[alexb-openrouter]

Summary

Risk fixed: a PreToolUse deny guard could be silently skipped, and the tool ran anyway. If an earlier handler returned detached work ({ async: true, work, asyncTimeout }) and that work hit its timeout while a later handler was still running, the emit signal was aborted, executeHandlerChain stopped before the remaining handlers, and the emit returned blocked: false. The tool executor reads blocked: false as "allowed", so a guard that would have returned { block } never ran. abortInflight() mid-chain had the same effect.

Change: in executeHandlerChain, when the chain bails out on context.signal.aborted and the hook has a blockField (PreToolUse → block, UserPromptSubmit → reject), set blocked = true:

if (context.signal.aborted) {
  if (behavior?.blockField) blocked = true; // fail closed: unrun handlers may include the guard
  break;
}

The tool call then gets the existing hook_blocked result ("Blocked by PreToolUse hook"), and UserPromptSubmit throws "Prompt rejected by hook". Non-blocking hooks (PostToolUse, etc.) are unchanged: an aborted chain still just stops.

Tests: new cases in hooks-contract-fixes.test.ts. The detached-timeout-skips-guard case and the abortInflight()-mid-chain case both fail on main (blocked: false) and pass with this change. Controls check that a timeout that settles in time still runs every handler, and that non-blocking hooks are not marked blocked. Full unit suite, biome and typecheck pass.

Note: open PR #107 also touches hooks-emit.ts (handler return validation). These changes don't overlap, but one PR may need a small rebase after the other merges.

[devin-ai-integration]

I'll fix CI failures and address comments from users with write access that start with 'Devin'.

• Disable automatic comment, CI, and merge conflict monitoring