json meant "nothing is provisioned". `bin/rea-shim.mjs`
+ * carries the same helper — the two must agree, or the same file means two
+ * different things depending on which one read it (a hand-edited record with
+ * PowerShell's BOM is exactly the case that produced this).
+ */
+function readJson(file) {
+  return JSON.parse(readFileSync(file, "utf8").replace(/^\uFEFF/, ""));
+}
+
 /**
  * Where this run's plugin files actually live.
  *
@@ -973,7 +988,7 @@ function sourceRoot() {
   const self = path.resolve(PLUGIN_ROOT);
   if (!samePath(self, options.root)) return self;
   try {
-    const record = JSON.parse(readFileSync(path.join(options.root, "mirror.json"), "utf8"));
+    const record = readJson(path.join(options.root, "mirror.json"));
     const recorded = record?.pluginRoot;
     if (typeof recorded === "string" && recorded.trim() !== "") {
       const candidate = path.resolve(recorded);
@@ -987,7 +1002,7 @@ function sourceRoot() {
 
 function loadManifest() {
   const file = path.join(sourceRoot(), "manifest", "bundle.manifest.json");
-  const parsed = JSON.parse(readFileSync(file, "utf8"));
+  const parsed = readJson(file);
   return parsed;
 }
 
@@ -1002,7 +1017,7 @@ function loadManifest() {
 function readBundleJson(file) {
   if (!existsSync(file)) return null;
   try {
-    const parsed = JSON.parse(readFileSync(file, "utf8"));
+    const parsed = readJson(file);
     return parsed && typeof parsed === "object" && !Array.isArray(parsed) ? parsed : null;
   } catch (error) {
     log(`       ${path.basename(file)} is not readable JSON (${String(error && error.message)}); ignoring it for this run`);
@@ -1636,6 +1651,31 @@ function mirrorLauncher(context) {
  */
 function writeMirrorRecord(context, source) {
   const record = { schema: 1, pluginRoot: source, mirroredAt: new Date().toISOString() };
+  // Provenance for the self-healing check: the mirrored shim compares itself
+  // with `<pluginRoot>/bin/rea-shim.mjs` and re-execs that one when the plugin
+  // has moved on. These two fields are what `--shim-status` shows when the
+  // comparison cannot be made (missing checkout, unreadable file).
+  try {
+    record.shimSha256 = createHash("sha256")
+      .update(readFileSync(path.join(context.root, "bin", "rea-shim.mjs")))
+      .digest("hex");
+  } catch {
+    /* the copy is missing or unreadable; the shim reports the comparison itself */
+  }
+  try {
+    record.pluginVersion = readJson(path.join(source, "package.json")).version ?? null;
+  } catch {
+    record.pluginVersion = null;
+  }
+  // The MCP child the harness starts has every DSH_* variable stripped, so the
+  // mirrored shim cannot re-derive a CUSTOM home from its environment — it would
+  // read `~/.dsh` and miss a duplicate `serverName: rea` living in the real one.
+  // Record the home setup ran under; the shim prefers the environment, then this.
+  try {
+    record.dshHome = dshHome();
+  } catch {
+    record.dshHome = null;
+  }
   try {
     mkdirSync(context.root, { recursive: true });
     writeFileSync(path.join(context.root, "mirror.json"), JSON.stringify(record, null, 2) + "\n");

scripts/setup.test.mjs

@@ -1313,13 +1313,13 @@ function writeFakeRea(dir, { version = "6.9.0", exitForVersion = 0, runExit = 0,
   return file;
 }
 
-function runShimIsolated(env, args) {
+function runShimIsolated(env, args, shim = path.join(REPO_ROOT, "bin", "rea-shim.mjs")) {
   const merged = { ...process.env, ...env };
   // Windows keeps PATH and Path as separate variables (both are "in" the
   // environment), and a child that reads Path while the test set PATH would see
   // the machine's real search path instead of the fixture's.
   if (process.platform === "win32" && Object.prototype.hasOwnProperty.call(env, "PATH")) delete merged.Path;
-  return spawnSync(process.execPath, [path.join(REPO_ROOT, "bin", "rea-shim.mjs"), ...args], {
+  return spawnSync(process.execPath, [shim, ...args], {
     encoding: "utf8",
     timeout: 60000,
     env: merged,
@@ -1564,3 +1564,328 @@ test("--shim-print-env reports the system launch instead of a child environment"
     f.clean();
   }
 });
+
+test("a candidate that wraps this shim is rejected instead of recursing", () => {
+  // The probe asks the candidate for `--version`; a wrapper answers by running
+  // this very shim, which would probe the wrapper again. The probe therefore runs
+  // with REA_BUNDLE_DELEGATED=1, so the nested run takes the bundle path and
+  // returns. Without that, one wrapper on PATH spawns a process chain that keeps
+  // respawning after the parent is killed.
+  const f = launchFixture();
+  mkdirSync(f.bin, { recursive: true });
+  const shim = path.join(REPO_ROOT, "bin", "rea-shim.mjs");
+  const wrapper = path.join(f.bin, process.platform === "win32" ? "rea.cmd" : "rea");
+  if (process.platform === "win32") {
+    writeFileSync(wrapper, `@echo off\r\n"${process.execPath}" "${shim}" %*\r\n`);
+  } else {
+    writeFileSync(wrapper, `#!/bin/sh\nexec "${process.execPath}" "${shim}" "$@"\n`);
+    chmodSync(wrapper, 0o755);
+  }
+  try {
+    const started = Date.now();
+    const run = runShimIsolated(
+      { PATH: f.emptyPath, REA_BUNDLE_SYSTEM_REA: wrapper, REA_BUNDLE_ROOT: f.bundleRoot, REA_BUNDLE_AUTO_PROVISION: "0", REA_BUNDLE_LAUNCH: "" },
+      ["--shim-status"],
+    );
+    const elapsed = Date.now() - started;
+    const report = JSON.parse(run.stdout);
+    assert.equal(report.launch.mode, "bundle");
+    assert.deepEqual(report.launch.rejected.map(r => r.reason), ["exit 78"]);
+    assert.ok(elapsed < 20000, `the probe must not recurse; it took ${elapsed} ms`);
+  } finally {
+    f.clean();
+  }
+});
+
+test("a ComSpec that points at nothing falls back to the real shell", () => {
+  // Trusting ComSpec blindly would judge every .cmd REA "spawn-failed" — i.e.
+  // report the machine as having no REA because its shell pointer is broken.
+  const f = launchFixture();
+  mkdirSync(f.bin, { recursive: true });
+  const rea = writeFakeRea(f.bin, { version: "6.9.0" });
+  try {
+    const run = runShimIsolated(
+      {
+        PATH: f.emptyPath,
+        ComSpec: path.join(f.root, "no-such-cmd.exe"),
+        REA_BUNDLE_SYSTEM_REA: rea,
+        REA_BUNDLE_ROOT: f.bundleRoot,
+        REA_BUNDLE_AUTO_PROVISION: "0",
+        REA_BUNDLE_LAUNCH: "",
+      },
+      ["--shim-status"],
+    );
+    const report = JSON.parse(run.stdout);
+    if (process.platform === "win32") {
+      assert.equal(report.launch.mode, "system", JSON.stringify(report.launch));
+      assert.equal(report.launch.systemRea.version, "6.9.0");
+    } else {
+      // POSIX never consults ComSpec; the assertion above would be incidental.
+      assert.equal(report.launch.mode, "system");
+    }
+  } finally {
+    f.clean();
+  }
+});
+
+/* --------------------------------------------------- the mirrored launcher */
+
+// The row launches `<bundle>/bin/rea-shim.mjs`, a COPY. A market upgrade replaces
+// the package and runs no setup, so without this the copy keeps running the code
+// it was made from — every fix silently stops at the old mirror. These tests pin
+// the repair: the copy re-execs the plugin's launcher when they differ, once.
+
+function mirrorFixture() {
+  const root = mkdtempSync(path.join(tmpdir(), "rea-mirror-"));
+  const bundle = path.join(root, "bundle");
+  const checkout = path.join(root, "checkout");
+  mkdirSync(path.join(bundle, "bin"), { recursive: true });
+  mkdirSync(path.join(checkout, "bin"), { recursive: true });
+  copyFileSync(path.join(REPO_ROOT, "bin", "rea-shim.mjs"), path.join(bundle, "bin", "rea-shim.mjs"));
+  writeFileSync(path.join(bundle, "mirror.json"), JSON.stringify({ schema: 1, pluginRoot: checkout, mirroredAt: "2026-10-18T00:00:00Z" }));
+  return { root, bundle, checkout, clean() { rmSync(root, { recursive: true, force: true }); } };
+}
+
+function checkoutStub(checkout, marker) {
+  const file = path.join(checkout, "bin", "rea-shim.mjs");
+  writeFileSync(
+    file,
+    'import { writeFileSync } from "node:fs";\n' +
+      `writeFileSync(${JSON.stringify(marker)}, "checkout");\n` +
+      "process.exit(7);\n",
+  );
+  return file;
+}
+
+test("a mirrored launcher re-execs the plugin's launcher when they differ", () => {
+  const f = mirrorFixture();
+  const marker = path.join(f.root, "checkout-ran");
+  checkoutStub(f.checkout, marker);
+  try {
+    // The mirrored copy is what the row launches, and the checkout guard means a
+    // checkout shim refuses to hop at all — so the fixture must be exercised as
+    // the mirror it is meant to be.
+    const run = runShimIsolated(
+      { REA_BUNDLE_ROOT: f.bundle, REA_BUNDLE_AUTO_PROVISION: "0", REA_BUNDLE_LAUNCH: "bundle" },
+      ["mcp"],
+      path.join(f.bundle, "bin", "rea-shim.mjs"),
+    );
+    assert.equal(run.status, 7, `expected the checkout's status, got ${run.status}: ${run.stderr}`);
+    assert.equal(existsSync(marker), true, "the checkout launcher must have run");
+  } finally {
+    f.clean();
+  }
+});
+
+test("the re-exec happens once, and a pinned guard stops it", () => {
+  const f = mirrorFixture();
+  const marker = path.join(f.root, "checkout-ran");
+  checkoutStub(f.checkout, marker);
+  try {
+    const run = runShimIsolated(
+      { REA_BUNDLE_ROOT: f.bundle, REA_BUNDLE_AUTO_PROVISION: "0", REA_BUNDLE_LAUNCH: "bundle", REA_BUNDLE_SHIM_REEXEC: "1" },
+      ["mcp"],
+      path.join(f.bundle, "bin", "rea-shim.mjs"),
+    );
+    // The guard is set, so the mirrored copy runs its own logic: bundle pinned and
+    // nothing provisioned means EX_CONFIG, and the checkout never starts.
+    assert.equal(run.status, 78, run.stderr);
+    assert.equal(existsSync(marker), false, "the guard must prevent a second hop");
+  } finally {
+    f.clean();
+  }
+});
+
+test("--shim-status reports a stale mirror instead of re-execing it", () => {
+  const f = mirrorFixture();
+  const marker = path.join(f.root, "checkout-ran");
+  checkoutStub(f.checkout, marker);
+  try {
+    const run = runShimIsolated(
+      { REA_BUNDLE_ROOT: f.bundle, REA_BUNDLE_AUTO_PROVISION: "0", REA_BUNDLE_LAUNCH: "bundle" },
+      ["--shim-status"],
+      path.join(f.bundle, "bin", "rea-shim.mjs"),
+    );
+    const report = JSON.parse(run.stdout);
+    assert.equal(report.mirror.stale, true, JSON.stringify(report.mirror));
+    assert.match(report.mirror.reason, /different launcher/);
+    assert.equal(existsSync(marker), false, "status is a query; it must not start anything");
+  } finally {
+    f.clean();
+  }
+});
+
+test("a checkout shim does not hop into the installed plugin", () => {
+  const f = mirrorFixture();
+  const marker = path.join(f.root, "checkout-ran");
+  checkoutStub(f.checkout, marker);
+  try {
+    // The repository's own shim is a CHECKOUT (it ships cordis.patch.yml). A
+    // developer running it must keep testing the edit in front of them, not a
+    // different plugin that the bundle's record happens to name.
+    const run = runShimIsolated(
+      { REA_BUNDLE_ROOT: f.bundle, REA_BUNDLE_AUTO_PROVISION: "0", REA_BUNDLE_LAUNCH: "bundle" },
+      ["mcp"],
+    );
+    assert.equal(run.status, 78, run.stderr);
+    assert.equal(existsSync(marker), false, "a checkout must never hop into another copy");
+  } finally {
+    f.clean();
+  }
+});
+
+test("a re-exec whose file vanishes mid-flight falls back to the mirrored copy", () => {
+  // The upgrade race the spawn handshake cannot see: the file existed when the
+  // mirror compared hashes, node started, and the file was replaced before node
+  // read it — node exits 1 with MODULE_NOT_FOUND. Passing that through turns a
+  // millisecond race into a dead row, so a non-zero exit with the source gone
+  // must fall back instead.
+  const f = mirrorFixture();
+  const marker = path.join(f.root, "checkout-ran");
+  const file = path.join(f.checkout, "bin", "rea-shim.mjs");
+  writeFileSync(
+    file,
+    'import { rmSync, writeFileSync } from "node:fs";\n' +
+      `writeFileSync(${JSON.stringify(marker)}, "checkout");\n` +
+      `rmSync(${JSON.stringify(file)});\n` +
+      "process.exit(3);\n",
+  );
+  try {
+    const run = runShimIsolated(
+      { REA_BUNDLE_ROOT: f.bundle, REA_BUNDLE_AUTO_PROVISION: "0", REA_BUNDLE_LAUNCH: "bundle" },
+      ["mcp"],
+      path.join(f.bundle, "bin", "rea-shim.mjs"),
+    );
+    assert.equal(existsSync(marker), true, "the checkout launcher did run");
+    assert.equal(run.status, 78, `expected the local copy's status, got ${run.status}: ${run.stderr}`);
+    assert.match(run.stderr, /running the mirrored copy instead/);
+  } finally {
+    f.clean();
+  }
+});
+
+test("an identical mirror is not stale and is not re-exec'd", () => {
+  const f = mirrorFixture();
+  const same = path.join(f.checkout, "bin", "rea-shim.mjs");
+  copyFileSync(path.join(f.bundle, "bin", "rea-shim.mjs"), same);
+  try {
+    const run = runShimIsolated(
+      { REA_BUNDLE_ROOT: f.bundle, REA_BUNDLE_AUTO_PROVISION: "0", REA_BUNDLE_LAUNCH: "bundle" },
+      ["--shim-status"],
+      path.join(f.bundle, "bin", "rea-shim.mjs"),
+    );
+    const report = JSON.parse(run.stdout);
+    assert.equal(report.mirror.stale, false, JSON.stringify(report.mirror));
+    assert.equal(report.mirror.reason, "this copy matches the plugin");
+  } finally {
+    f.clean();
+  }
+});
+
+test("a mirrored shim finds the real DSH home when the environment is scrubbed", () => {
+  // The harness strips DSH_* from an MCP child, so with a custom DSH_HOME the
+  // old code read ~/.dsh — the wrong file — and could never report upstream's
+  // duplicate `serverName: rea`. setup records the home; the shim must use it.
+  const f = mirrorFixture();
+  const home = path.join(f.root, "custom-home");
+  mkdirSync(home, { recursive: true });
+  writeFileSync(
+    path.join(home, "cordis.patch.yml"),
+    "- insert:\n    - id: rea-mcp\n      name: '@deepseek-ai/dsh-mcp-client'\n      config:\n        serverName: rea\n",
+  );
+  writeFileSync(
+    path.join(f.bundle, "mirror.json"),
+    JSON.stringify({ schema: 1, pluginRoot: f.checkout, mirroredAt: "2026-10-18T00:00:00Z", dshHome: home }),
+  );
+  try {
+    const run = runShimIsolated(
+      // DSH_HOME="" models the scrubbed environment: the variable exists, empty.
+      { REA_BUNDLE_ROOT: f.bundle, REA_BUNDLE_AUTO_PROVISION: "0", REA_BUNDLE_LAUNCH: "bundle", DSH_HOME: "" },
+      ["--shim-status"],
+    );
+    const report = JSON.parse(run.stdout);
+    assert.equal(report.duplicateRegistration?.id, "rea-mcp", run.stdout);
+    assert.equal(report.duplicateRegistration.patch, path.join(home, "cordis.patch.yml"));
+  } finally {
+    f.clean();
+  }
+});
+
+/* ------------------------------------ records a Windows editor has BOM-ed */
+
+// `bin/rea-shim.mjs` strips the UTF-8 BOM that PowerShell and Notepad write;
+// setup.mjs kept parsing raw. Both programs read the same two records, so a BOM
+// used to mean two different things: the shim found the checkout, setup did not.
+// A mirrored setup then re-mirrored the previous manifest and provisioned from
+// it, and a BOM-ed bundle.json read as "nothing is provisioned". These tests pin
+// setup's side of the contract, both files.
+
+/** A checkout with a manifest whose node probe accepts any node, so `--only node` is deterministic. */
+function bomFixtureCheckout(root) {
+  const checkout = path.join(root, "checkout");
+  mkdirSync(path.join(checkout, "scripts"), { recursive: true });
+  mkdirSync(path.join(checkout, "manifest"), { recursive: true });
+  copyFileSync(SETUP_SOURCE, path.join(checkout, "scripts", "setup.mjs"));
+  const manifest = JSON.parse(readFileSync(MANIFEST_SOURCE, "utf8"));
+  manifest.components.node.probe.expect.regex = "^v";
+  writeFileSync(path.join(checkout, "manifest", "bundle.manifest.json"), JSON.stringify(manifest, null, 2));
+  writeFileSync(path.join(checkout, "package.json"), JSON.stringify({ name: "dsh-plugin-rea", version: "0.0.0-bom" }));
+  return checkout;
+}
+
+test("a BOM-ed mirror.json still points a mirrored setup at the real checkout", () => {
+  const root = mkdtempSync(path.join(tmpdir(), "rea-bom-mirror-"));
+  try {
+    const checkout = bomFixtureCheckout(root);
+    const bundle = path.join(root, "bundle");
+    mkdirSync(path.join(bundle, "scripts"), { recursive: true });
+    copyFileSync(SETUP_SOURCE, path.join(bundle, "scripts", "setup.mjs"));
+    // Exactly what `Out-File` / `Set-Content` leaves behind, and what a human
+    // editing the record by hand produces on Windows.
+    writeFileSync(
+      path.join(bundle, "mirror.json"),
+      "\uFEFF" + JSON.stringify({ schema: 1, pluginRoot: checkout, mirroredAt: "2026-10-18T00:00:00Z" }),
+    );
+    // The bundle has no manifest of its own: only the record can supply one.
+    assert.equal(existsSync(path.join(bundle, "manifest", "bundle.manifest.json")), false);
+
+    const run = spawnSync(
+      process.execPath,
+      [path.join(bundle, "scripts", "setup.mjs"), "--dry-run", "--only", "node", "--root", bundle],
+      { encoding: "utf8", timeout: 120000 },
+    );
+    assert.equal(run.status, 0, run.stderr);
+    // loadManifest() runs before any component: reaching the plan proves the
+    // record was parsed. A BOM-blind parse fell through to the bundle and died
+    // on a missing manifest.
+    assert.match(run.stdout, /\[plan\] node/);
+  } finally {
+    rmSync(root, { recursive: true, force: true });
+  }
+});
+
+test("a BOM-ed bundle.json is read instead of treated as unprovisioned", () => {
+  const root = mkdtempSync(path.join(tmpdir(), "rea-bom-bundle-"));
+  try {
+    const checkout = bomFixtureCheckout(root);
+    const bundle = path.join(root, "bundle");
+    mkdirSync(bundle, { recursive: true });
+    const args = [path.join(checkout, "scripts", "setup.mjs"), "--dry-run", "--only", "node", "--root", bundle];
+
+    // Control: with no record at all the component is planned, so the assertion
+    // below cannot pass for a reason unrelated to reading the file.
+    const fresh = spawnSync(process.execPath, args, { encoding: "utf8", timeout: 120000 });
+    assert.equal(fresh.status, 0, fresh.stderr);
+    assert.match(fresh.stdout, /\[plan\] node/);
+
+    writeFileSync(
+      path.join(bundle, "bundle.json"),
+      "\uFEFF" + JSON.stringify({ schema: 1, components: { node: { path: process.execPath, version: "v-bom-test" } } }, null, 2),
+    );
+    const run = spawnSync(process.execPath, args, { encoding: "utf8", timeout: 120000 });
+    assert.equal(run.status, 0, run.stderr);
+    assert.match(run.stdout, /already provisioned \(v-bom-test\)/, run.stdout);
+  } finally {
+    rmSync(root, { recursive: true, force: true });
+  }
+});

scripts/verify-branch.ps1

@@ -17,6 +17,31 @@ foreach ($f in @('index.mjs','bin\rea-shim.mjs','scripts\setup.mjs','scripts\aud
   Check $f ($LASTEXITCODE -eq 0) ($out -join ' ')
 }
 
+Write-Host "`n=== 1b. both JSON readers tolerate a BOM ===" -ForegroundColor Cyan
+# bin/rea-shim.mjs and scripts/setup.mjs read the same mirror.json and bundle.json.
+# A BOM strip on one side only makes one file mean "there is a checkout" to the
+# shim and "there is none" to setup, and the mirrored setup then re-mirrors the
+# previous manifest. A bare JSON.parse(readFileSync(...)) is that divergence.
+$jsBom = Join-Path $env:TEMP 'rea-verify-bom.cjs'
+@'
+const fs = require("node:fs");
+const blind = [];
+for (const file of ["bin/rea-shim.mjs", "scripts/setup.mjs"]) {
+  const text = fs.readFileSync(file, "utf8");
+  for (const m of text.matchAll(/JSON\.parse\(\s*readFileSync\(/g)) {
+    // readJson() itself is the strip; anything else must not parse a file raw.
+    if (!/replace\(/.test(text.slice(m.index, m.index + 200))) {
+      blind.push(file + "@" + text.slice(0, m.index).split("\n").length);
+    }
+  }
+  if (!text.includes("replace(/^\\uFEFF/")) blind.push(file + ": no U+FEFF strip");
+}
+console.log("bom-blind reads: " + JSON.stringify(blind));
+if (blind.length) process.exit(1);
+'@ | Set-Content $jsBom -Encoding utf8
+& node $jsBom 2>&1 | ForEach-Object { Write-Host "        $_" -ForegroundColor Gray }
+Check 'no BOM-blind JSON read' ($LASTEXITCODE -eq 0) 'see above'
+
 Write-Host "`n=== 2. PowerShell parse + BOM ===" -ForegroundColor Cyan
 # This script checks itself too: it is edited as often as the others, and an editor
 # that drops the BOM would otherwise go unnoticed until someone adds CJK text here.
@@ -90,6 +115,19 @@ Check 'main resolves to a shipped file' ($pkg.main -and (Test-Path (Join-Path $r
 Check 'package.json declares engines.dsh' (-not [string]::IsNullOrWhiteSpace($pkg.engines.dsh)) ''
 $compat = & node scripts\host-compat.mjs 2>&1
 Check 'engines.dsh covers every released DSH host' ($LASTEXITCODE -eq 0) (($compat | Select-Object -Last 2) -join ' ')
+# Both READMEs quote the range verbatim, and a stale quote is invisible: JSON,
+# host-compat and the audit all agree while the sentence a human reads names a
+# different ceiling. That is exactly how `<0.3.0` survived in the docs after the
+# declaration moved to `<0.3.0-0`, so the comparison lives here now.
+foreach ($doc in @('README.md', 'README.zh-CN.md')) {
+  $text = Get-Content (Join-Path $root $doc) -Raw -Encoding UTF8
+  Check "$doc quotes the declared engines.dsh" $text.Contains([string]$pkg.engines.dsh) "expected $($pkg.engines.dsh)"
+  # The pin example is copy-pasteable, so it must name a ref that will exist: the
+  # version this tree publishes. It has drifted twice (v2.0.0 long after 2.0.5,
+  # then v2.0.8 while the tree was 2.0.9), and both times every other signal was
+  # green because nothing compared the two.
+  Check "$doc pins the current version" $text.Contains("dsh-plugin-rea#v$($pkg.version)") "expected dsh-plugin-rea#v$($pkg.version)"
+}
 foreach ($script in @('bundle:setup', 'bundle:status', 'bundle:audit', 'bundle:test', 'bundle:host-compat')) {
   Check "scripts.$script exists" ($pkg.scripts.PSObject.Properties.Name -contains $script) ''
 }