codex-advisor

codex-advisor is a skill for Claude Code, Codex from ckorhonen/claude-skills. It costs 49 tokens per session (2,513 once invoked), scanned A, original, MIT.

A second-opinion workflow that asks the OpenAI Codex command-line tool to review plans, code, architecture choices, or difficult problems. The command-line tool runs Codex in a non-interactive mode for scripted reviews.

In plain words
What is it for?
Use it to review implementation plans, inspect complex or security-sensitive code, compare architecture options, validate assumptions in unfamiliar codebases, and investigate problems that have resisted debugging.
Why use it?
It gives you another analysis of important decisions or stuck debugging work before you commit to an approach.

Skill for Claude CodeCodex

Written for Claude Code and Codex: shipped in a Claude Code plugin, but also runs codex exec. Also seen: mentions Codex.

Part of the claude-skills plugin — 62 skills, 4 commands, 7 agents shipped together

Good fit Use it to review implementation plans, inspect complex or security-sensitive code, compare architecture options, validate assumptions in unfamiliar codebases, and investigate problems that have resisted debugging.

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

Made for: Claude Code, Codex.

Or install claude-skills, the plugin that ships this one along with the rest of its 62 skills, 4 commands, 7 agents.

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-advisor

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

Your own site · 80×15
<a href="https://agentmods.dev/skills/ckorhonen/claude-skills/codex-advisor"><img src="https://agentmods.dev/badge/skills/ckorhonen/claude-skills/codex-advisor.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 49 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,513 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00049 $0.02513
Opus 5 $0.00024 $0.01256
Sonnet 5 $0.00010 $0.00503
Haiku 4.5 $0.00005 $0.00251

Measured 9d ago against content hash 523c751acaf7, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

codex-advisor 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 9d 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-advisor/SKILL.md · 344 lines

How it starts

The opening of the file, as written. The whole thing — 344 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Codex Advisor

Overview

Use OpenAI's Codex CLI as a second-opinion advisor when you need external validation on plans, code reviews, or are stuck on hard problems. This skill uses non-interactive mode (codex exec) for scripted/automated usage.

When to Use

  • Reviewing implementation plans before starting work
  • Code review for complex or security-sensitive changes
  • Architecture decisions with significant trade-offs
  • Debugging problems where you've been stuck for >30 minutes
  • Getting alternative approaches to a solution
  • Validating assumptions about unfamiliar codebases

Prerequisites

  • OpenAI API key or ChatGPT Plus/Pro/Business account
  • Codex CLI installed

Installation

# Via npm
npm install -g @openai/codex

# Or via Homebrew
brew install --cask codex

Authentication

# Option 1: API key (required for non-interactive mode in CI)
export OPENAI_API_KEY="your-key"

# Option 2: Codex-specific key for CI environments
export CODEX_API_KEY="your-key"

# Option 3: Interactive login (one-time setup)
codex --login

Model Selection

Choose the right model for your task:

Model Best For Use When
gpt-5.2 General-purpose reasoning Default for plan reviews, architecture questions, non-coding tasks
gpt-5.2-codex Real-world software engineering Code reviews, debugging, coding-specific tasks
gpt-5.1-codex-max Extended multi-step workflows Long-running tasks (>10 min), large migrations, complex refactors
gpt-5.1-codex-mini Budget-conscious projects Simple reviews when cost matters

Recommendation:

  • Start with gpt-5.2 for general questions
  • Use gpt-5.2-codex when the task is specifically about code
  • Use gpt-5.1-codex-max for tasks involving many files or complex multi-step work

Reasoning Effort Levels

Always use xhigh reasoning for thorough analysis:

Level Use Case
xhigh Default - Deep analysis, security review, architecture decisions
high Complex analysis when latency matters
medium Quick responses for simple tasks
low/none Not recommended for advisor use cases

Read the full file on GitHub · 344 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. 9d ago First seen · 344 lines · 49 tokens per session scan A 523c751acaf7

Subscribe to this mod's changes

codex-advisor is a skill published in the GitHub repository ckorhonen/claude-skills (14 stars, last pushed 2mo ago), licensed MIT. It adds 49 tokens to every session and 2,513 once invoked, about $0.0002 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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