scaffold-codex-hooks
Audit the target project first, then scaffold Codex hooks with a deterministic managed layout around the current official hook model.
Decision Tree
What is the user asking for?
- New project-local Codex hooks in a repo with no hook setup yet: Verify the live official docs and schemas, audit the repo, inspect the effective feature flag, enable it if needed, then scaffold.
- Existing
.codex/hooks.json,.codex/config.toml, or.codex/hooks/files: Audit what exists first, chooseadditiveoroverhaul, then refresh only the managed hook layer. - Hooks that exist on disk but never seem to affect Codex: Inspect the effective
codex_hooksfeature first. If it is still off, enable it deliberately. If it is on, remember that repo-local.codex/config.tomlonly loads in trusted projects, then debughooks.json. - Explanation only, not implementation: Read
references/hook-events.md,references/feature-flag.md, andreferences/scaffold-layout.md, then answer without scaffolding.
Quick Reference
| Task | Action |
|---|---|
| Verify the current official Codex hook model | Read https://developers.openai.com/codex/hooks, https://developers.openai.com/codex/config-basic, and the generated schemas listed in assets/hook-events.json |
| Audit a target repo | Run scripts/audit_project.sh /path/to/project |
Inspect the effective codex_hooks feature | Run python3 scripts/check_hooks_feature.py --project /path/to/project --json |
| Enable hooks in project config | Run python3 scripts/check_hooks_feature.py --project /path/to/project --enable --scope project |
| Enable hooks in user config | Run python3 scripts/check_hooks_feature.py --project /path/to/project --enable --scope user |
| Understand the current event catalog | Read references/hook-events.md |
| Decide additive vs overhaul | Read references/merge-strategy.md |
| Generate or refresh the managed hook scaffold | Run `scripts/scaffold_hooks.sh --project /path/to/project --plan /path/to/plan.json --mode additive |
Merge generated handlers into .codex/hooks.json | Let scripts/scaffold_hooks.sh call scripts/merge_hooks_json.sh, or run the merge script directly |
| Regenerate the hooks README in a target project | Run scripts/render_hooks_readme.sh --project /path/to/project --plan /path/to/plan.json |
Non-Negotiable Workflow
- Verify the live official Codex hook docs before planning any scaffold.
- Compare the live docs, current schemas, and
assets/hook-events.jsonbefore assuming the event set or output contract is unchanged. - Audit the target project in detail before deciding which events to enable or which commands to run.
- Inspect the effective
codex_hooksfeature in the target project before treating any repo-localhooks.jsonas active. - If the feature is off, enable it deliberately in the right scope:
- default to project scope for shared repo scaffolds - use user scope for personal/global hooks or when the repo should not commit .codex/config.toml
- Inspect any existing
.codex/config.toml,.codex/hooks.json,.codex/hooks/,AGENTS.md,README*, and other automation files before choosing a merge mode. - Produce or update a concrete hook plan JSON. Keep the scaffold deterministic by putting project-specific judgment into the plan, not into the scaffold script.
- Scaffold every current official event as a commented bash stub under the managed hook root, even if that event stays disabled in
hooks.json. - Wire only the enabled events into
.codex/hooks.jsonso inactive stubs stay cheap. - Regenerate
.codex/hooks/README.mdso the target project always has a readable event map. - If hooks still appear inactive after a real scaffold, re-check the effective feature state and remember that project config files only load in trusted projects.
Feature First Heuristic
Check codex_hooks early whenever any of these signals appear:
- the user asks to scaffold Codex hooks into a repo
.codex/hooks.jsonexists, but nothing seems to happen- the user is unsure whether the feature flag is on
- a repo-local
.codex/config.tomlexists, but the effective feature still looks off
Use this flow:
- Canonicalize the target project path first.
- Run
python3 scripts/check_hooks_feature.py --project /path/to/project --json. - If the effective status is off, enable the feature deliberately:
- --scope project for shared repo-local setups - --scope user for personal/global setups
- Re-run the inspection after enabling.
- Only then spend time debugging
hooks.json, matcher choices, or hook script logic.
Live Docs First
The official Codex docs are the source of truth:
https://developers.openai.com/codex/hookshttps://developers.openai.com/codex/config-basichttps://developers.openai.com/codex/config-reference
For exact wire formats and current parser behavior, also verify:
https://github.com/openai/codex/tree/main/codex-rs/hooks/schema/generatedhttps://raw.githubusercontent.com/openai/codex/main/codex-rs/hooks/src/engine/discovery.rshttps://raw.githubusercontent.com/openai/codex/main/codex-rs/hooks/src/engine/config.rshttps://raw.githubusercontent.com/openai/codex/main/codex-rs/hooks/src/events/common.rs
Use the article at https://reading.sh/codex-hooks-just-gave-you-back-complete-control-over-your-code-57d044bcae1b as secondary material for practical patterns, not as the source of truth. Early hook writeups drifted as the feature evolved.
Project Analysis Rules
Before choosing any hook structure, inspect:
- repo root and workspace shape
- whether the project already has
.codex/config.toml,.codex/hooks.json, or.codex/hooks/ - languages and package managers
- build, test, lint, format, and validation entry points
- monorepo tools like Turborepo, Nx, pnpm workspaces, Bun workspaces, Cargo workspaces, or custom task runners
- existing AI instructions such as
AGENTS.md, project rules, or repo automation docs - existing Git hooks, Husky, Lefthook, or CI gates
- sensitive paths like
.env, secrets, lockfiles, generated code, migrations, and infra directories - whether the hook setup should be shareable in repo config or kept user-local
Run scripts/audit_project.sh first, then read references/project-analysis.md when you need the full checklist.
Deterministic vs Project-Specific Work
Keep these parts deterministic:
- managed hook root path
- event stub filenames
- generated
hooks.generated.jsonshape - merge behavior for previously managed hooks
- hooks README generation
- event manifest coverage for every current official Codex hook event
- feature-flag inspection and reporting
Allow these parts to stay project-specific:
- which events are enabled
- matcher regexes for supported events
- timeouts and status messages
- whether feature enablement belongs in project or user config
- the actual logic inside enabled event scripts
- whether the refresh is
additiveoroverhaul
Repeat-Run Rules
When the skill is invoked again against a project:
- Re-verify the live docs and schemas before assuming the event set is unchanged.
- Re-audit the project before assuming the current hook plan still fits.
- Re-check the effective feature state before assuming repo-local hooks are active.
- Preserve non-managed hooks by default.
- Treat previously generated hooks under the managed root as replaceable in
overhaulmode. - Treat previously generated hooks as append-only in
additivemode unless the managed layer or README is stale. - If the official event set or parser rules changed, update the scaffold inputs first.
Scaffold Rules
- Generate bash scripts, not Python, for the managed runtime hook stubs.
- Comment the generated bash stubs with the event-specific input and output contract.
- Default to a managed root of
.codex/hooks/generated. - Default to a hooks file target of
.codex/hooks.json. - Default to enabling
codex_hooksin.codex/config.tomlfor shared repo scaffolds. - Use
~/.codex/config.tomlonly when the hook setup should stay personal or machine-local. - Keep one managed script per official event so the event map stays obvious.
- Keep the merged
hooks.jsondeterministic: remove only previously managed handlers, never unrelated custom hooks. - Never assume
async,prompt, oragenthooks work today. The current runtime skips them. - Never pretend
PreToolUseorPostToolUsecan currently seeWrite,MCP,WebSearch, or every shell invocation. Today the useful matcher value isBash. - Treat
Stopcarefully. For that event,decision: "block"means "continue Codex with this new prompt", not "reject the turn".
Reading Guide
| Need | Read |
|---|---|
| Full audit checklist and planning questions | references/project-analysis.md |
How to inspect and enable codex_hooks safely | references/feature-flag.md |
| Current official event list, matcher support, and output semantics | references/hook-events.md |
| Managed folder layout and plan file shape | references/scaffold-layout.md |
| Additive versus overhaul behavior | references/merge-strategy.md |
| Runtime limits, docs drift, and fail-open traps | references/gotchas.md |
Operational Scripts
scripts/audit_project.shbuilds a project profile from real repo signals.scripts/check_hooks_feature.pyinspects or enablescodex_hooksin user or project config.scripts/scaffold_hooks.shrenders the managed hook tree, manifest, fragment, README, and feature setup.scripts/merge_hooks_json.shpreserves non-managed handlers while replacing previously managed ones.scripts/render_hooks_readme.shrebuilds.codex/hooks/README.mdfrom the manifest and current plan.scripts/validate.pychecks structure, frontmatter, manifest integrity, and cross-references.scripts/test_skill.pyruns lightweight validation plus temp-project integration checks.
Gotchas
PreToolUseandPostToolUseare Bash-only today. A regex likeEdit|Writeis valid, but it will not match anything useful in current Codex.matcheris ignored forUserPromptSubmitandStop. Do not design logic that depends on those matchers.async,prompt, andagentparse in config shapes, but the current runtime skips them with warnings.- Multiple matching command hooks for the same event run concurrently. One hook cannot stop another matching hook from starting.
PostToolUsecannot undo command side effects. At best it can replace the feedback Codex sees next.Stopwithdecision: "block"continues Codex with a new prompt. It does not reject the turn.- Repo-local
.codex/config.tomlonly loads in trusted projects. If you enable the feature in project scope but the project is not trusted, the effective feature can still look off. - Early blog posts described smaller event sets. Re-check the official docs and schemas every time you scaffold for real.