fix(ai): relax Codex SSE header timeout

packages/ai/CHANGELOG.md

@@ -6,6 +6,7 @@
 
 ### Fixed
 
+- Increased the OpenAI Codex Responses SSE response-header timeout to 20 seconds to reduce false-positive stalls while retaining the bounded wait introduced for zero-event hangs ([#4945](https://github.com/earendil-works/pi/issues/4945)).
 - Fixed Claude Fable 5 thinking-off requests to omit Anthropic's unsupported `thinking.type: "disabled"` payload ([#5567](https://github.com/earendil-works/pi/pull/5567) by [@tmustier](https://github.com/tmustier)).
 
 ## [0.79.1] - 2026-06-09

packages/ai/src/providers/openai-codex-responses.ts

@@ -53,7 +53,9 @@ const JWT_CLAIM_PATH = "https://api.openai.com/auth" as const;
 const DEFAULT_MAX_RETRIES = 0;
 const BASE_DELAY_MS = 1000;
 const DEFAULT_MAX_RETRY_DELAY_MS = 60_000;
-const DEFAULT_SSE_HEADER_TIMEOUT_MS = 10_000;
+// Keep a bounded pre-header timeout so zero-event Codex SSE stalls fail instead of
+// leaving callers stuck on "Working..." indefinitely. See #4945.
+const DEFAULT_SSE_HEADER_TIMEOUT_MS = 20_000;
 const DEFAULT_WEBSOCKET_CONNECT_TIMEOUT_MS = 15_000;
 const CODEX_TOOL_CALL_PROVIDERS = new Set(["openai", "openai-codex", "opencode"]);
 const WEBSOCKET_MESSAGE_TOO_BIG_CLOSE_CODE = 1009;

packages/ai/test/openai-codex-stream.test.ts

@@ -361,13 +361,21 @@ describe("openai-codex streaming", () => {
 			apiKey: token,
 			transport: "sse",
 		}).result();
+		let settled = false;
+		const observedResultPromise = resultPromise.then((result) => {
+			settled = true;
+			return result;
+		});
 		await vi.advanceTimersByTimeAsync(0);
 		expect(fetchMock).toHaveBeenCalledTimes(1);
 
 		await vi.advanceTimersByTimeAsync(10_000);
-		const result = await resultPromise;
+		expect(settled).toBe(false);
+
+		await vi.advanceTimersByTimeAsync(10_000);
+		const result = await observedResultPromise;
 		expect(result.stopReason).toBe("error");
-		expect(result.errorMessage).toBe("Codex SSE response headers timed out after 10000ms");
+		expect(result.errorMessage).toBe("Codex SSE response headers timed out after 20000ms");
 	});
 
 	it("aborts SSE body reads after response headers arrive", async () => {