codex

codex is a skill for Claude Code, Codex from jdrhyne/agent-skills. It costs 55 tokens per session (1,434 once invoked), scanned B, original, MIT.

A guide for running OpenAI Codex from the command line, including tasks such as analysing, refactoring, or automatically editing code.

In plain words
What is it for?
Start a Codex task, continue a previous session, and set options such as the model, reasoning effort, working directory, and access restrictions.
Why use it?
It provides a consistent way to choose a model, reasoning level, sandbox, and command options when running Codex.

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

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for codex

README.md
[![agentmods](https://agentmods.dev/badge/skills/jdrhyne/agent-skills/codex.svg)](https://agentmods.dev/skills/jdrhyne/agent-skills/codex)
Your own site
<a href="https://agentmods.dev/skills/jdrhyne/agent-skills/codex"><img src="https://agentmods.dev/badge/skills/jdrhyne/agent-skills/codex.svg" alt="Measured on agentmods" height="20"></a>
Per session 55 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,434 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. 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 $0.00055 $0.01434
Opus 5 $0.00028 $0.00717
Sonnet 5 $0.00011 $0.00287
Haiku 4.5 $0.00006 $0.00143

Measured 5d ago against content hash d61264b1cd83, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade B, and why

codex scanned grade B with 1 finding 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 5d 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.

Reads agent configuration directoriesmediumAgent snooping

.claude/, .codex/, .gemini/ hold keys, settings and other credentials a mod has no legitimate need for.

Use `/model` slash command within a Codex session to switch models, or configure default in `~/.codex/config.toml`.
codex/codex/SKILL.md · 77 lines

How it starts

The opening of the file, as written. The whole thing — 77 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Codex Skill Guide

Running a Task

  1. Default to gpt-5.2 model. Ask the user (via AskUserQuestion) which reasoning effort to use (xhigh,high, medium, or low). User can override model if needed (see Model Options below).
  2. Select the sandbox mode required for the task; default to --sandbox read-only unless edits or network access are necessary.
  3. Assemble the command with the appropriate options:
    • -m, --model <MODEL>
    • --config model_reasoning_effort="<high|medium|low>"
    • --sandbox <read-only|workspace-write|danger-full-access>
    • --full-auto
    • -C, --cd <DIR>
    • --skip-git-repo-check
  4. Always use --skip-git-repo-check.
  5. When continuing a previous session, use codex exec --skip-git-repo-check resume --last via stdin. When resuming don't use any configuration flags unless explicitly requested by the user e.g. if he species the model or the reasoning effort when requesting to resume a session. Resume syntax: echo "your prompt here" | codex exec --skip-git-repo-check resume --last 2>/dev/null. All flags have to be inserted between exec and resume.
  6. IMPORTANT: By default, append 2>/dev/null to all codex exec commands to suppress thinking tokens (stderr). Only show stderr if the user explicitly requests to see thinking tokens or if debugging is needed.
  7. Run the command, capture stdout/stderr (filtered as appropriate), and summarize the outcome for the user.
  8. After Codex completes, inform the user: "You can resume this Codex session at any time by saying 'codex resume' or asking me to continue with additional analysis or changes."

Safety Boundaries

  • Do not run codex exec until the user has explicitly asked to use Codex for the task.
  • Do not select --full-auto or a broader sandbox mode than the task requires.
  • Do not overwrite user files, create commits, or perform destructive operations without explicit user approval.
  • Do not use networked or danger-full-access runs unless the user requested work that actually needs them.

Read the full file on GitHub · 77 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 5d ago First seen · 77 lines · 55 tokens per session scan B d61264b1cd83

Subscribe to this mod's changes

codex is a skill published in the GitHub repository jdrhyne/agent-skills (241 stars, last pushed 6d ago), licensed MIT. It adds 55 tokens to every session and 1,434 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it B with 1 finding (reads agent configuration directories). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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