Fixes https://github.com/openai/codex/issues/16732.
## Why
`apply_patch` is Codex's primary file edit path, but it was not emitting
`PreToolUse` or `PostToolUse` hook events. That meant hook-based policy,
auditing, and write coordination could observe shell commands while
missing the actual file mutation performed by `apply_patch`.
The issue also exposed that the hook runtime serialized command hook
payloads with `tool_name: "Bash"` unconditionally. Even if `apply_patch`
supplied hook payloads, hooks would either fail to match it directly or
receive misleading stdin that identified the edit as a Bash tool call.
## What Changed
- Added `PreToolUse` and `PostToolUse` payload support to
`ApplyPatchHandler`.
- Exposed the raw patch body as `tool_input.command` for both
JSON/function and freeform `apply_patch` calls.
- Taught tool hook payloads to carry a handler-supplied hook-facing
`tool_name`.
- Preserved existing shell compatibility by continuing to emit `Bash`
for shell-like tools.
- Serialized the selected hook `tool_name` into hook stdin instead of
hardcoding `Bash`.
- Relaxed the generated hook command input schema so `tool_name` can
represent tools other than `Bash`.
## Verification
Added focused handler coverage for:
- JSON/function `apply_patch` calls producing a `PreToolUse` payload.
- Freeform `apply_patch` calls producing a `PreToolUse` payload.
- Successful `apply_patch` output producing a `PostToolUse` payload.
- Shell and `exec_command` handlers continuing to expose `Bash`.
Added end-to-end hook coverage for:
- A `PreToolUse` hook matching `^apply_patch$` blocking the patch before
the target file is created.
- A `PostToolUse` hook matching `^apply_patch$` receiving the patch
input and tool response, then adding context to the follow-up model
request.
- Non-participating tools such as the plan tool continuing not to emit
`PreToolUse`/`PostToolUse` hook events.
Also validated manually with a live `codex exec` smoke test using an
isolated temp workspace and temp `CODEX_HOME`. The smoke test confirmed
that a real `apply_patch` edit emits `PreToolUse`/`PostToolUse` with
`tool_name: "apply_patch"`, a shell command still emits `tool_name:
"Bash"`, and a denying `PreToolUse` hook prevents the blocked patch file
from being created.
- add `PreToolUse` hook for bash-like tool execution only at first
- block shell execution before dispatch with deny-only hook behavior
- introduces common.rs matcher framework for matching when hooks are run
example run:
```
› run three parallel echo commands, and the second one should echo "[block-pre-tool-use]" as a test
• Running the three echo commands in parallel now and I’ll report the output directly.
• Running PreToolUse hook: name for demo pre tool use hook
• Running PreToolUse hook: name for demo pre tool use hook
• Running PreToolUse hook: name for demo pre tool use hook
PreToolUse hook (completed)
warning: wizard-tower PreToolUse demo inspected Bash: echo "first parallel echo"
PreToolUse hook (blocked)
warning: wizard-tower PreToolUse demo blocked a Bash command on purpose.
feedback: PreToolUse demo blocked the command. Remove [block-pre-tool-use] to continue.
PreToolUse hook (completed)
warning: wizard-tower PreToolUse demo inspected Bash: echo "third parallel echo"
• Ran echo "first parallel echo"
└ first parallel echo
• Ran echo "third parallel echo"
└ third parallel echo
• Three little waves went out in parallel.
1. printed first parallel echo
2. was blocked before execution because it contained the exact test string [block-pre-tool-use]
3. printed third parallel echo
There was also an unrelated macOS defaults warning around the successful commands, but the echoes
themselves worked fine. If you want, I can rerun the second one with a slightly modified string so
it passes cleanly.
```
Felipe Coury ·
Andrei Eternal ·