codex

Runs OpenAI Codex CLI for independent code review, adversarial challenge, and consult sessions.

107|7|Updated Mar 29, 2026
One-click install
npx skills add https://github.com/no-session/pstack --skill codex-no-session
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: codex
Source: https://github.com/no-session/pstack/tree/main/codex
Command: npx skills add https://github.com/no-session/pstack --skill codex-no-session

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill requires @openai/codex.

What problem does it solve? Getting a second opinion on your code from the same AI that wrote it creates blind spots. This Skill wraps the OpenAI Codex CLI so a different AI system independently reviews your diff, attacks it adversarially, or answers technical questions with session continuity. ## Core Features & Use Cases - Review Mode: Runs codex review against your branch diff with a pass/fail gate based on [P1] critical findings, plus cross-model comparison against Claude's own /review results. - Challenge Mode: Adversarial analysis that tries to break your code, hunting edge cases, race conditions, security holes, and failure modes, with optional focus areas like security. - Consult Mode: Ask Codex anything with session continuity for follow-up questions, using medium reasoning effort for interactive speed. - Use Case: Before shipping a billing change, run /codex review to get an independent pass/fail verdict, then /codex challenge security to probe for injection and auth bypass paths. ## Quick Start Ask the assistant to run /codex review on the current branch to get an independent code review with a pass/fail gate.

Frequently Asked Questions about codex

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I get a second AI opinion on my code review?▼

Run /codex review to have the OpenAI Codex CLI independently review your branch diff against the base branch. It returns a pass/fail gate based on critical [P1] findings and can compare results against Claude's own /review output.

How do I install the OpenAI Codex CLI?▼

Install it with npm install -g @openai/codex, or see the repository at github.com/openai/codex. The skill checks for the codex binary first and stops with install instructions if it is not found.

What is the difference between codex review and codex challenge?▼

Review mode produces a standard code review with a pass/fail gate on critical findings. Challenge mode is adversarial: it tries to break your code by hunting edge cases, race conditions, security holes, and failure modes, with an optional focus like security.

Does codex review work with GitLab merge requests?▼

Yes. The skill detects the platform from the git remote URL and uses glab to find the merge request target branch, falling back to git-native commands like symbolic-ref when CLI tools are unavailable.

Why does codex review fail or time out?▼

Review runs with a 5-minute timeout, so very large diffs may exceed it. Failures also occur when the codex binary is missing, the directory is not a git repository, or the base branch cannot be detected.

Can I adjust the reasoning effort Codex uses?▼

Yes. Pass --xhigh anywhere in your command to override the per-mode defaults. Review and Challenge default to high effort, while Consult defaults to medium for faster interactive responses.