fix(core): tighten plan switch reminder copy

Rewrite enter and leave synthetics to state the read-only constraint
and its removal without extra workflow instructions.

packages/app/src/context/server-session-v2-reducer.test.ts

@@ -69,6 +69,63 @@ describe("v2 session reducer", () => {
     })
   })
 
+  test("prefers durable selection predecessors and derives them for older events", () => {
+    const source: SessionMessageInfo[] = [
+      { id: "msg_previous_agent", type: "agent-switched", agent: "build", time: { created: 1 } },
+      {
+        id: "msg_previous_model",
+        type: "model-switched",
+        model: { id: "old", providerID: "provider" },
+        time: { created: 1 },
+      },
+    ]
+    const reducer = createV2SessionReducer()
+
+    const agent = reducer.reduce(
+      source,
+      event({
+        ...base,
+        id: "evt_agent",
+        type: "session.agent.selected",
+        data: { sessionID: "ses_1", agent: "plan", previous: "review" },
+      }),
+    )
+    const model = reducer.reduce(
+      source,
+      event({
+        ...base,
+        id: "evt_model",
+        type: "session.model.selected",
+        data: {
+          sessionID: "ses_1",
+          model: { id: "new", providerID: "provider" },
+          previous: { id: "durable", providerID: "provider" },
+        },
+      }),
+    )
+    const legacyAgent = reducer.reduce(
+      source,
+      event({
+        ...base,
+        id: "evt_legacy_agent",
+        type: "session.agent.selected",
+        data: { sessionID: "ses_1", agent: "plan" },
+      }),
+    )
+
+    expect(agent?.messages.at(-1)).toMatchObject({ type: "agent-switched", agent: "plan", previous: "review" })
+    expect(model?.messages.at(-1)).toMatchObject({
+      type: "model-switched",
+      model: { id: "new" },
+      previous: { id: "durable" },
+    })
+    expect(legacyAgent?.messages.at(-1)).toMatchObject({
+      type: "agent-switched",
+      agent: "plan",
+      previous: "build",
+    })
+  })
+
   test("folds tool, retry, and completion events", () => {
     const reducer = createV2SessionReducer()
     let messages: SessionMessageInfo[] = []

packages/app/src/context/server-session-v2-reducer.ts

@@ -61,6 +61,12 @@ export function createV2SessionReducer() {
           type: "agent-switched",
           metadata: event.metadata,
           agent: event.data.agent,
+          previous:
+            event.data.previous ??
+            source.findLast(
+              (item): item is Extract<SessionMessageInfo, { type: "agent-switched" | "assistant" }> =>
+                item.type === "agent-switched" || item.type === "assistant",
+            )?.agent,
           time: { created: event.created },
         })
       case "session.model.selected":
@@ -69,10 +75,12 @@ export function createV2SessionReducer() {
           type: "model-switched",
           metadata: event.metadata,
           model: event.data.model,
-          previous: source.findLast(
-            (item): item is Extract<SessionMessageInfo, { type: "model-switched" | "assistant" }> =>
-              item.type === "model-switched" || item.type === "assistant",
-          )?.model,
+          previous:
+            event.data.previous ??
+            source.findLast(
+              (item): item is Extract<SessionMessageInfo, { type: "model-switched" | "assistant" }> =>
+                item.type === "model-switched" || item.type === "assistant",
+            )?.model,
           time: { created: event.created },
         })
       case "session.synthetic":

packages/client/src/effect/api/api.ts

@@ -339,7 +339,11 @@ export type Endpoint5_31Output =
           readonly type: "session.agent.selected"
           readonly durable: { readonly aggregateID: string; readonly seq: Event.Seq; readonly version: Event.Version }
           readonly location?: Location.Ref | undefined
-          readonly data: { readonly sessionID: Session.ID; readonly agent: Agent.ID }
+          readonly data: {
+            readonly sessionID: Session.ID
+            readonly agent: Agent.ID
+            readonly previous?: Agent.ID | undefined
+          }
         }
       | {
           readonly id: Event.ID
@@ -348,7 +352,11 @@ export type Endpoint5_31Output =
           readonly type: "session.model.selected"
           readonly durable: { readonly aggregateID: string; readonly seq: Event.Seq; readonly version: Event.Version }
           readonly location?: Location.Ref | undefined
-          readonly data: { readonly sessionID: Session.ID; readonly model: Model.Ref }
+          readonly data: {
+            readonly sessionID: Session.ID
+            readonly model: Model.Ref
+            readonly previous?: Model.Ref | undefined
+          }
         }
       | {
           readonly id: Event.ID

packages/client/src/promise/generated/types.ts

@@ -436,7 +436,7 @@ export type SessionAgentSelected = {
   type: "session.agent.selected"
   durable: { aggregateID: string; seq: number; version: 1 }
   location?: LocationRef
-  data: { sessionID: string; agent: string }
+  data: { sessionID: string; agent: string; previous?: string }
 }
 
 export type SessionModelSelected = {
@@ -446,7 +446,7 @@ export type SessionModelSelected = {
   type: "session.model.selected"
   durable: { aggregateID: string; seq: number; version: 1 }
   location?: LocationRef
-  data: { sessionID: string; model: ModelRef }
+  data: { sessionID: string; model: ModelRef; previous?: ModelRef }
 }
 
 export type SessionMoved = {

packages/core/script/migration.ts

@@ -194,11 +194,10 @@ async function formatTypescript(input: string) {
 
 function renderRegistry(names: string[]) {
   return `import type { DatabaseMigration } from "./migration"
+${names.map((name, index) => `import m${index.toString().padStart(2, "0")} from "./migration/${name}"`).join("\n")}
 
-export const migrations: DatabaseMigration.Migration[] = (
-  await Promise.all([
-${names.map((name) => `    import("./migration/${name}"),`).join("\n")}
-  ])
-).map((module) => module.default)
+export const migrations = [
+${names.map((_, index) => `  m${index.toString().padStart(2, "0")},`).join("\n")}
+] satisfies DatabaseMigration.Migration[]
 `
 }

packages/core/src/config/plugin/source.ts

@@ -153,10 +153,12 @@ const scan = Effect.fn("ConfigPluginSource.scan")(function* (
   })
 })
 
+const sourceDirectories = ["plugin", "plugins"] as const
+
 function discoverDirectory(fs: FSUtil.Interface, directory: string) {
   return Effect.gen(function* () {
     const files = yield* fs
-      .scan("{plugin,plugins}/*.{ts,js}", {
+      .scan(`{${sourceDirectories.join(",")}}/*.{ts,js}`, {
         cwd: directory,
         absolute: true,
         include: "file",
@@ -168,8 +170,6 @@ function discoverDirectory(fs: FSUtil.Interface, directory: string) {
   })
 }
 
-const sourceDirectories = ["plugin", "plugins"] as const
-
 function isPluginSource(entries: readonly Entry[], file: string) {
   return entries.some(
     (entry) =>

packages/core/src/database/database.ts

@@ -42,10 +42,10 @@ const databaseLayer = Layer.effect(
 export function layer(options: Options = { path: ":memory:" }) {
   return Layer.unwrap(
     Effect.gen(function* () {
-      const global = yield* Global.Service
       const provide = (filename: string) => databaseLayer.pipe(Layer.provide(sqliteLayer({ filename })))
       const filename = options.path ?? ":memory:"
       if (filename === ":memory:" || isAbsolute(filename)) return provide(filename)
+      const global = yield* Global.Service
       return provide(join(global.data, filename))
     }),
   )

packages/core/src/database/migration.gen.ts

@@ -1,47 +1,86 @@
 import type { DatabaseMigration } from "./migration"
+import m00 from "./migration/20260127222353_familiar_lady_ursula"
+import m01 from "./migration/20260211171708_add_project_commands"
+import m02 from "./migration/20260213144116_wakeful_the_professor"
+import m03 from "./migration/20260225215848_workspace"
+import m04 from "./migration/20260227213759_add_session_workspace_id"
+import m05 from "./migration/20260228203230_blue_harpoon"
+import m06 from "./migration/20260303231226_add_workspace_fields"
+import m07 from "./migration/20260309230000_move_org_to_state"
+import m08 from "./migration/20260312043431_session_message_cursor"
+import m09 from "./migration/20260323234822_events"
+import m10 from "./migration/20260410174513_workspace-name"
+import m11 from "./migration/20260413175956_chief_energizer"
+import m12 from "./migration/20260423070820_add_icon_url_override"
+import m13 from "./migration/20260427172553_slow_nightmare"
+import m14 from "./migration/20260428004200_add_session_path"
+import m15 from "./migration/20260501142318_next_venus"
+import m16 from "./migration/20260504145000_add_sync_owner"
+import m17 from "./migration/20260507164347_add_workspace_time"
+import m18 from "./migration/20260510033149_session_usage"
+import m19 from "./migration/20260511000411_data_migration_state"
+import m20 from "./migration/20260511173437_session-metadata"
+import m21 from "./migration/20260601010001_normalize_storage_paths"
+import m22 from "./migration/20260601202201_amazing_prowler"
+import m23 from "./migration/20260602002951_lowly_union_jack"
+import m24 from "./migration/20260602182828_add_project_directories"
+import m25 from "./migration/20260603001617_session_message_projection_indexes"
+import m26 from "./migration/20260603040000_session_message_projection_order"
+import m27 from "./migration/20260603141458_session_input_inbox"
+import m28 from "./migration/20260603160727_jittery_ezekiel_stane"
+import m29 from "./migration/20260604172448_event_sourced_session_input"
+import m30 from "./migration/20260605003541_add_session_context_snapshot"
+import m31 from "./migration/20260605042240_add_context_epoch_agent"
+import m32 from "./migration/20260611035744_credential"
+import m33 from "./migration/20260611192811_lush_chimera"
+import m34 from "./migration/20260612174303_project_dir_strategy"
+import m35 from "./migration/20260622142730_simplify_session_context_epoch"
+import m36 from "./migration/20260622170816_reset_v2_session_state"
+import m37 from "./migration/20260622202450_simplify_session_input"
+import m38 from "./migration/20260804233008_loose_psylocke"
+import m39 from "./migration/20260805200742_import_legacy_credentials"
+import m40 from "./migration/20260808023530_workspace_domain"
 
-export const migrations: DatabaseMigration.Migration[] = (
-  await Promise.all([
-    import("./migration/20260127222353_familiar_lady_ursula"),
-    import("./migration/20260211171708_add_project_commands"),
-    import("./migration/20260213144116_wakeful_the_professor"),
-    import("./migration/20260225215848_workspace"),
-    import("./migration/20260227213759_add_session_workspace_id"),
-    import("./migration/20260228203230_blue_harpoon"),
-    import("./migration/20260303231226_add_workspace_fields"),
-    import("./migration/20260309230000_move_org_to_state"),
-    import("./migration/20260312043431_session_message_cursor"),
-    import("./migration/20260323234822_events"),
-    import("./migration/20260410174513_workspace-name"),
-    import("./migration/20260413175956_chief_energizer"),
-    import("./migration/20260423070820_add_icon_url_override"),
-    import("./migration/20260427172553_slow_nightmare"),
-    import("./migration/20260428004200_add_session_path"),
-    import("./migration/20260501142318_next_venus"),
-    import("./migration/20260504145000_add_sync_owner"),
-    import("./migration/20260507164347_add_workspace_time"),
-    import("./migration/20260510033149_session_usage"),
-    import("./migration/20260511000411_data_migration_state"),
-    import("./migration/20260511173437_session-metadata"),
-    import("./migration/20260601010001_normalize_storage_paths"),
-    import("./migration/20260601202201_amazing_prowler"),
-    import("./migration/20260602002951_lowly_union_jack"),
-    import("./migration/20260602182828_add_project_directories"),
-    import("./migration/20260603001617_session_message_projection_indexes"),
-    import("./migration/20260603040000_session_message_projection_order"),
-    import("./migration/20260603141458_session_input_inbox"),
-    import("./migration/20260603160727_jittery_ezekiel_stane"),
-    import("./migration/20260604172448_event_sourced_session_input"),
-    import("./migration/20260605003541_add_session_context_snapshot"),
-    import("./migration/20260605042240_add_context_epoch_agent"),
-    import("./migration/20260611035744_credential"),
-    import("./migration/20260611192811_lush_chimera"),
-    import("./migration/20260612174303_project_dir_strategy"),
-    import("./migration/20260622142730_simplify_session_context_epoch"),
-    import("./migration/20260622170816_reset_v2_session_state"),
-    import("./migration/20260622202450_simplify_session_input"),
-    import("./migration/20260804233008_loose_psylocke"),
-    import("./migration/20260805200742_import_legacy_credentials"),
-    import("./migration/20260808023530_workspace_domain"),
-  ])
-).map((module) => module.default)
+export const migrations = [
+  m00,
+  m01,
+  m02,
+  m03,
+  m04,
+  m05,
+  m06,
+  m07,
+  m08,
+  m09,
+  m10,
+  m11,
+  m12,
+  m13,
+  m14,
+  m15,
+  m16,
+  m17,
+  m18,
+  m19,
+  m20,
+  m21,
+  m22,
+  m23,
+  m24,
+  m25,
+  m26,
+  m27,
+  m28,
+  m29,
+  m30,
+  m31,
+  m32,
+  m33,
+  m34,
+  m35,
+  m36,
+  m37,
+  m38,
+  m39,
+  m40,
+] satisfies DatabaseMigration.Migration[]

packages/core/src/models-dev.ts

@@ -1,4 +1,4 @@
-import { Context, Duration, Effect, Layer, Option, Schedule, Schema, Semaphore } from "effect"
+import { Cause, Context, Duration, Effect, Layer, Option, Schedule, Schema, Semaphore } from "effect"
 import { HttpClient, HttpClientRequest } from "effect/unstable/http"
 import { ModelsDev } from "@opencode-ai/schema/models-dev"
 import { Money } from "@opencode-ai/schema/money"
@@ -612,7 +612,16 @@ export const layer = (options?: Options) =>
       const fetchAndWrite = Effect.fn("ModelsDev.fetchAndWrite")(function* () {
         const text = yield* fetchApi()
         const catalog = (yield* Schema.decodeUnknownEffect(CatalogJson)(text)) as Record<string, SourceProvider>
-        yield* kv.set(key, { updatedAt: Date.now(), body: text })
+        // Best-effort: a cache-write failure must never kill catalog
+        // population. The payload has outgrown some KV backends' per-value
+        // limits (Durable Object SQLite caps values at 2 MB and api.json
+        // passed it in Aug 2026); a boot without a cache hit just refetches.
+        yield* kv.set(key, { updatedAt: Date.now(), body: text }).pipe(
+          Effect.catchCauseIf(
+            (cause) => !Cause.hasInterruptsOnly(cause),
+            (cause) => Effect.logWarning("Failed to cache models.dev catalog", { cause }),
+          ),
+        )
         return catalog
       })
 

packages/core/src/plugin/agent.ts

@@ -101,16 +101,6 @@ export const Plugin = define({
         item.permissions.push({ action: "question", resource: "*", effect: "allow" })
       })
 
-      draft.update(Agent.ID.make("plan"), (item) => {
-        item.name = Agent.Name.make("Plan")
-        item.description = "Plan mode. Disallows all edit tools."
-        item.mode = "primary"
-        item.permissions.push(
-          { action: "question", resource: "*", effect: "allow" },
-          { action: "edit", resource: "*", effect: "deny" },
-        )
-      })
-
       draft.update(Agent.ID.make("general"), (item) => {
         item.name = Agent.Name.make("General")
         item.description =

packages/core/src/plugin/internal.ts

@@ -60,6 +60,7 @@ import { WellKnown } from "../wellknown"
 import { WriteTool } from "../tool/plugin/write"
 import { AgentPlugin } from "./agent"
 import { CommandPlugin } from "./command"
+import { PlanPlugin } from "./plan"
 import { ModelsDevPlugin } from "./models-dev"
 import { ProviderPlugins } from "./provider"
 import { WebSearchPlugins } from "./websearch"
@@ -192,6 +193,7 @@ export type InternalPlugin = Plugin<Requirements | Scope.Scope>
 const pre = [
   WellKnownPlugin.Plugin,
   AgentPlugin.Plugin,
+  PlanPlugin.Plugin,
   CommandPlugin.Plugin,
   SkillPlugin.Plugin,
   ...SystemPromptPlugin.Plugins,

packages/core/src/plugin/models-dev.ts

@@ -36,6 +36,7 @@ export const ModelsDevPlugin = define({
           draft.integrationID = Integration.ID.make(provider.info.id)
         })
         for (const model of provider.models) {
+          if (model.status === "deprecated") continue
           catalog.model.update(provider.info.id, model.id, (draft) => Object.assign(draft, model))
         }
       }

packages/core/src/plugin/plan.ts

@@ -0,0 +1,55 @@
+export * as PlanPlugin from "./plan"
+
+import { ToolFailure } from "@opencode-ai/ai"
+import { define } from "@opencode-ai/plugin/effect/plugin"
+import { Effect, Stream } from "effect"
+import { Agent } from "../agent"
+
+const plan = Agent.ID.make("plan")
+
+const enter = `<system-reminder>
+You are in Plan mode. This is a READ-ONLY environment. You are not allowed to edit files, and you may not ask a subagent to edit them either.
+</system-reminder>`
+
+const leave = `<system-reminder>
+You are no longer in Plan mode. The previous read-only restrictions no longer apply. You may edit files again.
+</system-reminder>`
+
+export const Plugin = define({
+  id: "opencode.plan",
+  effect: Effect.fn(function* (ctx) {
+    yield* ctx.agent.transform((draft) => {
+      draft.update(plan, (item) => {
+        item.name = Agent.Name.make("Plan")
+        item.description = "Read-only agent for exploring the codebase and planning work before implementation."
+        item.mode = "primary"
+        item.permissions.push({ action: "question", resource: "*", effect: "allow" })
+      })
+    })
+
+    yield* ctx.tool.hook("execute.before", (event) => {
+      if (event.agent !== plan) return Effect.void
+      if (event.tool !== "edit" && event.tool !== "write" && event.tool !== "patch") return Effect.void
+      return new ToolFailure({
+        message: `Cannot use ${event.tool} in Plan mode. You are in a read-only mode and must not modify files.`,
+      })
+    })
+
+    yield* ctx.event.subscribe().pipe(
+      Stream.filter((event) => event.type === "session.agent.selected"),
+      Stream.runForEach((event) => {
+        if (event.data.agent === event.data.previous) return Effect.void
+        const text = event.data.agent === plan ? enter : event.data.previous === plan ? leave : undefined
+        if (!text) return Effect.void
+        return ctx.session
+          .synthetic({
+            sessionID: event.data.sessionID,
+            text,
+            resume: false,
+          })
+          .pipe(Effect.catch(() => Effect.void))
+      }),
+      Effect.forkScoped({ startImmediately: true }),
+    )
+  }),
+})

packages/core/src/session.ts

@@ -716,10 +716,11 @@ const layer = Layer.effect(
             .pipe(Effect.ignore, Effect.forkIn(scope, { startImmediately: true }), Effect.asVoid)
       }),
       switchAgent: Effect.fn("Session.switchAgent")(function* (input) {
-        yield* result.get(input.sessionID)
+        const session = yield* result.get(input.sessionID)
         yield* bus.publish(SessionEvent.AgentSelected, {
           sessionID: input.sessionID,
           agent: input.agent,
+          previous: session.agent,
         })
       }),
       switchModel: Effect.fn("Session.switchModel")(function* (input) {
@@ -733,6 +734,7 @@ const layer = Layer.effect(
         yield* bus.publish(SessionEvent.ModelSelected, {
           sessionID: input.sessionID,
           model: input.model,
+          previous: session.model,
         })
       }),
       rename: Effect.fn("Session.rename")(function* (input) {

packages/core/src/session/message-updater.ts

@@ -61,7 +61,7 @@ export function update(adapter: Adapter, event: SessionEvent.DurableEvent) {
       "session.usage.recorded": () => Effect.void,
       "session.agent.selected": (event) => {
         return Effect.gen(function* () {
-          const previous = yield* adapter.getAgent()
+          const previous = event.data.previous ?? (yield* adapter.getAgent())
           yield* adapter.appendMessage(
             SessionMessage.AgentSelected.make({
               id: SessionMessage.ID.fromEvent(event.id),
@@ -76,7 +76,7 @@ export function update(adapter: Adapter, event: SessionEvent.DurableEvent) {
       },
       "session.model.selected": (event) => {
         return Effect.gen(function* () {
-          const previous = yield* adapter.getModel()
+          const previous = event.data.previous ?? (yield* adapter.getModel())
           yield* adapter.appendMessage(
             SessionMessage.ModelSelected.make({
               id: SessionMessage.ID.fromEvent(event.id),

packages/core/src/session/runner/to-llm-message.ts

@@ -65,15 +65,15 @@ const userAttachmentContent = (files: readonly FileAttachment[]) => {
   )
   if (eligible.length < 2) return files.flatMap(attachmentContent)
 
-  const seen = new Map<string, string[]>()
+  const seen = new Map<string, Set<string>>()
   return files.flatMap((file) => {
     if (!imageMimes.has(file.mime) || file.source.type !== "inline" || !file.mention?.text)
       return attachmentContent(file)
     const metadata = JSON.stringify([file.mime, file.name ?? null, file.description ?? null, file.mention.text])
-    const matches = seen.get(metadata)
-    if (matches?.includes(file.data)) return []
-    if (matches) matches.push(file.data)
-    if (!matches) seen.set(metadata, [file.data])
+    const payloads = seen.get(metadata) ?? new Set<string>()
+    if (payloads.has(file.data)) return []
+    payloads.add(file.data)
+    seen.set(metadata, payloads)
     return attachmentContent(file)
   })
 }

packages/core/test/agent.test.ts

@@ -165,7 +165,6 @@ describe("Agent", () => {
         "compaction",
         "explore",
         "general",
-        "plan",
         "summary",
         "title",
       ])

packages/core/test/models.test.ts

@@ -185,6 +185,15 @@ const buildLayer = (state: Ref.Ref<MockState>, cache: MockCache, options: Models
     ]),
   )
 
+// Mirrors production KV backends whose writes die as defects (e.g. Durable
+// Object SQLite rejecting values over its 2 MB cap with EffectDrizzleQueryError).
+const makeFailingWriteKV = (cache: MockCache) =>
+  Layer.mock(KV.Service, {
+    get: (key) => Effect.sync(() => cache.values.get(key)),
+    set: () => Effect.die(new Error('Failed query: insert into "kv"')),
+    remove: (key) => Effect.sync(() => cache.values.delete(key)).pipe(Effect.asVoid),
+  })
+
 const makeCache = (): MockCache => ({ values: new Map() })
 
 const writeCacheText = (cache: MockCache, text: string, updatedAt = Date.now()) =>
@@ -248,6 +257,25 @@ describe("ModelsDev Service", () => {
     }),
   )
 
+  it.live("get() still populates the catalog when the KV cache write fails", () =>
+    Effect.gen(function* () {
+      const cache = makeCache()
+      const state = yield* Ref.make({ ...initialState, body: JSON.stringify(fixture2) })
+      const layer = Layer.fresh(
+        AppNodeBuilder.build(ModelsDev.node, [
+          [ModelsDev.node, ModelsDev.configured({ fetch: true })],
+          [LayerNodePlatform.httpClient, Layer.succeed(HttpClient.HttpClient, makeMockClient(state))],
+          [KV.node, makeFailingWriteKV(cache)],
+        ]),
+      )
+      const result = yield* ModelsDev.Service.use((s) => s.get()).pipe(Effect.provide(layer))
+      expect(result).toEqual(fixture2Snapshot)
+      expect(cache.values.has(cacheKey)).toBe(false)
+      const final = yield* Ref.get(state)
+      expect(final.calls.length).toBe(1)
+    }),
+  )
+
   it.live("uses the default models URL when the configured URL is empty", () =>
     Effect.gen(function* () {
       const cache = makeCache()

packages/core/test/plugin/models-dev.test.ts

@@ -215,6 +215,66 @@ describe("ModelsDevPlugin", () => {
     }),
   )
 
+  it.effect("omits deprecated models from the catalog", () =>
+    Effect.gen(function* () {
+      const integrations = yield* Integration.Service
+      const catalog = yield* Catalog.Service
+      const providerID = Provider.ID.make("acme")
+      const activeID = Model.ID.make("current")
+      const deprecatedID = Model.ID.make("legacy")
+      const model = {
+        modelID: activeID,
+        providerID,
+        name: "Current",
+        capabilities: { tools: true, input: [], output: [] },
+        variants: [],
+        time: { released: Date.parse("2026-01-01") },
+        cost: [],
+        status: "active",
+        enabled: true,
+        limit: { context: 128_000, output: 32_000 },
+      } satisfies Omit<Model.Info, "id">
+      const snapshots = [
+        {
+          info: {
+            id: providerID,
+            name: "Acme",
+            package: Provider.aisdk("@ai-sdk/openai-compatible"),
+          },
+          environment: [],
+          models: [
+            { id: activeID, ...model },
+            {
+              id: deprecatedID,
+              ...model,
+              modelID: deprecatedID,
+              name: "Legacy",
+              status: "deprecated" as const,
+            },
+          ],
+        },
+      ] satisfies readonly ModelsDev.Snapshot[]
+
+      yield* ModelsDevPlugin.effect(
+        host({
+          catalog: catalogHost(catalog),
+          integration: integrationHost(integrations),
+        }),
+      ).pipe(
+        Effect.provideService(
+          ModelsDev.Service,
+          ModelsDev.Service.of({
+            get: () => Effect.succeed(snapshots),
+            refresh: () => Effect.void,
+          }),
+        ),
+      )
+
+      expect(yield* catalog.model.get(providerID, activeID)).toBeDefined()
+      expect(yield* catalog.model.get(providerID, deprecatedID)).toBeUndefined()
+    }),
+  )
+
   it.effect("registers key methods for providers with environment variables", () =>
     Effect.gen(function* () {
       const integrations = yield* Integration.Service

packages/core/test/session-create.test.ts

@@ -654,7 +654,7 @@ describe("Session.create", () => {
       expect(yield* session.get(created.id)).toMatchObject({ agent: "plan" })
       expect(
         Array.from(yield* logEvents(session, created.id, true).pipe(Stream.drop(1), Stream.take(1), Stream.runCollect)),
-      ).toMatchObject([{ type: "session.agent.selected", data: { agent: "plan" } }])
+      ).toMatchObject([{ type: "session.agent.selected", data: { agent: "plan", previous: "build" } }])
       expect(yield* session.messages({ sessionID: created.id, order: "asc" })).toMatchObject([
         { type: "agent-switched", agent: "plan", previous: "build" },
       ])
@@ -678,7 +678,12 @@ describe("Session.create", () => {
   it.effect("switches the selected model through the durable Session event", () =>
     Effect.gen(function* () {
       const session = yield* Session.Service
-      const created = yield* session.create({ location })
+      const previous = Model.Ref.make({
+        id: Model.ID.make("haiku"),
+        providerID: Provider.ID.anthropic,
+        variant: Model.VariantID.make("default"),
+      })
+      const created = yield* session.create({ location, model: previous })
       const model = Model.Ref.make({
         id: Model.ID.make("sonnet"),
         providerID: Provider.ID.anthropic,
@@ -692,7 +697,10 @@ describe("Session.create", () => {
         yield* logEvents(session, created.id, true).pipe(Stream.drop(1), Stream.take(1), Stream.runCollect),
       )
       expect(bus).toMatchObject([{ type: "session.model.selected" }])
-      expect(bus[0]?.data).toEqual({ sessionID: created.id, model })
+      expect(bus[0]?.data).toEqual({ sessionID: created.id, model, previous })
+      expect(yield* session.messages({ sessionID: created.id, order: "asc" })).toMatchObject([
+        { type: "model-switched", model, previous },
+      ])
     }),
   )
 

packages/merman/src/core/spatial.ts

@@ -77,20 +77,21 @@ export function spatialPathSpans(points: readonly DiagramPoint[]): SpatialSpan[]
     .sort(([left], [right]) => left - right)
     .flatMap(([y, xs]) => {
       const sorted = [...xs].sort((left, right) => left - right)
+      const [first, ...rest] = sorted
+      if (first === undefined) return []
       const spans: SpatialSpan[] = []
-      let start = sorted[0]
-      let end = start
-      if (start === undefined) return spans
-      for (const x of sorted.slice(1)) {
-        if (x === end! + 1) {
+      let start = first
+      let end = first
+      for (const x of rest) {
+        if (x === end + 1) {
           end = x
           continue
         }
-        spans.push(normalizedSpan(y, start, end!))
+        spans.push(normalizedSpan(y, start, end))
         start = x
         end = x
       }
-      spans.push(normalizedSpan(y, start, end!))
+      spans.push(normalizedSpan(y, start, end))
       return spans
     })
 }

packages/protocol/openapi.json

@@ -14300,9 +14300,15 @@
               "agent": {
                 "type": "string"
               },
+              "previous": {
+                "type": "string"
+              },
               "model": {
                 "$ref": "#/components/schemas/Model.Ref"
               },
+              "previous": {
+                "$ref": "#/components/schemas/Model.Ref"
+              },
               "version": {
                 "type": "string"
               }

packages/schema/src/session-event.ts

@@ -69,6 +69,7 @@ export const AgentSelected = Event.durable({
   schema: {
     ...Base,
     agent: Agent.ID,
+    previous: Agent.ID.pipe(optional),
   },
 })
 export type AgentSelected = typeof AgentSelected.Type
@@ -79,6 +80,7 @@ export const ModelSelected = Event.durable({
   schema: {
     ...Base,
     model: Model.Ref,
+    previous: Model.Ref.pipe(optional),
   },
 })
 export type ModelSelected = typeof ModelSelected.Type

packages/tui/src/component/session-tabs.tsx

@@ -62,13 +62,9 @@ function createMarquee(hovered: () => string | undefined, animations: () => bool
   const leading = createAnimatable({ opacity: 0 }, { enabled: animations, transition: tween({ duration: 0.25 }) })
 
   createEffect(() => {
-    if (!hovered()) {
-      setOffset(0)
-      leading.jump({ opacity: 0 })
-      return
-    }
     setOffset(0)
     leading.jump({ opacity: 0 })
+    if (!hovered()) return
     let interval: ReturnType<typeof setInterval> | undefined
     const delay = setTimeout(() => {
       setOffset(1)

packages/tui/src/prompt/attachment.ts

@@ -25,14 +25,14 @@ function deduplicateByIdentity<T>(
   items: readonly T[],
   identity: (item: T) => { metadata: string; payload: string } | undefined,
 ) {
-  const seen = new Map<string, string[]>()
+  const seen = new Map<string, Set<string>>()
   return items.filter((item) => {
     const key = identity(item)
     if (!key) return true
-    const matches = seen.get(key.metadata)
-    if (matches?.includes(key.payload)) return false
-    if (matches) matches.push(key.payload)
-    if (!matches) seen.set(key.metadata, [key.payload])
+    const payloads = seen.get(key.metadata) ?? new Set<string>()
+    if (payloads.has(key.payload)) return false
+    payloads.add(key.payload)
+    seen.set(key.metadata, payloads)
     return true
   })
 }
@@ -42,7 +42,7 @@ export function deduplicatePromptImages(files: readonly PromptFile[] | undefined
   return deduplicateByIdentity(files, (file) =>
     file.uri.startsWith("data:image/") && file.mention?.text
       ? {
-          metadata: JSON.stringify([attachmentMetadata(file), file.mention.text]),
+          metadata: JSON.stringify([file.name ?? null, file.description ?? null, file.mention.text]),
           payload: file.uri,
         }
       : undefined,

packages/www/openapi.json

@@ -14300,9 +14300,15 @@
               "agent": {
                 "type": "string"
               },
+              "previous": {
+                "type": "string"
+              },
               "model": {
                 "$ref": "#/components/schemas/Model.Ref"
               },
+              "previous": {
+                "$ref": "#/components/schemas/Model.Ref"
+              },
               "version": {
                 "type": "string"
               }

packages/www/public/openapi.json

@@ -14300,9 +14300,15 @@
               "agent": {
                 "type": "string"
               },
+              "previous": {
+                "type": "string"
+              },
               "model": {
                 "$ref": "#/components/schemas/Model.Ref"
               },
+              "previous": {
+                "$ref": "#/components/schemas/Model.Ref"
+              },
               "version": {
                 "type": "string"
               }