Overview
second-opinion is an open-source productivity skill for Codex and Gemini CLI, published by trailofbits. Its author describes it as: “Runs external LLM code reviews (OpenAI Codex or Google Gemini CLI) on uncommitted changes, branch diffs, or specific commits. Use when the user asks for a second opinion, external review, codex review, gemini review,…”. The project has 6.6k stars on GitHub and is available under the CC-BY-SA-4.0 license. Add it to your setup with `/plugin marketplace add trailofbits/skills`.
What second-opinion does
Shell out to external LLM CLIs for an independent code review powered by a separate model. Supports OpenAI Codex CLI and Google Gemini CLI.
What’s inside
The SKILL.md for second-opinion is organised into these sections:
- When to Use
- When NOT to Use
- Safety Note
- Quick Reference
- Invocation
- 1. Gather context interactively
- 2. Run the tool directly
- Diff Preview
- Skipping Inapplicable Checks
- Dependency Scanning
- Auto-detect Default Branch
- Codex Invocation
Installation
Add second-opinion to your agent with:
/plugin marketplace add trailofbits/skillsReview a skill’s source before installing it — skills can instruct your agent to run commands. This command comes from the skill’s public repository, which is the source of truth for setup steps. New to skills? Read how to install Claude Code skills.
Supported agents
- Claude Code — ships a claude code plugin marketplace
- Codex — named in the skill.md
- Gemini CLI — named in the skill.md
License
second-opinion is published under the CC-BY-SA-4.0 license.
Strengths
- Clear CC-BY-SA-4.0 license — safe to read and adapt within its terms
- Ships in trailofbits/skills, an established project with 6,646 GitHub stars
- Works with Claude Code, Codex, Gemini CLI
- Actively maintained — repository updated in the last 90 days
Author
Topics
Frequently asked questions
- What does second-opinion do?
- Runs external LLM code reviews (OpenAI Codex or Google Gemini CLI) on uncommitted changes, branch diffs, or specific commits. Use when the user asks for a second opinion, external review, codex review, gemini review, or mentions /second-opinion.
- How do I install second-opinion?
- Run /plugin marketplace add trailofbits/skills in your agent, then reload your skills. Review the source at https://github.com/trailofbits/skills before installing.
- Is second-opinion free to use?
- Yes. second-opinion is free and open source under the CC-BY-SA-4.0 license, so you can read, run, and adapt it within that license's terms.
- Which agents does second-opinion work with?
- second-opinion lists Claude Code, Codex, and Gemini CLI — named in its SKILL.md, its plugin marketplace or its repository topics. Skills use the portable SKILL.md format, so other agents that read that format may load it too.
- Where does second-opinion come from?
- second-opinion ships inside trailofbits/skills, a repository that contains 41 catalogued skills in total. The repository's 6,646 GitHub stars apply to that whole collection, not to this skill on its own.
