codex

name

codex

description

Delegate a task or question to the OpenAI Codex CLI running as an isolated subagent, then relay its answer. Use when the user invokes /codex <prompt>, says "ask codex", "have codex look at / do X", or wants a second independent model to investigate a question or make a self-contained edit. Read-only by default; /codex --write lets Codex edit the working tree. Distinct from /codex-review, which is the structured JSON review gate — /codex is a general-purpose Codex delegate.

/codex — delegate to the Codex CLI via a subagent

Runs the OpenAI Codex CLI (codex exec) on the user's prompt inside a dispatched subagent, so Codex's (possibly large) output stays out of the main context and you relay only its answer. Codex is a genuinely independent model — good for a second opinion, an adversarial read, or offloading a self-contained investigation or edit.

Helper: codex.sh (this skill's dir) runs codex exec, captures only Codex's final message (-o), and falls back across models on failure.

When to use

• /codex <prompt> — hand any question or task to Codex against this repo.
• "ask codex to …", "have codex look at …", "get codex to write / refactor …".
• NOT the structured review gate — that's /codex-review.

How to run

1. Parse the invocation. Everything after /codex is the PROMPT. Flags:

   • --write → Codex may edit the working tree (workspace-write sandbox). Default is read-only.
   • -m <model> → pin a Codex model. --dir <path> → working root (default: repo root).

2. Dispatch ONE subagent (Agent tool, subagent_type: general-purpose). Pin the model explicitly: haiku for a plain ask/relay; sonnet if Codex is making edits and you want the result sanity-checked. Give it this task (substitute <SKILL_DIR> = this skill's base directory, and <PROMPT>):

   Run the Codex CLI and return its final answer VERBATIM — trim only banner/progress noise, do not summarize or editorialize. Run: printf %s '<PROMPT>' | bash <SKILL_DIR>/codex.sh [--write] [--stats] [-m MODEL] - (stdin form avoids quoting problems for long or quote-heavy prompts). If the script exits non-zero, report its stderr line so the caller can retry. If --write was used, also run git status --short and git --no-pager diff afterward and include a short list of what Codex changed.

   Only pass --stats when the user asked for Codex's token usage or API cost (e.g. a model comparison / cost accounting). It appends a token-usage + estimated-cost block after the answer; relay that block verbatim. Omit --stats for normal delegation so output stays clean. Cost is an estimate — override the rates with CODEX_PRICE_INPUT_PER_M / CODEX_PRICE_CACHED_PER_M / CODEX_PRICE_OUTPUT_PER_M if the model's real pricing differs.

3. Relay Codex's answer to the user, attributed ("Codex says:") so it's clear this is the second model, not you. If --write was used, review the diff the subagent returned and summarize what Codex changed before trusting it — never present Codex's edits as verified without looking at the diff.

Notes

• Read-only is the safe default; pass --write only when the user clearly wants Codex to edit files.
• Codex's output is not ground truth. Verify anything that matters — especially --write edits — against the actual code and the test suite.
• If codex.sh reports rate-limit / auth failure, tell the user and offer to retry (or try a different -m model).