# Genotoxic

Graph-informed mutation testing triage.

- Repository: https://github.com/trailofbits/skills (7935 stars)
- Category: Testing
- License: CC-BY-SA-4.0
- Last updated: 2026-10-28
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add trailofbits/skills --skill genotoxic -g -a claude-code -y`
Codex: `npx skills add trailofbits/skills --skill genotoxic -g -a codex -y`
Cursor: `npx skills add trailofbits/skills --skill genotoxic -g -a cursor -y`
Gemini CLI: `npx skills add trailofbits/skills --skill genotoxic -g -a gemini-cli -y`
Claude Code plugin marketplace: `/plugin marketplace add trailofbits/skills`

## Description

Graph-informed mutation testing triage. Parses codebases with Trailmark, runs mutation testing and necessist, then uses survived mutants, unnecessary test statements, and call graph data to identify false positives, missing test coverage, and fuzzing targets. Use when triaging survived mutants, analyzing mutation testing results, identifying test gaps, finding fuzzing targets from weak tests, running mutation frameworks (including circomvent and cairo-mutants), or using necessist.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Genotoxic

Combines mutation testing and necessist (test statement removal) with
code graph analysis to triage findings into actionable categories:
false positives, missing unit tests, and fuzzing targets.

## When to Use

- After mutation testing reveals survived mutants that need triage
- Identifying where unit tests would have the highest impact
- Finding functions that need fuzz harnesses instead of unit tests
- Prioritizing test improvements using data flow context
- Filtering out harmless mutants from actionable ones
- Finding unnecessary test statements that indicate weak assertions (necessist)

## When NOT to Use

- Codebase has no existing test suite (write tests first)
- Pure documentation or configuration changes
- Single-file scripts with trivial logic

## Prerequisites

The rest: https://github.com/trailofbits/skills/blob/HEAD/plugins/trailmark/skills/genotoxic/SKILL.md