variant-analysis
An agent skill by trailofbits, from trailofbits/skills. Tags: analysis, code-quality, research, security.
What it does
Hunts for the other instances of a bug already found — the variants of one root cause across a codebase. Use immediately after a vulnerability, logic bug, or bad pattern turns up in a specific file and the question becomes where else it occurs, including the bare conversational form ("are there others like this?", "is this the same bug?"). Also for generalizing one known instance into a CodeQL or Semgrep query for its whole pattern family, and for triaging a set of look-alike candidates against a known root cause. Not for initial discovery with no bug in hand.
Install
With the skills CLI, which installs into Claude Code, Codex, Cursor and other agents:
npx skills add trailofbits/skills --skill variant-analysisOr copy the skill folder into Claude Code's skills directory by hand (~/.claude/skills for every project, or .claude/skills inside one):
git clone --depth 1 https://github.com/trailofbits/skills
cp -r skills/plugins/variant-analysis/skills/variant-analysis ~/.claude/skills/variant-analysisSafety box score
Not rated yet. A safety box score grades what a skill and its scripts can reach on the machine of whoever installs it, across eight categories from shell execution to secrets access. Anyone can request one from this page; it is saved for everyone. How the score works.
Source
- Repository
- trailofbits/skills (all skills from this repository)
- Path
- plugins/variant-analysis/skills/variant-analysis/SKILL.md
- Branch
- main
- Collection
- variant-analysis
- Updated
- 2026-09-19
Related skills
- audit-context-building — Understand a codebase before looking for bugs in it - what each function assumes, what it guarantees, and what it depends on elsewhere.
- audit-prep-assistant — Prepares codebases for security review using Trail of Bits' checklist.
- c-review — Performs comprehensive C/C++ security review for memory corruption, integer overflows, race conditions, and platform-specific vulnerabilities.
- code-maturity-assessor — Systematic code maturity assessment using Trail of Bits' 9-category framework.
- constant-time-analysis — Detects timing side-channel vulnerabilities in cryptographic code.
- differential-review — Performs security-focused differential review of code changes.