codex-review

codex-review is a skill for Claude Code, Codex from ThibautBaissac/rails_ai_agents. It costs 81 tokens per session (1,164 once invoked), scanned B, original, MIT.

A workflow for getting an independent second opinion on a development plan, code change, specification, or previous answer. It sends the selected material to the Codex command-line tool for review.

In plain words
What is it for?
Cross-checking a plan, reviewing a diff, examining a specification, or challenging the last response from another coding assistant.
Why use it?
It helps expose mistakes or overlooked issues before you act on a plan or change. The review remains separate from the original response.

Skill for Claude CodeCodex

Written for Claude Code and Codex: allowed-tools in frontmatter, but also runs codex exec. Also seen: installed under .agents/ (shared by several agents); mentions Codex.

Good fit Cross-checking a plan, reviewing a diff, examining a specification, or challenging the last response from another coding assistant.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/thibautbaissac/rails_ai_agents/codex-review
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 ThibautBaissac/rails_ai_agents --skill codex-review
Clone the repo
git clone --depth 1 https://github.com/ThibautBaissac/rails_ai_agents

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-review

README.md
[![agentmods](https://agentmods.dev/badge/skills/thibautbaissac/rails_ai_agents/codex-review/github.svg)](https://agentmods.dev/skills/thibautbaissac/rails_ai_agents/codex-review)
Your own site
<a href="https://agentmods.dev/skills/thibautbaissac/rails_ai_agents/codex-review"><img src="https://agentmods.dev/badge/skills/thibautbaissac/rails_ai_agents/codex-review/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.

agentmods 80×15 button for codex-review

Your own site · 80×15
<a href="https://agentmods.dev/skills/thibautbaissac/rails_ai_agents/codex-review"><img src="https://agentmods.dev/badge/skills/thibautbaissac/rails_ai_agents/codex-review.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 81 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,164 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00081 $0.01164
Opus 5 $0.00041 $0.00582
Sonnet 5 $0.00016 $0.00233
Haiku 4.5 $0.00008 $0.00116

Measured 10d ago against content hash 687ee67760e0, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade B, and why

codex-review 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 10d 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 a single Bash call with 600000ms timeout. Capture stdout and exit code. Do **not** pass `-c model=...` — rely on the user's `~/.codex/config.toml` defaults.
.agents/skills/codex-review/SKILL.md · 102 lines

How it starts

The opening of the file, as written. The whole thing — 102 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/codex-review — Independent second opinion from Codex CLI

Argument: $ARGUMENTS — one of plan | diff | spec | last-response. Default last-response.

Never fall back to reviewing Claude's own output if Codex fails. If Codex can't run, say so and stop.

1. Preflight

Run in order. Stop cleanly on first failure:

command -v codex >/dev/null 2>&1 || { echo "codex CLI not found. Install: https://github.com/openai/codex"; exit 0; }
codex login status 2>&1 | grep -qi "logged in" || { echo "codex not logged in. Run: codex login"; exit 0; }

2. Resolve target

  • last-response (default): identify your previous substantive assistant turn (the last turn with user-facing prose — skip turns that are pure tool calls or tool results). Write that prose verbatim to a temp file via the Write tool: $(mktemp -t codex-review).md. Record the path as $TARGET_FILE.
  • plan: if there is an active in-conversation plan, write it to a temp file as above. Otherwise pick the newest file under ./.claude/plans/ (ls -t ./.claude/plans/*.md 2>/dev/null | head -1). If neither exists, report "no plan found" and stop.
  • spec: pick the newest spec.md under ./specs/ (fd -t f 'spec\.md$' ./specs 2>/dev/null | xargs ls -t 2>/dev/null | head -1). If none, stop.
  • diff: no file needed — Codex reads the repo directly via codex review --uncommitted.

3. Build rubric (skip for diff)

The diff target uses codex review's built-in review prompt — do not pass a custom rubric there (--uncommitted is mutually exclusive with [PROMPT] and will error).

For plan | spec | last-response, write this rubric to $(mktemp -t codex-rubric).txt:

You are an adversarial reviewer giving a second opinion. Be terse. Do not restate what is correct.

Check, in order:
1. Correctness — logic errors, off-by-one, wrong APIs, broken invariants.
2. Missing edge cases — nulls, empty inputs, concurrent writes, partial failures, auth gaps.
3. Simpler alternatives — is there a shorter, more conventional, or better-supported approach?
4. Risk — blast radius, reversibility, data loss, security implications.

Output format: 4 sections with those exact headings. Skip a section if you have nothing material. No preamble, no summary, no praise.

Read the full file on GitHub · 102 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. 10d ago First seen · 102 lines · 81 tokens per session scan B 687ee67760e0

Subscribe to this mod's changes

codex-review is a skill published in the GitHub repository ThibautBaissac/rails_ai_agents (661 stars, last pushed 3mo ago), licensed MIT. It adds 81 tokens to every session and 1,164 once invoked, about $0.0004 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.