Codex Delegate

Codex Delegate

When to Use

• You want to delegate a bounded coding task to a separate codex implementer (OpenAI Codex) and then review its diff yourself.
• The user explicitly asked for delegation to this implementer.

You are the orchestrator. This skill lets you hand a bounded coding task to a separate implementer — the OpenAI Codex CLI — then review what it produced and land it yourself. You write the brief and own the judgment; Codex does the typing in its own sandbox; you verify and commit.

Nothing here is specific to one orchestrating agent. The loop needs only the ability to run a shell command and read a file, so it works the same whether you are Claude Code, OpenCode with a selected model, or any comparable agent. (It is designed for and run on Claude Code; treat other orchestrators as designed-for, not yet proven.)

When NOT to use this

• The task is small enough to just do inline — delegation overhead is not worth it.
• The codex CLI is not installed or not authenticated (run codex login).
• You want to write the code yourself, or you only need a review (use Codex's own review command).

Prerequisites (check once)

1. codex --version succeeds. If not, install (npm i -g @openai/codex) and codex login.
2. Confirm which codex is on PATH. Multiple installs are common (e.g. a current npm/nvm copy and a stale Homebrew one). command -v codex shows the active one and codex --version its version — an old binary predates flags this skill relies on (codex exec --json, -o, exec resume). The relay also records the version it ran into result.json, so a stale binary is visible after the fact.
3. You are in (or will point --cd at) the target git repository.

The loop

Run these five steps per task. Steps 1, 4, and 5 are your judgment; 2 and 3 are mechanical.

1. Write the brief

Codex sees only the text you send — no repo memory, no chat history, no shared context. Everything the task needs goes in the brief: the goal, the current state, what to change, what to leave untouched, the project's actual gate commands (discover them from the repo's CLAUDE.md/AGENTS.md/Makefile — do not assume), and a report contract. Tell Codex it will not commit (you will). Keep one task per brief. Full guidance and a template: references/writing-the-brief.md.

2. Dispatch

Send the brief to Codex with the bundled helper. It wraps codex exec, captures the run, and writes a structured result.json — so your only job is "run a command, read a file." (<skill-dir> below is this skill's installed directory — the folder containing this SKILL.md, i.e. the directory you loaded the skill from. Claude Code prints it as "Base directory for this skill" when the skill loads; on other orchestrators use that same directory — if unsure where it landed, run find ~ -name relay.mjs -path '*codex-delegate*' and substitute the directory above it.)

node "<skill-dir>/scripts/relay.mjs" --brief brief.txt --cd /path/to/repo
# read-only (review/diagnosis, no edits):   add --read-only
# continue the exact Codex session:         add --session <threadId>  (from result.json; send only the delta brief)
# fallback when no thread id is available:  add --resume-last
# hard time limit (watchdog):               add --timeout 2h  (default: off; implementation runs routinely need 1-2h)
# see all options:                          node .../relay.mjs --help

The helper defaults to a write-capable (workspace-write) sandbox and writes its artifacts to a temp dir, so the repo under review stays clean. It never commits — see step 5. Mechanics, flags, and the result.json shape: references/dispatch-and-poll.md.

3. Wait for completion

The helper blocks until Codex finishes, so back it with whatever your orchestrator offers and resume when it returns:

• Claude Code: run the Bash call with run_in_background: true; you are notified on completion.
• Plain shell / other agents: run it in the foreground for short tasks, or background it and poll the result file — … & in bash/zsh (including Git Bash/WSL), or your shell's equivalent (Start-Job in PowerShell, start /b in cmd). The run is done when result.json exists with a status. (A pre-run usage error — bad args or an empty brief — instead exits with code 2 and a stderr message and writes no result file, so check the exit code too. A missing codex binary exits 127 but does write a result.json with status codex_unavailable.)

Do not trust progress trackers over reality: a run is finished when result.json is written and the process has exited. Read the working tree, not a status line. The implementer's full report is the finalMessage field in result.json (also printed in full on stdout between the report markers).

4. Review — do not trust the self-report

Codex's result.json includes its own summary and gate claims. Re-verify, don't accept:

• Re-run the project's gates yourself (the test/lint/build commands from step 1). Never take "gates passed" on faith.
• Read the diff against the brief: did Codex do what was asked, nothing more (scope creep) and nothing less? touchedFiles in the result is your starting point.
• Run the relevant guard skills on the diff if you have them installed (clean-code-guard, test-guard, etc. from guard-skills) — this skill produces the work; those skills judge it.
• For schema/migration changes, round-trip them; for removals, grep for dangling references.

Full checklist: references/review-and-land.md.