diff --git a/docs/design/2026-07-14-chat-record-daemon-transcript-block-projection.md b/docs/design/2026-07-14-chat-record-daemon-transcript-block-projection.md
index ee169121507..dd2e8a033ab 100644
--- a/docs/design/2026-07-14-chat-record-daemon-transcript-block-projection.md
+++ b/docs/design/2026-07-14-chat-record-daemon-transcript-block-projection.md
@@ -353,6 +353,7 @@ The first version stabilizes at least the following diagnostic codes. Codes are
 | malformed_part                  | true                | A recognized malformed part was skipped       |
 | unknown_record_or_part          | true                | An unknown extension may contain visible data |
 | ambiguous_tool_call_correlation | true                | A tool result cannot be correlated uniquely   |
+| missing_tool_result             | true                | A tool call has no persisted result           |
 | presentation_fallback           | false               | Presentation adapter failed; fallback used    |
 | transcript_blocks_truncated     | true                | `maxBlocks` removed older blocks              |
 | transcript_text_truncated       | true                | A text block exceeded the character limit     |
diff --git a/packages/acp-bridge/src/transcript-replay.test.ts b/packages/acp-bridge/src/transcript-replay.test.ts
index 27ae8dff014..937701c940c 100644
--- a/packages/acp-bridge/src/transcript-replay.test.ts
+++ b/packages/acp-bridge/src/transcript-replay.test.ts
@@ -58,7 +58,8 @@ describe('createTranscriptReplayMachine', () => {
   });
 
   it('uses stable synthetic ids and finalizes dangling calls once', () => {
-    const machine = createTranscriptReplayMachine();
+    const onDiagnostic = vi.fn();
+    const machine = createTranscriptReplayMachine({ onDiagnostic });
     const projected = updates(
       machine,
       record('assistant-1', 'assistant', {
@@ -88,6 +89,13 @@ describe('createTranscriptReplayMachine', () => {
         },
       ],
     });
+    expect(onDiagnostic).toHaveBeenCalledWith(
+      expect.objectContaining({
+        code: 'missing_tool_result',
+        affectsCompleteness: true,
+        recordId: 'assistant-1',
+      }),
+    );
     expect([...machine.finalize()]).toEqual([]);
   });
 
diff --git a/packages/acp-bridge/src/transcript-replay.ts b/packages/acp-bridge/src/transcript-replay.ts
index ed099681b57..7f88e93cadb 100644
--- a/packages/acp-bridge/src/transcript-replay.ts
+++ b/packages/acp-bridge/src/transcript-replay.ts
@@ -425,6 +425,11 @@ class DefaultTranscriptReplayMachine implements TranscriptReplayMachine {
     let ordinal = 0;
     for (const pending of [...this.pendingToolCalls.values()]) {
       this.pendingToolCalls.delete(pending.callId);
+      this.report(
+        'missing_tool_result',
+        'A transcript tool call has no persisted result.',
+        pending.sourceRecordId,
+      );
       yield {
         sourceRecordId: pending.sourceRecordId,
         ...(pending.sourceTimestamp
diff --git a/packages/sdk-typescript/test/unit/daemon-transcript-projection.test.ts b/packages/sdk-typescript/test/unit/daemon-transcript-projection.test.ts
index a2a4d1be3cb..171838b6d3c 100644
--- a/packages/sdk-typescript/test/unit/daemon-transcript-projection.test.ts
+++ b/packages/sdk-typescript/test/unit/daemon-transcript-projection.test.ts
@@ -277,7 +277,7 @@ describe('projectChatRecordsToDaemonTranscript', () => {
     expect(projection.complete).toBe(true);
   });
 
-  it('finalizes dangling tools as failed', () => {
+  it('finalizes dangling tools as failed and marks the projection incomplete', () => {
     const projection = projectChatRecordsToDaemonTranscript([
       record('tool-start', null, {
         type: 'assistant',
@@ -293,6 +293,14 @@ describe('projectChatRecordsToDaemonTranscript', () => {
       status: 'failed',
       toolCallId: 'qwen-replay-tool:tool-start:0',
     });
+    expect(projection.complete).toBe(false);
+    expect(projection.diagnostics).toContainEqual(
+      expect.objectContaining({
+        code: 'missing_tool_result',
+        affectsCompleteness: true,
+        recordId: 'tool-start',
+      }),
+    );
   });
 
   it('preserves assistant usage when the record ends with a tool call', () => {