Codex exec does not fire Stop / SessionStop / PostToolUse hooks (only UserPromptSubmit fires) #18607

Summary

In non-interactive mode (codex exec), only the UserPromptSubmit hook fires.
All post-session hooks (Stop, SessionStop, PostToolUse, PreToolUse) are
never invoked. The same hooks configured in ~/.codex/hooks.json fire correctly
in interactive TUI mode.

Environment

• Codex CLI: 0.121.0 (broken)
• Last known working: observed working in some version <= 2026-04-19 (interactive TUI)
• OS: Windows 11 Pro 10.0.26200
• Node: v24.12.0
• npm: 11.7.0
• Install: npm install -g @openai/codex@latest
• Features: codex_hooks = true (confirmed via codex features list)

Reproduction

1. Install Codex and enable hooks:

   npm install -g @openai/codex@latest
   codex features enable codex_hooks
   

2. Create ~/.codex/hooks.json:
   {
   "hooks": {
   "UserPromptSubmit": [{
   "hooks": [{
   "type": "command",
   "command": "node -e "process.stderr.write('HOOK UserPromptSubmit FIRED\n')""
   }]
   }],
   "Stop": [{
   "hooks": [{
   "type": "command",
   "command": "node -e "process.stderr.write('HOOK Stop FIRED\n')""
   }]
   }],
   "SessionStop": [{
   "hooks": [{
   "type": "command",
   "command": "node -e "process.stderr.write('HOOK SessionStop FIRED\n')""
   }]
   }],
   "PostToolUse": [{
   "hooks": [{
   "type": "command",
   "command": "node -e "process.stderr.write('HOOK PostToolUse FIRED\n')""
   }]
   }]
   }
   }
3. Run in non-interactive mode:
   codex exec "Say hi"

Expected

All four hooks (UserPromptSubmit, Stop/SessionStop, PostToolUse) fire.

Actual

Only UserPromptSubmit fires. The Codex output shows:
hook: UserPromptSubmit
hook: UserPromptSubmit Completed
codex
Hi
tokens used
...

No other hook lines appear. Hook scripts are not invoked (verified via
file-level log writes — only UserPromptSubmit produces log entries).

Event names verified present in the Codex binary

Using PowerShell UTF-8 regex scan over codex.exe:
UserPromptSubmit, PreToolUse, PostToolUse, SessionStart,
SessionStop, Notification, Stop, CompactStart
So the events exist as valid hook names, they just aren't emitted in exec mode.

Comparison with interactive mode

The same hooks.json works perfectly when running the interactive TUI
(plain codex, no exec). Session files in ~/.codex/sessions/YYYY/MM/DD/
from interactive runs have "originator":"codex-tui" and "source":"cli"
and the hook log shows Stop firing. Session files from codex exec runs
have "originator":"codex_exec" and "source":"exec" and no Stop fires.

Impact

Any workflow that relies on post-response automation — auto-save to external
memory systems, telemetry, triggering follow-up actions, structured logging —
is broken in codex exec. Users must fall back to manually invoking hooks
from a wrapper script after each codex exec call.

Suggested fix

Either:

• Emit Stop / SessionStop in codex exec after the final response is
  delivered (before process exit), OR
• Document that exec mode intentionally skips session hooks and provide
  a dedicated --post-hook CLI flag for non-interactive use cases.