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SessionEnd hook hangs when broker is unresponsive (missing timeout in sendBrokerShutdown) #245
Closed as duplicate
Description
Bug
The SessionEnd hook (scripts/session-lifecycle-hook.mjs) hangs and gets cancelled by Claude Code when the broker process is unresponsive.
Error message:
SessionEnd hook [node "${CLAUDE_PLUGIN_ROOT}/scripts/session-lifecycle-hook.mjs" SessionEnd] failed: Hook cancelled
Root Cause
sendBrokerShutdown() in scripts/lib/broker-lifecycle.mjs:43-57 creates a socket connection and waits for a data event after sending the shutdown message, but has no timeout:
export async function sendBrokerShutdown(endpoint) {
await new Promise((resolve) => {
const socket = connectToEndpoint(endpoint);
socket.setEncoding("utf8");
socket.on("connect", () => {
socket.write(`${JSON.stringify({ id: 1, method: "broker/shutdown", params: {} })}\n`);
});
socket.on("data", () => {
socket.end();
resolve();
});
socket.on("error", resolve);
socket.on("close", resolve);
});
}If the broker process:
- Has the socket file present but is hung/zombie →
connectsucceeds,datanever fires - Is slow to respond → Promise waits indefinitely
Claude Code's hook timeout eventually fires and kills the hook with "Hook cancelled".
Note: waitForBrokerEndpoint() at line 24 correctly has a timeoutMs = 2000 parameter. The shutdown call does not.
Suggested Fix
Add a timeout to the shutdown Promise:
export async function sendBrokerShutdown(endpoint) {
await new Promise((resolve) => {
const socket = connectToEndpoint(endpoint);
const timeout = setTimeout(() => {
socket.destroy();
resolve();
}, 3000); // 3s timeout — broker should respond quickly to shutdown
socket.setEncoding("utf8");
socket.on("connect", () => {
socket.write(`${JSON.stringify({ id: 1, method: "broker/shutdown", params: {} })}\n`);
});
socket.on("data", () => {
clearTimeout(timeout);
socket.end();
resolve();
});
socket.on("error", () => { clearTimeout(timeout); resolve(); });
socket.on("close", () => { clearTimeout(timeout); resolve(); });
});
}Environment
- Claude Code CLI (macOS arm64, Darwin 25.3.0)
- Plugin version: codex 1.0.1 (from
openai-codexmarketplace) - Reproduction: use Codex companion during a session, then exit. If broker becomes unresponsive between session and shutdown, the SessionEnd hook hangs.
Impact
Non-blocking (session ends normally), but produces a confusing error message on every affected session exit. Users may think their session data was lost.
Activity
fix(claude): bump SessionEnd hook timeout to avoid /exit cancel regre…
pandalaohe commentedon Apr 30, 2026
Hit this on Windows during a Claude Code + custom hooks integration. The
Hook cancelledmessage appears intermittently after Codex review sessions when the broker becomes unresponsive between session and shutdown.Local mitigation: registered the plugin's
SessionEndhook explicitly in~/.claude/settings.jsonwithtimeout: 30(the upstreamplugins/codex/hooks/hooks.jsondeclaration didn't auto-merge into our active hook list, so cleanup was never running). That gets the outer 30s budget, but the underlying issue is still thatsendBrokerShutdownitself never times out — the 30s is just CC's outer kill, not graceful.The suggested 3s socket-level timeout fix in the issue body matches what we'd expect. Happy to test it against our reproduction setup if a PR materializes.
(Adding a +1 / data-point in case it helps prioritize.)
axisrow commentedon Jul 16, 2026
Same class as #288 — scenario 2 in the #163 map: the
SessionEndhook hangs on an unresponsive broker becausesendBrokerShutdownhas no timeout. Out of scope for PR #490 (the timer lives inside the broker, the hang is client-side). The fix is a client-side bounded timeout. See #163.yuanchen8911 commentedon Aug 10, 2026
Cross-reference: #612 and PR #623 make shutdown fail closed on ambiguous outcomes, but intentionally leave the accepted-and-never-replies timeout out of scope. This issue remains the tracker for bounding that exchange and destroying the socket within the SessionEnd hook budget. Duplicate report: #288.
dkundel-openai commentedon Aug 11, 2026
Duplicate of #288.