diff --git a/src/main/__tests__/integration-event-bridge.test.ts b/src/main/__tests__/integration-event-bridge.test.ts
index fcf93981..854f2239 100644
--- a/src/main/__tests__/integration-event-bridge.test.ts
+++ b/src/main/__tests__/integration-event-bridge.test.ts
@@ -960,6 +960,29 @@ test('integration events ignore index, discovery, tmp, dotfile, and local writeb
   assert.deepEqual(harness.listAgentsCalls, [])
 })
 
+test('integration events notify nested non-numeric Slack message records', async () => {
+  const harness = makeHarness()
+
+  await withMockedNow('2026-06-04T21:20:00.000Z', async () => {
+    await harness.bridge.reconcile('project-1', [
+      integration({
+        provider: 'slack',
+        integrationId: 'slack-1',
+        mountPaths: ['/slack/channels/C123ABC'],
+        scope: {
+          notifyAgents: ['alice']
+        }
+      })
+    ])
+
+    await harness.emit(changeEvent('/slack/channels/C123ABC/messages/1780607825_485189/files/attachment.json', 'slack'))
+    await waitForSent(harness, 1)
+  })
+
+  assert.deepEqual(harness.sent.map((message) => message.input.to), ['alice'])
+  assert.equal(harness.sent[0].input.data?.path, '/slack/channels/C123ABC/messages/1780607825_485189/files/attachment.json')
+})
+
 test('integration events ignore agent-originated Relayfile writes', async () => {
   const harness = makeHarness()
 
diff --git a/src/main/integration-event-bridge.ts b/src/main/integration-event-bridge.ts
index 892c3958..59cd771b 100644
--- a/src/main/integration-event-bridge.ts
+++ b/src/main/integration-event-bridge.ts
@@ -1271,11 +1271,12 @@ function shouldNotifyRelayfilePath(pathValue: string): boolean {
 function isLikelyLocalWritebackCommandPath(path: string): boolean {
   const segments = pathSegments(path)
   const leaf = segments.at(-1) || ''
+  const parent = segments.at(-2)
   const stem = leaf.replace(/\.json$/u, '')
   const provider = segments[0]
   if (provider !== 'slack' && provider !== 'chat') return false
   if (!leaf.endsWith('.json') || leaf === 'meta.json') return false
-  if (!segments.some((segment) => segment === 'messages' || segment === 'replies')) return false
+  if (parent !== 'messages' && parent !== 'replies') return false
   return !/^\d+(?:[._-]\d+)*$/u.test(stem)
 }