codex-cli

A guide for asking the OpenAI Codex command-line tool to perform a task from another coding-agent environment.

In plain words
What is it for?
Use it to delegate code reviews, repository analysis, implementation work, research, or image-generation requests to Codex CLI.
Why use it?
It explains how to check whether Codex is installed, choose read-only or write access, continue sessions, and collect results.

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/sugarforever/01coder-agent-skills/codex-cli
Any agent
npx skills add sugarforever/01coder-agent-skills --skill codex-cli
Clone the repo
git clone --depth 1 https://github.com/sugarforever/01coder-agent-skills

Made for: Claude Code, Codex.

Per session 93 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,874 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 $0.00093 $0.01874
Opus 5 $0.00046 $0.00937
Sonnet 5 $0.00019 $0.00375
Haiku 4.5 $0.00009 $0.00187

Measured 3d ago against content hash dfc8f3f283ce, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

codex-cli 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 3d 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.

skills/codex-cli/SKILL.md · 236 lines

How it starts

The opening of the file, as written. The whole thing — 236 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Codex CLI

Use this skill when the user asks this agent to talk to Codex, consult Codex, delegate a coding/review/research task to Codex CLI, or ask Codex to generate an image.

The core interface is:

codex exec "prompt"

For automation, prefer non-interactive codex exec over interactive codex.

First Check

Before using Codex CLI, verify it is available:

command -v codex
codex --version
codex exec --help

If codex is missing, tell the user Codex CLI is not available in this environment and stop. Do not simulate a Codex response.

If codex exec --help is available, use it as the source of truth for the installed CLI flags. Codex CLI changes over time.

One-Off Task Workflow

Use this for normal delegation:

codex exec -C "$PWD" -s read-only "Review this repository and identify likely bugs"

For tasks that may edit files, use the sandbox the user requested or the host agent allows:

codex exec -C "$PWD" -s workspace-write "Implement the requested change"

For a response file:

codex exec -C "$PWD" -o /tmp/codex-last-message.md "Summarize this project"

For machine-readable events:

codex exec -C "$PWD" --json -o /tmp/codex-last-message.md "Analyze this project"

If the prompt is long, pass it via stdin:

codex exec -C "$PWD" - < /tmp/prompt.txt

When using shell commands from another agent, avoid dangerous flags unless the user explicitly asked for them. Prefer read-only for review, planning, critique, image generation, and analysis.

Prompt Shape

For non-trivial tasks, shape the delegated prompt with OpenAI's Codex best-practices structure:

Goal:
Context:
Constraints:
Done when:

Keep the prompt scoped to one task. For complex implementation work, ask Codex for a plan first in read-only mode, then run a separate write task after the plan is accepted.

Session Resume

Codex emits a session id in normal startup output and in JSONL events as thread.started.

Read the full file on GitHub · 236 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. 3d ago First seen · 236 lines · 93 tokens per session scan A dfc8f3f283ce

Subscribe to this mod's changes

codex-cli is a skill published in the GitHub repository sugarforever/01coder-agent-skills (133 stars, last pushed 2mo ago), licensed MIT. It adds 93 tokens to every session and 1,874 once invoked, about $0.0005 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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