codex

Instructions for running the Codex command-line tool to analyze, edit, build, test, or delegate software work.

In plain words
What is it for?
It helps run parallel coding tasks, generate or refactor code, compile projects, run tests, and continue background work.
Why use it?
It clarifies which operating mode and model to use for read-only analysis, local changes, or broader access.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/poteto/noodle/codex
Any agent
npx skills add poteto/noodle --skill codex
Clone the repo
git clone --depth 1 https://github.com/poteto/noodle

Made for: Claude Code, Codex.

Per session 63 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 892 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00063 $0.00892
Opus 5 $0.00032 $0.00446
Sonnet 5 $0.00013 $0.00178
Haiku 4.5 $0.00006 $0.00089

Measured 2d ago against content hash 277cd1242925, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

codex scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.agents/skills/codex/SKILL.md · 76 lines

How it starts

The opening of the file, as written. The whole thing — 76 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Codex

Profiles

  • (no profile) — read-only analysis (no compilation, no tests)
  • --profile edit — local edits, build, or test (workspace-write, full-auto)
  • --profile full — network or broad filesystem access (danger-full-access, full-auto)

Use --profile edit whenever the task involves go test, go build, or any command that writes build artifacts. The default read-only sandbox blocks all writes including compiler temp dirs.

For complex tasks, add --config model_reasoning_effort="xhigh".

Model Selection

Default to the project model in .codex/config.toml (gpt-5.4).

Use --model gpt-5.3-codex-spark for speed-first interactive work:

  • tight back-and-forth iteration
  • quick bug fixes and targeted edits
  • small-to-medium refactors or UI tweaks
  • rapid prototyping where frequent redirect/interrupt is expected

Stay on default gpt-5.4 for depth-first work:

  • long autonomous runs
  • broad multi-file changes with heavy reasoning
  • test-heavy or verification-heavy tasks
  • higher correctness/risk surfaces where deeper reasoning is worth the extra latency

If the user explicitly requests a model, follow the user's request.

Commands

Project defaults in .codex/config.toml. Always include --skip-git-repo-check and 2>/dev/null. Only override model when the user explicitly requests it, or when the task clearly fits the Spark speed-first criteria above.

Use case Command
Read-only analysis codex exec --skip-git-repo-check -o "$CODEX_OUT" "prompt" 2>/dev/null
Speed-first interactive loop (Spark) add --model gpt-5.3-codex-spark
Apply local edits add --profile edit
Network / broad access add --profile full
Resume session echo "prompt" | codex exec --skip-git-repo-check -o "$CODEX_OUT" resume --last 2>/dev/null

Create a temp file for output before running: CODEX_OUT=$(mktemp /tmp/codex-out.XXXXXX). Read the result from $CODEX_OUT after completion.

Run with Bash run_in_background: true. Monitor via TaskOutput with block: true, timeout: 600000 — do NOT use sleep commands to poll. Read the -o file for the final answer.

Read the full file on GitHub · 76 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 76 lines · 63 tokens per session scan A 277cd1242925

Subscribe to this mod's changes

codex is a skill published in the GitHub repository poteto/noodle (267 stars, last pushed 5mo ago), licensed MIT. It adds 63 tokens to every session and 892 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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