Overview
fp-check is an open-source security skill for Claude Code and compatible agents, published by trailofbits. Its author describes it as: “Systematically verifies suspected security bugs to eliminate false positives, producing a TRUE POSITIVE or FALSE POSITIVE verdict with documented evidence for each. Use when asked whether a specific finding is real, e…”. 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 fp-check does
- "Is this bug real?" or "is this a true positive?" - "Is this a false positive?" or "verify this finding" - "Check if this vulnerability is exploitable" - Any request to verify or validate a specific suspected bug
What’s inside
The SKILL.md for fp-check is organised into these sections:
- When to Use
- When NOT to Use
- Rationalizations to Reject
- Step 0: Understand the Claim and Context
- Route: Standard vs Deep Verification
- Standard Verification
- Deep Verification
- Default
- Batch Triage
- Final Summary
- References
Installation
Add fp-check 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
License
fp-check 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
- Actively maintained — repository updated in the last 90 days
Author
Topics
Frequently asked questions
- What does fp-check do?
- Systematically verifies suspected security bugs to eliminate false positives, producing a TRUE POSITIVE or FALSE POSITIVE verdict with documented evidence for each. Use when asked whether a specific finding is real, exploitable, or a false positive, or to verify or validate a suspected vulnerability — not for hunting or discovering new bugs.
- How do I install fp-check?
- 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 fp-check free to use?
- Yes. fp-check 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 fp-check work with?
- fp-check lists Claude Code — 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 fp-check come from?
- fp-check 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.