fix: clear tlon SSE connect timeout (#5926) (thanks @hclsys)

Add timeout protection to prevent indefinite hangs when Urbit server
becomes unresponsive or network partition occurs.

Changes:
- Add AbortSignal.timeout(30_000) to 7 one-shot fetch calls
- Add AbortController with 60s connection timeout to SSE stream fetch
  (clears timeout after headers received to avoid aborting active stream)

Affected methods: sendSubscription, connect, openStream, poke, scry, close

Fixes #5266

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -25,6 +25,7 @@ Docs: https://docs.openclaw.ai
 - Telegram: restore draft streaming partials. (#5543) Thanks @obviyus.
 - Onboarding: friendlier Windows onboarding message. (#6242) Thanks @shanselman.
 - TUI: prevent crash when searching with digits in the model selector.
+- Tlon: clear SSE connection timeout on failed connect. (#5926) Thanks @hclsys.
 - Agents: wire before_tool_call plugin hook into tool execution. (#6570) Thanks @ryancnelson.
 - Browser: secure Chrome extension relay CDP sessions.
 - Docker: use container port for gateway command instead of host port. (#5110) Thanks @mise42.

extensions/tlon/src/urbit/sse-client.test.ts

@@ -37,4 +37,23 @@ describe("UrbitSSEClient", () => {
       path: "/dm/~zod",
     });
   });
+
+  it("clears the connection timeout when fetch fails", async () => {
+    const timeoutId = 123 as unknown as NodeJS.Timeout;
+    const setTimeoutSpy = vi.spyOn(global, "setTimeout").mockReturnValue(timeoutId);
+    const clearTimeoutSpy = vi.spyOn(global, "clearTimeout");
+
+    mockFetch.mockRejectedValue(new Error("network down"));
+
+    const client = new UrbitSSEClient("https://example.com", "urbauth-~zod=123");
+
+    try {
+      await expect(client.openStream()).rejects.toThrow("network down");
+      expect(setTimeoutSpy).toHaveBeenCalled();
+      expect(clearTimeoutSpy).toHaveBeenCalledWith(timeoutId);
+    } finally {
+      setTimeoutSpy.mockRestore();
+      clearTimeoutSpy.mockRestore();
+    }
+  });
 });

extensions/tlon/src/urbit/sse-client.ts

@@ -114,6 +114,7 @@ export class UrbitSSEClient {
         Cookie: this.cookie,
       },
       body: JSON.stringify([subscription]),
+      signal: AbortSignal.timeout(30_000),
     });
 
     if (!response.ok && response.status !== 204) {
@@ -130,6 +131,7 @@ export class UrbitSSEClient {
         Cookie: this.cookie,
       },
       body: JSON.stringify(this.subscriptions),
+      signal: AbortSignal.timeout(30_000),
     });
 
     if (!createResp.ok && createResp.status !== 204) {
@@ -152,6 +154,7 @@ export class UrbitSSEClient {
           json: "Opening API channel",
         },
       ]),
+      signal: AbortSignal.timeout(30_000),
     });
 
     if (!pokeResp.ok && pokeResp.status !== 204) {
@@ -164,12 +167,21 @@ export class UrbitSSEClient {
   }
 
   async openStream() {
+    // Use AbortController with manual timeout so we only abort during initial connection,
+    // not after the SSE stream is established and actively streaming.
+    const controller = new AbortController();
+    const timeoutId = setTimeout(() => controller.abort(), 60_000);
+
     const response = await fetch(this.channelUrl, {
       method: "GET",
       headers: {
         Accept: "text/event-stream",
         Cookie: this.cookie,
       },
+      signal: controller.signal,
+    }).finally(() => {
+      // Clear timeout once connection established (headers received) or on failure.
+      clearTimeout(timeoutId);
     });
 
     if (!response.ok) {
@@ -279,6 +291,7 @@ export class UrbitSSEClient {
         Cookie: this.cookie,
       },
       body: JSON.stringify([pokeData]),
+      signal: AbortSignal.timeout(30_000),
     });
 
     if (!response.ok && response.status !== 204) {
@@ -296,6 +309,7 @@ export class UrbitSSEClient {
       headers: {
         Cookie: this.cookie,
       },
+      signal: AbortSignal.timeout(30_000),
     });
 
     if (!response.ok) {
@@ -364,6 +378,7 @@ export class UrbitSSEClient {
           Cookie: this.cookie,
         },
         body: JSON.stringify(unsubscribes),
+        signal: AbortSignal.timeout(30_000),
       });
 
       await fetch(this.channelUrl, {
@@ -371,6 +386,7 @@ export class UrbitSSEClient {
         headers: {
           Cookie: this.cookie,
         },
+        signal: AbortSignal.timeout(30_000),
       });
     } catch (error) {
       this.logger.error?.(`Error closing channel: ${String(error)}`);