fix(workspace-context): rearm compacted baseline

packages/context/workspace-context/README.i18n.yaml

@@ -1,6 +1,6 @@
 # Bilingual-pair consistency record (docs/i18n/README.md): the git blob hash of each
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
-#   pnpm run verify-translation-pairing --write
-README.md: bf0180f191395f6af81ce6fe5b6497810596fc29
-README.zh.md: d544d1c8373de0064b87f466829b523308991741
+#   pnpm run verify-translation-pairing --write packages/context/workspace-context/README.md
+README.md: df75b29dd3e8dbb504aac9e9885c32a809cbf70f
+README.zh.md: 8bd926302f09ecdf453c7832b3a15b0e7fcc1b2a

packages/context/workspace-context/README.md

@@ -48,11 +48,11 @@ The plugin owns the complete `<system-reminder>` framing, and every injected `us
 
 ## State And Refresh
 
-Model-visible text contains no hidden state markers. Each dynamic context event instead carries a typed `workspace-instructions` source with a list of `{ action, scope, path, digest? }` changes. On every relevant tool touch, the plugin reconstructs loaded state from its visible session events and overlays a short in-memory pending window for context present on the immutable top-level `tools/result` but not yet appended by the loop. A matching durable `user/message` confirms the pending transition. If the owning `step/end` arrives before a matching context reaches the log, the plugin clears the pending transition and its version fast path so the next successful touch can load it again. Nested Code Mode results stage pending changes under the outer execution token for same-run duplicate suppression; the outer result rolls that state back and recommits only contexts that survived outer policy.
+Model-visible text contains no hidden state markers. Each baseline or dynamic context event instead carries a typed `workspace-instructions` source with a list of `{ action, scope, path, digest? }` changes; the complete startup or resume baseline also carries `baseline: true`. On every relevant tool touch, the plugin reconstructs loaded state from its visible session events and overlays a short in-memory pending window for context present on the immutable top-level `tools/result` but not yet appended by the loop. A matching durable `user/message` confirms the pending transition. If the owning `step/end` arrives before a matching context reaches the log, the plugin clears the pending transition and its version fast path so the next successful touch can load it again. Nested Code Mode results stage pending changes under the outer execution token for same-run duplicate suppression; the outer result rolls that state back and recommits only contexts that survived outer policy.
 
 An unchanged path and SHA-1 content digest is not injected again. A per-session, per-scope provider cache stores only `{ path, version, digest, trimmedDigest }`: when the provider's opaque `FsVersion` and the effective visible state both match, reconciliation skips the content read; a changed version triggers a bounded read and SHA-1 confirmation before any model-visible update. The `trimmedDigest` — SHA-1 over the whitespace-trimmed content — is the per-directory duplicate key, so an unchanged file can still be removed when an earlier candidate converges on its content. Resume works because SHA-1 state is persisted in the typed source, while an empty in-memory version cache merely causes one confirming read. Compaction re-arms a scope after its context event leaves the visible surface even when the cached version is unchanged. A removal is a tombstone, so a later candidate reappearance is loaded again. Only model-visible changes actually rendered within the byte budget enter the source, pending state, and version cache; an omitted change remains eligible for a later touch, while a same-digest version refresh updates only the provider cache.
 
-The initial baseline event itself is not rewritten. Its path/digest map is retained as comparison state; the next successful filesystem touch appends any baseline replacement or removal. A resumed loop recomposes the current baseline and also reconciles still-visible dynamic scopes before its first request. There is no file watcher, so an on-disk change becomes visible at the next successful `read`, `write`, or `edit` touch, or when a resumed loop prepares its baseline.
+The initial baseline event itself is not rewritten. Its typed changes remain authoritative only while that event is in the visible session surface; the next successful filesystem touch re-adds an unchanged baseline scope after compaction, or appends its replacement or removal. The in-memory scope marker and provider-version cache only select and accelerate probes. A hot plugin remount retains a baseline only when its typed event remains visible, while rebuilding current scope and version tracking; otherwise it injects a current baseline. A resumed loop always recomposes the current baseline and also reconciles still-visible dynamic scopes before its first request. There is no file watcher, so an on-disk change becomes visible at the next successful `read`, `write`, or `edit` touch, or when a resumed loop prepares its baseline.
 
 ## Configuration
 

packages/context/workspace-context/README.zh.md

@@ -48,11 +48,11 @@ These instructions apply to work under `packages/app`. Use them as guidance when
 
 ## 状态与刷新
 
-模型可见文本不含隐藏状态标记。每个动态上下文事件改为携带带类型的 `workspace-instructions` 来源，其中包含 `{ action, scope, path, digest? }` 变更列表。每次相关工具 touch 时，插件会从可见会话事件重建已加载状态，并叠加一个短暂内存 pending 窗口，用于不可变顶层 `tools/result` 上存在但 loop 尚未追加的上下文。匹配的持久 `user/message` 会确认 pending 转换。如果所属 `step/end` 在匹配上下文进入日志之前到达，插件会清除 pending 转换及其版本快速路径，使下一次成功 touch 可以重新加载。嵌套 Code Mode 结果会在外层执行 token 下暂存 pending 变更，用于抑制同次运行中的重复项；外层结果会回滚该状态，再只重新提交经过外层策略的上下文。
+模型可见文本不含隐藏状态标记。每个基线或动态上下文事件改为携带带类型的 `workspace-instructions` 来源，其中包含 `{ action, scope, path, digest? }` 变更列表；完整的启动或恢复基线还会携带 `baseline: true`。每次相关工具 touch 时，插件会从可见会话事件重建已加载状态，并叠加一个短暂内存 pending 窗口，用于不可变顶层 `tools/result` 上存在但 loop 尚未追加的上下文。匹配的持久 `user/message` 会确认 pending 转换。如果所属 `step/end` 在匹配上下文进入日志之前到达，插件会清除 pending 转换及其版本快速路径，使下一次成功 touch 可以重新加载。嵌套 Code Mode 结果会在外层执行 token 下暂存 pending 变更，用于抑制同次运行中的重复项；外层结果会回滚该状态，再只重新提交经过外层策略的上下文。
 
 路径与 SHA-1 内容 digest 都未变时，不会重复注入。每会话、每 scope 提供方 cache 只存储 `{ path, version, digest, trimmedDigest }`：当提供方的不透明 `FsVersion` 与有效可见状态都匹配时，对账会跳过内容读取；版本改变会在任何模型可见更新之前触发有界读取与 SHA-1 确认。`trimmedDigest` 是针对去除空白后内容的 SHA-1，也是每目录重复 key，因此较早候选文件与某个未更改文件的内容收敛后，后者仍可被移除。恢复可行，因为 SHA-1 状态持久化在带类型的来源中，而空的内存版本 cache 只会导致一次确认读取。压缩会在 scope 的上下文事件离开可见表层后重新启用它，即使缓存版本未变。移除是 tombstone，因此候选文件之后重新出现时会重新加载。只有在字节预算内实际渲染的模型可见变更才会进入来源、pending 状态和版本 cache；已省略变更仍可在后续 touch 处理，而相同 digest 的版本刷新只更新提供方 cache。
 
-初始基线事件自身不会被改写。其路径／digest map 保留为比较状态；下一次成功文件系统 touch 会追加任何基线替换或移除。恢复的 loop 会重新组合当前基线，并在第一个请求前对账仍可见的动态 scope。没有文件 watcher，因此磁盘变更会在下一次成功 `read`、`write` 或 `edit` touch 时可见，也会在恢复 loop 准备基线时可见。
+初始基线事件自身不会被改写。其带类型的变更仅在该事件仍位于可见会话表层时才是权威状态；下一次成功的文件系统 touch 会在压缩后重新添加未变的基线 scope，或追加其替换或移除。内存中的 scope 标记和提供方版本 cache 只负责选择探测对象并加速探测。插件热重挂只有在其带类型的事件仍然可见时才保留基线，同时会重建当前 scope 与版本跟踪状态；否则会注入当前基线。恢复的 loop 始终重新组合当前基线，并在第一个请求前对账仍可见的动态 scope。没有文件 watcher，因此磁盘变更会在下一次成功 `read`、`write` 或 `edit` touch 时可见，也会在恢复 loop 准备基线时可见。
 
 ## 配置
 

packages/context/workspace-context/src/index.ts

@@ -43,19 +43,27 @@ export type {
 export { renderWorkspaceContext } from './render.ts'
 export type { RenderedWorkspaceContext, TruncatedInstruction } from './render.ts'
 
+function hasVisibleBaseline(agent: Agent): boolean {
+  return agent.session.surface.nodes.some((seq) => {
+    const event = agent.session.events[seq]
+    return event?.type === 'user/message'
+      && event.data.source.kind === 'workspace-instructions'
+      && event.data.source.baseline === true
+  })
+}
+
 export function apply(ctx: Context, config: Config): void {
   const resolved: ResolvedConfig = resolveConfig(config)
   const pendingNestedChanges = new WeakMap<object, Map<string, PendingInstructionChange>>()
-  const baselineInstructionStates = new WeakMap<object, Map<string, WorkspaceInstructionChange>>()
+  const baselineSessions = new WeakSet<object>()
   const instructionVersions: InstructionVersionCache = new WeakMap()
   const pendingVersionUpdates = new Map<ToolExecutionToken, InstructionVersionUpdate[]>()
   const baselineLoaded = new WeakSet<object>()
   // Sessions whose lifecycle start this mount witnessed. A startup or resume
   // emits agent/session-start before the first step; a hot remount attaches to
-  // an already-live session and never sees it. That difference is the only
-  // reliable way to tell a resumed session (re-compose the baseline from
-  // current files) from a remount over a live one (keep the single baseline
-  // already in the log) — the durable log looks identical in both cases.
+  // an already-live session and never sees it. Resumes always re-compose the
+  // baseline from current files. Hot remounts retain a baseline only while its
+  // typed event remains model-visible.
   const lifecycleWitnessed = new WeakSet<object>()
   const pendingByParent = new Map<ToolExecutionToken, {
     agent: Agent
@@ -73,15 +81,6 @@ export function apply(ctx: Context, config: Config): void {
 
   ctx.on('agent/step', async (agent: Agent, _turn, _step, signal): Promise<void> => {
     if (baselineLoaded.has(agent.session)) return
-    // A baseline already in the log with no witnessed lifecycle start is a hot
-    // remount over a live session: keep that single baseline and skip. A
-    // resumed session witnessed its start, so it falls through and re-composes.
-    if (!lifecycleWitnessed.has(agent.session)
-      && agent.session.events.some(event => event.type === 'user/message'
-        && event.data.source.kind === 'plugin' && event.data.source.plugin === 'workspace-context')) {
-      baselineLoaded.add(agent.session)
-      return
-    }
     if (resolved.maxBytes <= 0 || !Number.isFinite(resolved.maxBytes)) {
       baselineLoaded.add(agent.session)
       return
@@ -104,14 +103,13 @@ export function apply(ctx: Context, config: Config): void {
       signal,
     }, fileSystem)
     const baseline = baselineInstructionState(instructions?.included ?? [])
-    baselineInstructionStates.set(agent.session, baseline.changes)
+    baselineSessions.add(agent.session)
     instructionVersions.set(agent.session, baseline.versions)
 
     const update = await reconcileInstructionContext(
       agent,
       resolved,
       pendingNestedChanges,
-      baselineInstructionStates,
       instructionVersions,
       fileSystem,
       { includeBaselineScopes: false, signal },
@@ -120,9 +118,17 @@ export function apply(ctx: Context, config: Config): void {
       agent.inject({ content: update.context.content, source: update.context.source })
       applyInstructionVersionUpdates(agent.session, update.versionUpdates, instructionVersions)
     }
-    if (instructions !== undefined && instructions.rendered.text.length > 0) {
+    const keepVisibleBaseline = !lifecycleWitnessed.has(agent.session) && hasVisibleBaseline(agent)
+    if (!keepVisibleBaseline && instructions !== undefined && instructions.rendered.text.length > 0) {
       const baselineMessage = workspaceContextMessage(instructions.rendered.text)
-      agent.inject({ content: baselineMessage.content, source: { kind: 'plugin', plugin: 'workspace-context' } })
+      agent.inject({
+        content: baselineMessage.content,
+        source: {
+          kind: 'workspace-instructions',
+          baseline: true,
+          changes: [...baseline.changes.values()],
+        },
+      })
     }
     baselineLoaded.add(agent.session)
   })
@@ -148,7 +154,7 @@ export function apply(ctx: Context, config: Config): void {
       result,
       resolved,
       pendingNestedChanges,
-      baselineInstructionStates,
+      baselineSessions,
       instructionVersions,
       fileSystem,
     )

packages/context/workspace-context/src/state.ts

@@ -38,6 +38,8 @@ const FILE_TOUCH_TOOL_NAMES = new Set(['read', 'write', 'edit'])
 /** Durable provenance and reconciliation facts for one workspace context. */
 export interface WorkspaceInstructionSource {
   kind: 'workspace-instructions'
+  /** Marks the complete startup/resume baseline rather than a later delta. */
+  baseline?: true
   changes: WorkspaceInstructionChange[]
 }
 
@@ -89,7 +91,7 @@ function workspaceContextHook(text: string, changes: WorkspaceInstructionChange[
 }
 
 /**
- * Build the request-prefix message for a rendered baseline.
+ * Build the user-role message for a rendered baseline.
  * @param text - complete plugin-owned system-reminder text.
  * @returns a user-role prefix message.
  */
@@ -378,50 +380,49 @@ function relativeScope(projectRoot: string, dir: string): string {
  * @param agent - session owner whose visible surface supplies durable state.
  * @param resolved - normalized plugin configuration.
  * @param pendingBySession - short pending window before returned context is logged.
- * @param baselineBySession - frozen baseline comparison state per session.
  * @param versionCache - per-session scope metadata used to skip unchanged reads.
  * @param fileSystem - provider used for current file probes.
- * @param options - touched path and whether baseline scopes should be checked.
+ * @param options - touched path and whether baseline scopes should participate.
  * @returns rendered context plus deferred cache updates, or undefined when unchanged/unavailable.
  */
 export async function reconcileInstructionContext(
   agent: Agent,
   resolved: ResolvedConfig,
   pendingBySession: WeakMap<object, Map<string, PendingInstructionChange>>,
-  baselineBySession: WeakMap<object, Map<string, WorkspaceInstructionChange>>,
   versionCache: InstructionVersionCache,
   fileSystem: FileSystem,
   options: { touchedPath?: string; includeBaselineScopes: boolean; signal?: AbortSignal },
 ): Promise<ReconciledInstructionContext | undefined> {
   const session = agent.session
   const pending = pendingChangesFor(session, pendingBySession)
-  const visible = visibleInstructionChanges(agent, pending)
-  const effective = new Map(baselineBySession.get(session) ?? [])
-  for (const [scope, change] of visible) effective.set(scope, change)
+  const effective = visibleInstructionChanges(agent, pending)
   /* v8 ignore next -- normal agents carry an absolute session cwd. */
   const cwd = session.header.cwd ?? process.cwd()
   // TODO(frozen-project-root): retain the baseline root for the loop instance;
   // recomputing it after marker edits reinterprets the existing relative scope keys.
   const projectRoot = await findProjectRoot(cwd, resolved.projectRootMarkers, fileSystem, options.signal)
   const scopes = new Set<string>()
-  const addDirScopes = (directory: string): void => {
-    for (const candidate of resolved.instructionFileCandidates) scopes.add(candidateScopeKey(directory, candidate))
-    for (const candidate of resolved.localInstructionFileCandidates) scopes.add(candidateScopeKey(directory, candidate))
+  const baselineScopes = new Set<string>()
+  const addDirScopes = (target: Set<string>, directory: string): void => {
+    for (const candidate of resolved.instructionFileCandidates) target.add(candidateScopeKey(directory, candidate))
+    for (const candidate of resolved.localInstructionFileCandidates) target.add(candidateScopeKey(directory, candidate))
   }
-  const addProjectScopes = (dir: string): void => {
-    addDirScopes(relativeScope(projectRoot, dir))
+  const addProjectScopes = (target: Set<string>, dir: string): void => {
+    addDirScopes(target, relativeScope(projectRoot, dir))
   }
+  baselineScopes.add(candidateScopeKey(USER_GLOBAL_DIRECTORY, USER_GLOBAL_FILE))
+  for (const dir of ancestorChain(projectRoot, cwd)) addProjectScopes(baselineScopes, dir)
   if (options.includeBaselineScopes) {
-    scopes.add(candidateScopeKey(USER_GLOBAL_DIRECTORY, USER_GLOBAL_FILE))
-    for (const dir of ancestorChain(projectRoot, cwd)) addProjectScopes(dir)
+    for (const scope of baselineScopes) scopes.add(scope)
   }
   for (const scope of effective.keys()) {
+    if (!options.includeBaselineScopes && baselineScopes.has(scope)) continue
     const { directory } = decodeScopeKey(scope)
     if (directory === USER_GLOBAL_DIRECTORY) scopes.add(candidateScopeKey(USER_GLOBAL_DIRECTORY, USER_GLOBAL_FILE))
-    else addDirScopes(directory)
+    else addDirScopes(scopes, directory)
   }
   if (options.touchedPath !== undefined) {
-    for (const dir of descendantDirsBetween(cwd, options.touchedPath)) addProjectScopes(dir)
+    for (const dir of descendantDirsBetween(cwd, options.touchedPath)) addProjectScopes(scopes, dir)
   }
 
   const versions = versionStatesFor(session, versionCache)
@@ -533,7 +534,7 @@ export async function reconcileInstructionContext(
  * @param result - original tool result before post-execute decisions.
  * @param resolved - normalized plugin configuration.
  * @param pendingNestedChanges - per-session pending transition maps.
- * @param baselineInstructionStates - retained baseline comparison state.
+ * @param baselineSessions - sessions whose configured baseline scopes should be probed.
  * @param versionCache - per-session scope metadata used to skip unchanged reads.
  * @param fileSystem - provider used for current file probes.
  * @returns rendered context plus deferred cache updates, or undefined for irrelevant/failed/unchanged calls.
@@ -544,7 +545,7 @@ export async function dynamicInstructionContext(
   result: ToolExecutionResult,
   resolved: ResolvedConfig,
   pendingNestedChanges: WeakMap<object, Map<string, PendingInstructionChange>>,
-  baselineInstructionStates: WeakMap<object, Map<string, WorkspaceInstructionChange>>,
+  baselineSessions: WeakSet<object>,
   versionCache: InstructionVersionCache,
   fileSystem: FileSystem,
 ): Promise<ReconciledInstructionContext | undefined> {
@@ -552,10 +553,10 @@ export async function dynamicInstructionContext(
   const touchedPath = filePathFromExecution(exec)
   if (touchedPath === undefined) return undefined
   return reconcileInstructionContext(
-    agent, resolved, pendingNestedChanges, baselineInstructionStates, versionCache, fileSystem,
+    agent, resolved, pendingNestedChanges, versionCache, fileSystem,
     {
       touchedPath,
-      includeBaselineScopes: baselineInstructionStates.has(agent.session),
+      includeBaselineScopes: baselineSessions.has(agent.session),
       signal: exec.signal,
     },
   )

packages/context/workspace-context/tests/workspace-context.spec.ts

@@ -207,6 +207,13 @@ function workspaceContextOf(result: { additionalContexts?: UserMessageData[] }):
     context.source.kind === 'workspace-instructions')
 }
 
+function baselineEvents(agent: Agent): SessionEvent[] {
+  return agent.session.events.filter(event =>
+    event.type === 'user/message'
+    && event.data.source.kind === 'workspace-instructions'
+    && event.data.source.baseline === true)
+}
+
 function workspaceChangeContext(scope: string, digest: string): UserMessageData {
   return {
     content: [{ type: 'text', text: `instructions for ${scope}` }],
@@ -943,9 +950,17 @@ describe('workspace context request injection', () => {
 
       await composeBaselinePrefix(ctx, agent)
 
-      expect(agent.session.events.filter(event =>
-        event.type === 'user/message' && event.data.source.kind !== 'user',
-      )).toHaveLength(1)
+      expect(baselineEvents(agent)).toHaveLength(1)
+      expect(baselineEvents(agent)[0]).toMatchObject({
+        type: 'user/message',
+        data: {
+          source: {
+            kind: 'workspace-instructions',
+            baseline: true,
+            changes: [{ action: 'set', scope: sk('.', 'AGENTS.md'), path: 'AGENTS.md' }],
+          },
+        },
+      })
       expect(composedPrefixes.get(agent)).toHaveLength(1)
       expect(derivedText(agent)).toContain('<system-reminder>')
       expect(derivedText(agent)).toContain('Instructions from: AGENTS.md')
@@ -980,7 +995,44 @@ describe('workspace context request injection', () => {
     }
   })
 
-  it('folds an already-appended baseline from the log after a plugin remount', async () => {
+  it('retains a visible baseline after a plugin remount', async () => {
+    const root = await tempRepo()
+    const home = await tempRepo()
+    try {
+      await mkdir(join(root, '.git'), { recursive: true })
+      await write(join(root, 'AGENTS.md'), 'repo rule')
+      await write(join(root, 'file.txt'), 'hello')
+      const ctx = new Context()
+      const fiber = await mountFileToolsAndWorkspaceContext(ctx, { dshHome: home, maxBytes: 65536 })
+      const agent = stubAgent(root)
+      await composeBaselinePrefix(ctx, agent)
+
+      // Hot remount over the live session: the durable baseline remains
+      // visible, so the fresh mount does not append a duplicate.
+      await fiber.dispose()
+      await ctx.plugin(workspaceContext, { dshHome: home, maxBytes: 65536 })
+      await composeBaselinePrefix(ctx, agent)
+
+      expect(baselineEvents(agent)).toHaveLength(1)
+
+      await write(join(root, 'AGENTS.md'), 'updated repo rule')
+      const update = await ctx.tools.execute({
+        signal: testToolSignal,
+        callId: CallId('read-after-remount'),
+        name: 'read',
+        arguments: { file_path: 'file.txt' },
+        agent,
+      })
+      expect(workspaceContextOf(update)?.source).toMatchObject({
+        changes: [{ action: 'replace', scope: sk('.', 'AGENTS.md'), path: 'AGENTS.md' }],
+      })
+    } finally {
+      await rm(root, { recursive: true, force: true })
+      await rm(home, { recursive: true, force: true })
+    }
+  })
+
+  it('restores a compacted baseline on a hot plugin remount', async () => {
     const root = await tempRepo()
     const home = await tempRepo()
     try {
@@ -991,15 +1043,23 @@ describe('workspace context request injection', () => {
       const fiber = await ctx.plugin(workspaceContext, { dshHome: home, maxBytes: 65536 })
       const agent = stubAgent(root)
       await composeBaselinePrefix(ctx, agent)
+      const baseline = baselineEvents(agent)[0]
+      expect(baseline).toBeDefined()
+
+      agent.session.append('user/message', {
+        content: [{ type: 'text', text: 'compacted summary' }],
+        source: { kind: 'plugin', plugin: 'compact' },
+      }, {
+        surfaceOp: { op: 'replace', start: baseline!.seq, end: baseline!.seq },
+        sourceEventSeqs: [baseline!.seq],
+      })
 
-      // Hot remount over the live session: the durable baseline survived, so
-      // the fresh mount must fold it from the log instead of appending a
-      // duplicate on its next step.
       await fiber.dispose()
       await ctx.plugin(workspaceContext, { dshHome: home, maxBytes: 65536 })
       await composeBaselinePrefix(ctx, agent)
 
-      expect(agent.session.events.filter(event => event.type === 'user/message' && event.data.source.kind !== 'user')).toHaveLength(1)
+      expect(baselineEvents(agent)).toHaveLength(2)
+      expect(blocksText(agent.session.deriveMessages().at(-1)?.content)).toContain('repo rule')
     } finally {
       await rm(root, { recursive: true, force: true })
       await rm(home, { recursive: true, force: true })
@@ -1031,14 +1091,12 @@ describe('workspace context request injection', () => {
       agentEvents(ctx, resumed).emit('agent/session-start', 'resume')
       await composeBaselinePrefix(ctx, resumed)
 
-      const pluginMessages = resumed.session.events.filter(event =>
-        event.type === 'user/message' && event.data.source.kind === 'plugin'
-        && event.data.source.plugin === 'workspace-context')
-      expect(pluginMessages).toHaveLength(2)
-      const latest = pluginMessages.at(-1)
+      const baselines = baselineEvents(resumed)
+      expect(baselines).toHaveLength(2)
+      const latest = baselines.at(-1)
       expect(latest?.type === 'user/message' && blocksText(latest.data.content))
         .toContain('new root rule after offline edit')
-      const original0 = pluginMessages[0]
+      const original0 = baselines[0]
       expect(original0?.type === 'user/message' && blocksText(original0.data.content))
         .toContain('old root rule')
     } finally {
@@ -2657,6 +2715,63 @@ describe('dynamic nested workspace context injection', () => {
     }
   })
 
+  it('re-arms an unchanged baseline after compaction removes it from the surface', async () => {
+    const root = await tempRepo()
+    const home = await tempRepo()
+    try {
+      await mkdir(join(root, '.git'), { recursive: true })
+      await write(join(root, 'AGENTS.md'), 'root rule')
+      await write(join(root, 'file.txt'), 'hello')
+      const ctx = new Context()
+      await mountFileToolsAndWorkspaceContext(ctx, { dshHome: home, maxBytes: 65536 })
+      const agent = stubAgent(root)
+      await composeBaselinePrefix(ctx, agent)
+      const baseline = baselineEvents(agent)[0]
+      expect(baseline).toBeDefined()
+
+      const whileVisible = await ctx.tools.execute({
+        signal: testToolSignal,
+        callId: CallId('read-visible-baseline'),
+        name: 'read',
+        arguments: { file_path: 'file.txt' },
+        agent,
+      })
+      agent.session.append('user/message', {
+        content: [{ type: 'text', text: 'compacted summary' }],
+        source: { kind: 'plugin', plugin: 'compact' },
+      }, {
+        surfaceOp: { op: 'replace', start: baseline!.seq, end: baseline!.seq },
+        sourceEventSeqs: [baseline!.seq],
+      })
+
+      const rearmed = await ctx.tools.execute({
+        signal: testToolSignal,
+        callId: CallId('read-compacted-baseline'),
+        name: 'read',
+        arguments: { file_path: 'file.txt' },
+        agent,
+      })
+      appendAdditionalContexts(agent, rearmed)
+      const afterRearm = await ctx.tools.execute({
+        signal: testToolSignal,
+        callId: CallId('read-rearmed-baseline'),
+        name: 'read',
+        arguments: { file_path: 'file.txt' },
+        agent,
+      })
+
+      expect(whileVisible.additionalContexts).toBeUndefined()
+      expect(workspaceContextOf(rearmed)?.source).toMatchObject({
+        changes: [{ action: 'set', scope: sk('.', 'AGENTS.md'), path: 'AGENTS.md' }],
+      })
+      expect(blocksText(workspaceContextOf(rearmed)?.content)).toContain('root rule')
+      expect(afterRearm.additionalContexts).toBeUndefined()
+    } finally {
+      await rm(root, { recursive: true, force: true })
+      await rm(home, { recursive: true, force: true })
+    }
+  })
+
   it('does not treat markdown headings inside instruction content as loaded instruction metadata', async () => {
     const root = await tempRepo()
     const home = await tempRepo()