A wrapper that runs the OpenAI Codex command-line tool as a separate, non-interactive coding agent. It can receive a prompt, return the agent’s reply and session ID, and resume a session.

Use it to launch Codex in the foreground or background, choose a model, pass prompts through arguments, files, or standard input, and continue previous sessions.

It lets scripts or another agent delegate a self-contained coding task without an interactive approval prompt.

codex-agent — Skill for Claude Code by TheSylvester

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.

Any agent

npx skills add TheSylvester/agentic-coding-tools --skill codex-agent

Clone the repo

git clone --depth 1 https://github.com/TheSylvester/agentic-coding-tools

Made for: Claude Code.

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/thesylvester/agentic-coding-tools/codex-agent/github.svg)](https://agentmods.dev/skills/thesylvester/agentic-coding-tools/codex-agent)

Your own site

<a href="https://agentmods.dev/skills/thesylvester/agentic-coding-tools/codex-agent"><img src="https://agentmods.dev/badge/skills/thesylvester/agentic-coding-tools/codex-agent/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/thesylvester/agentic-coding-tools/codex-agent"><img src="https://agentmods.dev/badge/skills/thesylvester/agentic-coding-tools/codex-agent.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 84 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,607 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00084	$0.01607
Opus 5.5	$0.00034	$0.00643
Sonnet 5.5	$0.00017	$0.00321
Haiku 4.5	$0.00008	$0.00161

Measured 2mo ago against content hash 5034ea22bde7, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

codex-agent 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 2mo ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/codex-agent.mjs), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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-agent/SKILL.md · 158 lines

How it starts

The opening of the file, as written. The whole thing — 158 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Codex Agent (wrapper)

This runs an autonomous agent with approvals and sandboxing disabled. The wrapper invokes codex exec --dangerously-bypass-approvals-and-sandbox, because a non-interactive run has no one to approve anything. The child agent can read, write and execute in whatever directory you launch it from. Only give it briefs you would be willing to run yourself.

Execution

Works in both foreground and background:

# Foreground (blocks until done - use a long timeout, runs can take minutes)
Bash(command: "node \"~/.claude/skills/codex-agent/scripts/codex-agent.mjs\" Your prompt here", timeout: 600000)

# Background (non-blocking - you are notified when it finishes)
Bash(command: "node \"~/.claude/skills/codex-agent/scripts/codex-agent.mjs\" Your prompt here", run_in_background: true)

Background is preferred when launching multiple agents in parallel. Codex routinely takes 2-3x longer than Claude on the same brief.

Thin wrapper around the codex CLI for non-interactive use:

Provide the prompt via arguments, PROMPT_FILE, or stdin (briefs are byte-exact)
Model selection via --model or CODEX_MODEL
Session resume via --resume or CODEX_SESSION
Auto-detects OAuth login (~/.codex/auth.json) or API keys
Clear diagnostics on failure

Prerequisites

Node 18 or newer (node --version)
Codex CLI v0.80.0+: npm install -g @openai/codex@latest
Authentication, one of:
1. codex login for ChatGPT OAuth (creates ~/.codex/auth.json)
2. OPENAI_API_KEY environment variable
3. CODEX_API_KEY environment variable (exec mode only)

Nothing else. The wrapper is a single Node script with no dependencies, so it does not need bash, GNU grep -P, GNU sort -V, awk or sed. It runs the same on Linux, macOS, WSL, and Windows (PowerShell, cmd, or Git Bash).

CODEX_HOME is honored if you have relocated your Codex configuration.

Usage

# Arguments
node "~/.claude/skills/codex-agent/scripts/codex-agent.mjs" Your prompt here

# File via env var (preferred for big briefs - byte-exact off stdin)
PROMPT_FILE=task.md node "~/.claude/skills/codex-agent/scripts/codex-agent.mjs"

# Stdin
cat task.md | node "~/.claude/skills/codex-agent/scripts/codex-agent.mjs"

Read the full file on GitHub · 158 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.

scripts/codex-agent.mjs 12 KB runs code

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.

2mo ago First seen · 158 lines · 84 tokens per session scan A 5034ea22bde7

Subscribe to this mod's changes

codex-agent is a skill published in the GitHub repository TheSylvester/agentic-coding-tools (5 stars, last pushed 2mo ago), licensed MIT. It adds 84 tokens to every session and 1,607 once invoked, about $0.0003 per session on Opus 5.5. 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 2026-08-31.

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