diff --git a/src/main/claude/claude-structured-dispatch.test.ts b/src/main/claude/claude-structured-dispatch.test.ts
index 86ab6a45627..1054561f657 100644
--- a/src/main/claude/claude-structured-dispatch.test.ts
+++ b/src/main/claude/claude-structured-dispatch.test.ts
@@ -15,6 +15,7 @@ function sessionFor(send = vi.fn().mockResolvedValue(undefined)): ClaudeSession
     acquisitionGeneration: 'generation-1',
     prompts: {} as ClaudeSession['prompts'],
     dispatchWaiters: [],
+    dispatchSequence: 0,
     options: new Map(),
     reportedOptions: {},
     capabilities: [],
diff --git a/src/main/claude/claude-structured-dispatch.ts b/src/main/claude/claude-structured-dispatch.ts
index 045c18fa6aa..0941f654d64 100644
--- a/src/main/claude/claude-structured-dispatch.ts
+++ b/src/main/claude/claude-structured-dispatch.ts
@@ -169,6 +169,9 @@ export async function dispatchClaudeTurn(
   } catch (error) {
     return { state: 'rejected', reason: (error as Error).message }
   }
+  // Advance before writing so an unknown/late replay still fences cancellation
+  // of the previously acknowledged turn on this session-scoped connection.
+  const dispatchSequence = ++session.dispatchSequence
   const acceptsResult = input.body.blocks.some(
     (block) => block.type === 'text' && block.text.trimStart().startsWith('/')
   )
@@ -193,6 +196,7 @@ export async function dispatchClaudeTurn(
     // Claude's interrupt API is session-scoped, so retain the provider turn
     // identity and let cancellation reject a stale request for an older turn.
     session.activeTurnId = uuid
+    session.activeTurnSequence = dispatchSequence
   }
   return uuid
     ? {
diff --git a/src/main/claude/claude-structured-session-adapter.test.ts b/src/main/claude/claude-structured-session-adapter.test.ts
index 4649b457137..d8cb1632946 100644
--- a/src/main/claude/claude-structured-session-adapter.test.ts
+++ b/src/main/claude/claude-structured-session-adapter.test.ts
@@ -358,6 +358,39 @@ describe('ClaudeStructuredSessionAdapter turns and controls', () => {
     )
   })
 
+  it('does not cancel an acknowledged turn after a later dispatch returns unknown', async () => {
+    const claude = fakeClaude({ replayUuids: ['turn-T', null] })
+    const adapter = await acquired(claude)
+
+    await expect(
+      adapter.dispatch({
+        sessionId: 'session-1',
+        clientMessageId: 'client-T',
+        body: USER_MESSAGE,
+        fence: 7
+      })
+    ).resolves.toMatchObject({
+      state: 'accepted',
+      providerIdentity: { uuid: 'turn-T' }
+    })
+    await expect(
+      adapter.dispatch({
+        sessionId: 'session-1',
+        clientMessageId: 'client-U',
+        body: USER_MESSAGE,
+        fence: 7
+      })
+    ).resolves.toMatchObject({ state: 'unknown' })
+    expect(claude.connections[0].sent).toHaveLength(2)
+
+    await expect(
+      adapter.cancelTurn({ sessionId: 'session-1', turnId: 'turn-T', fence: 7 })
+    ).resolves.toEqual({ cancelled: false })
+    expect(claude.connections[0].calls.filter((call) => call.subtype === 'interrupt')).toHaveLength(
+      0
+    )
+  })
+
   it('classifies provider-declined options without treating timeouts as settled', async () => {
     const claude = fakeClaude({
       routes: {
diff --git a/src/main/claude/claude-structured-session-adapter.ts b/src/main/claude/claude-structured-session-adapter.ts
index e91b1e0e28f..c456288468e 100644
--- a/src/main/claude/claude-structured-session-adapter.ts
+++ b/src/main/claude/claude-structured-session-adapter.ts
@@ -155,7 +155,10 @@ export class ClaudeStructuredSessionAdapter implements StructuredAgentSessionAda
         this.sessions.get(input.sessionId) === session &&
         session.fence === input.fence &&
         session.acquisitionGeneration === acquisitionGeneration &&
-        (session.activeTurnId === undefined || session.activeTurnId === input.turnId)
+        (session.activeTurnId === undefined
+          ? session.dispatchSequence === 0
+          : session.activeTurnId === input.turnId &&
+            session.activeTurnSequence === session.dispatchSequence)
       )
     })
   }
diff --git a/src/main/claude/claude-structured-session-publication.ts b/src/main/claude/claude-structured-session-publication.ts
index 853118f6fa2..a5b8bcfbf56 100644
--- a/src/main/claude/claude-structured-session-publication.ts
+++ b/src/main/claude/claude-structured-session-publication.ts
@@ -44,6 +44,7 @@ export function createClaudeSessionPublication(input: {
       acquisitionGeneration: input.acquisitionGeneration,
       prompts: input.prompts,
       dispatchWaiters: [],
+      dispatchSequence: 0,
       options: new Map(input.options),
       capabilities: input.capabilities,
       reportedOptions: {
diff --git a/src/main/claude/claude-structured-session-state.ts b/src/main/claude/claude-structured-session-state.ts
index b165ba166a6..68558bacb1f 100644
--- a/src/main/claude/claude-structured-session-state.ts
+++ b/src/main/claude/claude-structured-session-state.ts
@@ -95,6 +95,10 @@ export type ClaudeSession = {
   capabilities: readonly string[]
   /** Provider uuid of the most recently admitted turn, if one is active. */
   activeTurnId?: string
+  /** Monotonic fence advanced when a dispatch starts, including unresolved dispatches. */
+  dispatchSequence: number
+  /** Dispatch sequence that admitted activeTurnId. */
+  activeTurnSequence?: number
   translator: ClaudeJournalTranslator | null
   events: StructuredAgentSessionEventSink | undefined
 }
diff --git a/src/main/claude/claude-structured-session-test-support.ts b/src/main/claude/claude-structured-session-test-support.ts
index 8d21e157778..2cb8e15d882 100644
--- a/src/main/claude/claude-structured-session-test-support.ts
+++ b/src/main/claude/claude-structured-session-test-support.ts
@@ -56,7 +56,7 @@ export function fakeClaude(
     exitBeforeInit?: string
     settings?: unknown
     replayUuid?: string | null
-    replayUuids?: string[]
+    replayUuids?: (string | null)[]
     capabilities?: string[]
     unprovenCloseVerdict?: ClaudeStreamJsonConnection['exitVerdict']
     routes?: Record<string, Route>
@@ -149,13 +149,17 @@ export function fakeClaude(
       send: async (message) => {
         connection.sent.push(message)
         if (message.type === 'user' && options.replayUuid !== null) {
-          const replayUuid = options.replayUuids
-            ? (options.replayUuids[replayIndex++] ?? `user-uuid-${replayIndex}`)
-            : (options.replayUuid ?? 'user-uuid')
-          handlers.onMessage?.({
-            ...message,
-            uuid: replayUuid
-          })
+          const configuredReplayUuid = options.replayUuids
+            ? options.replayUuids[replayIndex++]
+            : options.replayUuid
+          const replayUuid =
+            configuredReplayUuid === undefined ? `user-uuid-${replayIndex}` : configuredReplayUuid
+          if (replayUuid !== null) {
+            handlers.onMessage?.({
+              ...message,
+              uuid: replayUuid
+            })
+          }
         }
       },
       exitVerdict: options.unprovenCloseVerdict ?? { root: 'live', tree: 'unverifiable' },