[BUG] UserPromptSubmit hook exits non-zero with no stderr when worker health check fails (missing `|| true`)

[mikelkew]

Before submitting

• I searched existing issues and confirmed this is not a duplicate

Related but not duplicates:

• SessionStart hook fails silently with 'No stderr output' when worker health check times out #1794 (closed) — "SessionStart hook fails silently with 'No stderr output' when worker health check times out". Same failure mode, different hook. The fix there did not reach the UserPromptSubmit branch.
• [BUG] Linux/WSL UserPromptSubmit runs session-init before worker is healthy #1907 (closed) — "Linux/WSL UserPromptSubmit runs session-init before worker is healthy". Related, platform-specific.
• Worker startup race condition causes 2 SessionStart hook errors on every first session #1447 (closed), [BUG] SessionStart health-check curl uses hardcoded port 37777 #1898 (open) — adjacent health-check / port issues.

---

📝 Manual Bug Report

Bug Description

The UserPromptSubmit hook defined in plugin/hooks/hooks.json can exit with a non-zero status and zero bytes of stderr, producing the Claude Code error:

UserPromptSubmit hook error — Failed with non-blocking status code: No stderr output

The cause is in the shell command itself. The final step is:

[ "$_HEALTH" = "1" ] && node "$_R/scripts/bun-runner.js" "$_R/scripts/worker-service.cjs" hook claude-code session-init

There is no trailing || true. So whenever the worker's /health endpoint is not reachable within the 10×1s retry budget (worker restarting, cold start, transiently unhealthy, port mismatch, etc.), [ "$_HEALTH" = "1" ] evaluates to false, the whole shell command exits with status 1, and nothing is written to stderr. Claude Code surfaces it as the "No stderr output" error above.

Comparable branches in the same file (e.g. SessionStart session-init, which was hardened in #1794 via adding a || true / defensive echo ... || true) already guard against this. The UserPromptSubmit branch was not updated.

Checked all cached versions on the reporter's machine (12.1.5, 12.1.6, 12.2.0, 12.3.2, 12.3.7, 12.3.8, 12.3.9) and the command tail is byte-identical — the missing || true has been present since at least 12.1.5. The latest main on GitHub is also still affected.

Steps to Reproduce

1. Install or run claude-mem@12.3.9 in Claude Code.
2. Stop the worker (pkill -f worker-service.cjs) or otherwise make http://$HOST:$PORT/health unreachable.
3. Submit any prompt.
4. Claude Code shows: UserPromptSubmit hook error — Failed with non-blocking status code: No stderr output.

It also reproduces intermittently in normal use (right at session start, after a crash, or when the worker is briefly busy enough to miss the 10-second retry budget).

Expected Behavior

When the worker is unreachable, the hook should exit 0 silently — the same contract the SessionStart session-init branch now uses. The end user should never see a non-zero status from this hook just because the worker had not yet come up.

Proposed Fix

Append || true (or equivalent) to the UserPromptSubmit command in plugin/hooks/hooks.json. For example:

- … [ "$_HEALTH" = "1" ] && node "$_R/scripts/bun-runner.js" "$_R/scripts/worker-service.cjs" hook claude-code session-init
+ … [ "$_HEALTH" = "1" ] && node "$_R/scripts/bun-runner.js" "$_R/scripts/worker-service.cjs" hook claude-code session-init || true

A stricter variant that keeps the "only run node when healthy" guard but never leaks a non-zero exit:

if [ "$_HEALTH" = "1" ]; then
  node "$_R/scripts/bun-runner.js" "$_R/scripts/worker-service.cjs" hook claude-code session-init || true
fi
exit 0

Either way, the hook should match the graceful-degradation already applied to SessionStart in #1794.

Environment

• Claude-mem version: 12.3.9 (latest, released 2026-04-22)
• Claude Code version: 2.1.118
• OS: macOS Darwin arm64
• Platform: Claude Code (desktop/CLI)
• Node: v24.14.1

Logs

Worker health confirmed functional when captured:

$ curl -sf http://127.0.0.1:<port>/health
{"status":"ok","timestamp":<ts>,"activeSessions":2}
EXIT=0

When the worker is up, the hook's own session-init runs cleanly and returns {} with exit 0:

$ _R="~/.claude/plugins/cache/thedotmack/claude-mem/12.3.9"
$ node "$_R/scripts/bun-runner.js" "$_R/scripts/worker-service.cjs" hook claude-code session-init
{}
EXIT=0

The failure is entirely in the outer shell command when _HEALTH=0 — no log entry is produced because nothing inside the node handler is reached.

One related WARN observed in ~/.claude-mem/logs/claude-mem-YYYY-MM-DD.log (may or may not relate):

[WARN ] [HOOK  ] session-init: No sessionId provided, skipping (Codex CLI or unknown platform)

This path already returns {continue:true, suppressOutput:true, exitCode: SUCCESS} in the handler, so it does not cause the shell-level non-zero exit.

Additional Context

The identical pattern exists in the SessionStart hook chain in older releases and was historically noisy; it was fixed by adding || true-style guards (see #1794, #1447). Applying the same fix to the UserPromptSubmit command closes the last remaining path that surfaces "No stderr output" to end users.

[github-actions]

The GitHub issue reports a bug in the UserPromptSubmit hook of the claude-mem plugin, where the shell command responsible for initiating the hook session exits with a non-zero status but provides no stderr output when a worker health check fails. This results in a misleading error message in Claude Code: "No stderr output." The issue stems from a missing || true in the shell command, which causes unhandled failures when the worker’s health endpoint is unreachable within the retry limit, such as during restarts, cold starts, or other transient issues. The behavior affects all versions since 12.1.5 and matches an earlier fixed issue (#1794) for the SessionStart hook, suggesting the fix didn’t propagate to this hook. The proposed solution is to append || true to the shell command or adopt a stricter approach to ensure graceful handling of health check failures, consistent with prior fixes in other parts of the codebase. This change

[mikelkew]

I couldn't open a PR directly — this repo appears to restrict PR creation to the maintainer (all recent PRs are @thedotmack's own; gh pr create returns permissions/404 from a fork branch).

I've pushed the one-line fix to a branch on my fork. Comparison view:

• main...mikelkew:claude-mem:fix/user-prompt-submit-silent-exit
• Branch: mikelkew:fix/user-prompt-submit-silent-exit
• Single commit (GPG-signed): fix(hooks): Guard UserPromptSubmit shell exit code

Diff

diff --git a/plugin/hooks/hooks.json b/plugin/hooks/hooks.json
--- a/plugin/hooks/hooks.json
+++ b/plugin/hooks/hooks.json
@@ UserPromptSubmit @@
-… [ "$_HEALTH" = "1" ] && node "$_R/scripts/bun-runner.js" "$_R/scripts/worker-service.cjs" hook claude-code session-init
+… [ "$_HEALTH" = "1" ] && node "$_R/scripts/bun-runner.js" "$_R/scripts/worker-service.cjs" hook claude-code session-init || true

Behaviour matrix:

State	Before	After
Worker healthy, node succeeds	exit 0	exit 0
Worker healthy, node fails	exit ≠0, noisy	exit 0, silent
Worker unhealthy	exit 1, silent	exit 0, silent

Happy to rebase or restructure if you'd prefer a different shape (e.g. an if [ ... ]; then ...; fi; exit 0 block, matching the SessionStart context-inject branch more literally). Just let me know.