| effort | medium |
| name | codex-first |
| description | Claude Code only. Delegate trusted, scoped implementation to `codex exec --yolo` — building from
a spec, refactors, mechanical migrations, bug fixes with a repro, tests, CI/dependency/tooling,
bulk code reading — while Claude writes the spec, picks `-e` effort, and reviews every diff.
Auto-routes when enabled; also `/codex-first <task>`. Keep design, ambiguous specs, tiny edits,
secrets/session-only tools, and all commit/push/GitHub ops in Claude. Unsandboxed: the review
gates the diff, not the machine.
|
| user-invocable | true |
| argument-hint | <task> |
Codex First
Claude Code only. Codex implements; Claude specs and reviews.
codex exec --yolo runs unsandboxed: --cd does not confine filesystem or network access. Claude's review gates the visible repo diff, not the machine — so delegate only trusted, scoped tasks and keep destructive/push ops Claude-side.
Route
Delegate (clear work orders): implementation from a spec, refactors, mechanical migrations, bug fixes with a known repro, tests/coverage, CI/dependency/tooling, bulk code exploration.
Keep in Claude: design/API/naming/UX judgment; ambiguous work where the spec is the work; tiny edits (≲20 lines); secrets or session-only tools (MCP/browser/1Password); and — never delegated — commits, pushes, releases, GitHub mutations, and the review itself.
/codex-first <task> delegates $ARGUMENTS immediately via the flow below.
Invoke
Write the spec, then spawn Codex with the bundled CLI — it appends fixed safety guardrails and runs codex exec --yolo from inside the repo. Prefer a clean tree (or throwaway git worktree) so the diff is attributable to Codex:
CF=~/.claude/skills/codex-first/scripts/codex-first
$CF -e <level> /abs/path/to/repo <<'EOF'
Goal: <what to build>. Target paths: <files/dirs>.
Proof: <exact command to run>.
EOF
Choose -e <level> by task difficulty (never none) — see the OpenAI reasoning guide:
-e | Use for |
|---|
low | simple, well-scoped mechanical edits; speed/cost priority |
medium | typical implementation from a clear spec — the default starting point |
high | hard reasoning: tricky multi-file changes, complex debugging, deep planning |
xhigh | only the hardest architecture/analysis, where the extra latency clearly earns it |
- Gate on the exit code: nonzero or empty output = failed run; read the
.err.
- Fix-up:
$CF -e <level> -r /abs/path/to/repo <<'EOF' … EOF resumes the repo's last session; cap at 2 rounds, then finish in Claude.
- One delegation at a time uses the default output path; pass
-o <file> for a parallel run in another repo.
Verify (always)
- Read
git -C "$REPO" status -sb + git -C "$REPO" diff (including untracked files); judge it like a PR — nothing outside the target paths, no commit/push.
- Re-run the proof yourself — Codex's claims are advisory. If the diff is wrong, fix forward or resume; never
git restore/reset it away.
Done = intended diff only, proof passes, nothing out of scope.
