diff --git a/src/gateway/server.impl.ts b/src/gateway/server.impl.ts
index 4c29ce17071..e74b1fb69d9 100644
--- a/src/gateway/server.impl.ts
+++ b/src/gateway/server.impl.ts
@@ -967,6 +967,7 @@ export async function startGatewayServer(
                 lastChannel: sessionRow.lastChannel,
                 lastTo: sessionRow.lastTo,
                 lastAccountId: sessionRow.lastAccountId,
+                lastThreadId: sessionRow.lastThreadId,
                 totalTokens: sessionRow.totalTokens,
                 totalTokensFresh: sessionRow.totalTokensFresh,
                 contextTokens: sessionRow.contextTokens,
@@ -1062,6 +1063,7 @@ export async function startGatewayServer(
                     lastChannel: sessionRow.lastChannel,
                     lastTo: sessionRow.lastTo,
                     lastAccountId: sessionRow.lastAccountId,
+                    lastThreadId: sessionRow.lastThreadId,
                     totalTokens: sessionRow.totalTokens,
                     totalTokensFresh: sessionRow.totalTokensFresh,
                     contextTokens: sessionRow.contextTokens,
diff --git a/src/gateway/session-message-events.test.ts b/src/gateway/session-message-events.test.ts
index 89856254651..2269207d1b1 100644
--- a/src/gateway/session-message-events.test.ts
+++ b/src/gateway/session-message-events.test.ts
@@ -385,6 +385,84 @@ describe("session.message websocket events", () => {
     }
   });
 
+  test("includes route thread metadata on session.message and sessions.changed transcript events", async () => {
+    const storePath = await createSessionStoreFile();
+    const transcriptPath = path.join(path.dirname(storePath), "sess-thread.jsonl");
+    await writeSessionStore({
+      entries: {
+        main: {
+          sessionId: "sess-thread",
+          sessionFile: transcriptPath,
+          updatedAt: Date.now(),
+          lastChannel: "telegram",
+          lastTo: "-100123",
+          lastAccountId: "acct-1",
+          lastThreadId: 42,
+        },
+      },
+      storePath,
+    });
+    const transcriptMessage = {
+      role: "assistant",
+      content: [{ type: "text", text: "thread route snapshot" }],
+      timestamp: Date.now(),
+    };
+    await fs.writeFile(
+      transcriptPath,
+      [
+        JSON.stringify({ type: "session", version: 1, id: "sess-thread" }),
+        JSON.stringify({ id: "msg-thread", message: transcriptMessage }),
+      ].join("\n"),
+      "utf-8",
+    );
+
+    const harness = await createGatewaySuiteHarness();
+    try {
+      await withOperatorSessionSubscriber(harness, async (ws) => {
+        const messageEventPromise = waitForSessionMessageEvent(ws, "agent:main:main");
+        const changedEventPromise = onceMessage(
+          ws,
+          (message) =>
+            message.type === "event" &&
+            message.event === "sessions.changed" &&
+            (message.payload as { phase?: string; sessionKey?: string } | undefined)?.phase ===
+              "message" &&
+            (message.payload as { sessionKey?: string } | undefined)?.sessionKey ===
+              "agent:main:main",
+        );
+
+        emitSessionTranscriptUpdate({
+          sessionFile: transcriptPath,
+          sessionKey: "agent:main:main",
+          message: transcriptMessage,
+          messageId: "msg-thread",
+        });
+
+        const [messageEvent, changedEvent] = await Promise.all([
+          messageEventPromise,
+          changedEventPromise,
+        ]);
+        expect(messageEvent.payload).toMatchObject({
+          sessionKey: "agent:main:main",
+          lastChannel: "telegram",
+          lastTo: "-100123",
+          lastAccountId: "acct-1",
+          lastThreadId: 42,
+        });
+        expect(changedEvent.payload).toMatchObject({
+          sessionKey: "agent:main:main",
+          phase: "message",
+          lastChannel: "telegram",
+          lastTo: "-100123",
+          lastAccountId: "acct-1",
+          lastThreadId: 42,
+        });
+      });
+    } finally {
+      await harness.close();
+    }
+  });
+
   test("sessions.messages.subscribe only delivers transcript events for the requested session", async () => {
     const storePath = await createSessionStoreFile();
     await writeSessionStore({