diff --git a/packages/core/src/services/chatRecordingService.test.ts b/packages/core/src/services/chatRecordingService.test.ts
index 0d5bb7ef1..0459e93df 100644
--- a/packages/core/src/services/chatRecordingService.test.ts
+++ b/packages/core/src/services/chatRecordingService.test.ts
@@ -505,6 +505,37 @@ describe('ChatRecordingService', () => {
         afterFailure + 1,
       );
     });
+
+    // appendRecord can throw SYNCHRONOUSLY before returning a promise
+    // (e.g. ensureConversationFile fails because the conversation
+    // file can't be created). Without rollback in the outer catch,
+    // the dedup key stays set on a write that never happened, so
+    // all future identical snapshots get suppressed.
+    it('should retry an identical snapshot after a synchronous failure', async () => {
+      // First call: force writeFileSync (used by ensureConversationFile
+      // to wx-create the JSONL file) to throw a non-EEXIST error.
+      // ensureConversationFile rethrows that, which propagates through
+      // appendRecord SYNCHRONOUSLY before any promise is returned.
+      const writeFileSpy = vi.spyOn(fs, 'writeFileSync');
+      writeFileSpy.mockImplementationOnce(() => {
+        const e = new Error(
+          'EACCES: permission denied',
+        ) as NodeJS.ErrnoException;
+        e.code = 'EACCES';
+        throw e;
+      });
+
+      chatRecordingService.recordAttributionSnapshot(baseSnapshot);
+      await chatRecordingService.flush();
+      // Sync failure: writeLine never reached.
+      expect(vi.mocked(jsonl.writeLine)).not.toHaveBeenCalled();
+
+      // Identical snapshot on retry: dedup key should have been
+      // rolled back so this fires a fresh write.
+      chatRecordingService.recordAttributionSnapshot(baseSnapshot);
+      await chatRecordingService.flush();
+      expect(vi.mocked(jsonl.writeLine)).toHaveBeenCalledTimes(1);
+    });
   });
 
   // Note: Session management tests (listSessions, loadSession, deleteSession, etc.)
diff --git a/packages/core/src/services/chatRecordingService.ts b/packages/core/src/services/chatRecordingService.ts
index dd6718ed2..2490b9bc6 100644
--- a/packages/core/src/services/chatRecordingService.ts
+++ b/packages/core/src/services/chatRecordingService.ts
@@ -1007,8 +1007,9 @@ export class ChatRecordingService {
    * than being permanently suppressed.
    */
   recordAttributionSnapshot(snapshot: AttributionSnapshot): void {
+    let json: string | undefined;
     try {
-      const json = JSON.stringify(snapshot);
+      json = JSON.stringify(snapshot);
       if (json === this.lastAttributionSnapshotJson) {
         return;
       }
@@ -1021,13 +1022,24 @@ export class ChatRecordingService {
 
       this.lastAttributionSnapshotJson = json;
       this.appendRecord(record).catch(() => {
-        // Write failed — only roll back if the key still belongs to
-        // our snapshot (a later distinct write may have overwritten it).
+        // Async write failed — only roll back if the key still
+        // belongs to our snapshot (a later distinct write may have
+        // overwritten it).
         if (this.lastAttributionSnapshotJson === json) {
           this.lastAttributionSnapshotJson = undefined;
         }
       });
     } catch (error) {
+      // appendRecord (and createBaseRecord/JSON.stringify) can throw
+      // synchronously — e.g. ensureConversationFile() fails because
+      // the project temp dir isn't writable. The .catch() handler
+      // attached to the promise never runs in that case, so we'd
+      // otherwise leave the dedup key set without a write ever
+      // having landed and permanently suppress identical retries.
+      // Roll back here too.
+      if (json !== undefined && this.lastAttributionSnapshotJson === json) {
+        this.lastAttributionSnapshotJson = undefined;
+      }
       debugLogger.error('Error saving attribution snapshot:', error);
     }
   }