Merge a87796d596178b271082c1d8743ef4dfdb95707e into 5e417b44e1540f528d2ae63e3e20229a902d1db2

extensions/discord/src/monitor/message-handler.preflight.ts

@@ -791,7 +791,7 @@ export async function preflightDiscordMessage(
     `[discord-preflight] shouldRequireMention=${shouldRequireMention} baseRequireMention=${shouldRequireMentionByConfig} boundThreadSession=${isBoundThreadSession} mentionGate.shouldSkip=${mentionGate.shouldSkip} wasMentioned=${wasMentioned}`,
   );
   if (isGuildMessage && shouldRequireMention) {
-    if (botId && mentionGate.shouldSkip) {
+    if (mentionGate.shouldSkip) {
       logDebug(`[discord-preflight] drop: no-mention`);
       logVerbose(`discord: drop guild message (mention required, botId=${botId})`);
       logger.info(

extensions/discord/src/monitor/provider.test.ts

@@ -627,4 +627,36 @@ describe("monitorDiscordProvider", () => {
     const messages = vi.mocked(runtime.log).mock.calls.map((call) => String(call[0]));
     expect(messages.some((msg) => msg.includes("discord startup ["))).toBe(false);
   });
+
+  it("falls back to applicationId when fetchUser('@me') fails (#42219)", async () => {
+    const { monitorDiscordProvider } = await import("./provider.js");
+    const runtime = baseRuntime();
+
+    clientFetchUserMock.mockRejectedValueOnce(new Error("network timeout"));
+
+    // Should NOT throw — the code now falls back to applicationId as botUserId
+    // instead of aborting. We race with a short timeout to confirm no immediate rejection.
+    const result = await Promise.race([
+      monitorDiscordProvider({
+        config: baseConfig(),
+        runtime,
+      }).then(() => "resolved", (err: Error) => `rejected: ${err.message}`),
+      new Promise<string>((r) => setTimeout(() => r("still-running"), 200)),
+    ]);
+    expect(result).toBe("still-running");
+  });
+
+  it("throws when fetchUser('@me') returns no user id", async () => {
+    const { monitorDiscordProvider } = await import("./provider.js");
+    const runtime = baseRuntime();
+
+    clientFetchUserMock.mockResolvedValueOnce({ id: undefined as unknown as string, username: "NoId" });
+
+    await expect(
+      monitorDiscordProvider({
+        config: baseConfig(),
+        runtime,
+      }),
+    ).rejects.toThrow("discord: fetchUser('@me') returned no user id");
+  });
 });

extensions/discord/src/monitor/provider.ts

@@ -882,6 +882,20 @@ export async function monitorDiscordProvider(opts: MonitorDiscordOpts = {}) {
         gateway: lifecycleGateway,
         details: String(err),
       });
+      // Transient REST/proxy failures should not take down the whole channel.
+      // applicationId is the same snowflake as the bot user id and was already
+      // resolved above (with a token-decoding fallback), so we can use it for
+      // mention gating and self-message filtering. botUserName is only used for
+      // logging and is non-critical.
+      botUserId = applicationId;
+      runtime.warn?.(
+        `discord: using applicationId as botUserId fallback (fetchUser failed: ${String(err)})`,
+      );
+    }
+    if (!botUserId) {
+      // fetchUser succeeded but returned no id and applicationId is also missing —
+      // this should not happen in practice.
+      throw new Error("discord: fetchUser('@me') returned no user id");
     }
 
     if (voiceEnabled) {