--- title: "Variant Analysis: review, setup & limitations · Undominated.ai" canonical: https://undominated.ai/skills/trailofbits-variant-analysis/ description: "Expands a confirmed vulnerability into related-code searches while preserving root-cause evidence and triage decisions." --- # Variant Analysis: review, setup & limitations · Undominated.ai > Expands a confirmed vulnerability into related-code searches while preserving root-cause evidence and triage decisions. [← Explore all skills](/skills/) SECURITY AND PRIVACY / Trail of Bits # Variant Analysis Expands a confirmed vulnerability into related-code searches while preserving root-cause evidence and triage decisions. [See setup guidance ↓](#setup)[Original source ↗](https://github.com/trailofbits/skills/blob/82fe8226252622fa807643bdca1710901198553a/plugins/variant-analysis/skills/variant-analysis/SKILL.md) SOURCE REVIEW Reviewed 2026-10-14 Evidence 3 linked sources Publisher Trail of Bits Licence [CC-BY-SA-4.0 ↗](https://github.com/trailofbits/skills/blob/82fe8226252622fa807643bdca1710901198553a/LICENSE) Revision 82fe82262526 [Read what was—and wasn’t—checked ↓](#review) “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.” [Trail of Bits · upstream description ↗](https://github.com/trailofbits/skills/blob/82fe8226252622fa807643bdca1710901198553a/plugins/variant-analysis/skills/variant-analysis/SKILL.md) Our analysis follows below. 01 / THE REASONING ## Why this made the selection. - Starts from a verified instance and broadens one abstraction at a time, with explicit false-positive review. - Bundles root-cause, search, triage and reporting references plus CodeQL and Semgrep starting templates. ### A good fit for - Searching for sibling defects after a security fix - Documenting which candidate matches are confirmed, rejected or unresolved - Expand a confirmed bug into root-cause searches across the repository, including alternate call paths ### Weigh up before choosing - Pattern matches are candidates, not confirmed vulnerabilities; reachability, sanitization and impact still need review. - The optional /variant-analysis:variants command belongs to the full upstream plugin. A skill-directory install provides the procedure and references, not that plugin command. - CodeQL and Semgrep examples are templates requiring adaptation and validation for the repository and language. - A search that does not recover the original known instance is not a validated baseline. Increasing noisy matches can make further generalization unhelpful. 02 / THE REVIEW RECORD ## What we actually inspected. Source review has boundaries. A clear record is more useful than a “safe” badge. ### Material inspected - Full SKILL.md - Root-cause, searching, triage and reporting references - Bundled query and report templates - LICENSE ### Our findings - The workflow distinguishes exact matching from broader pattern searches and requires manual candidate triage. - The definition orders exact-match baselining before broader search and treats candidate triage, failed patterns and regression detection as explicit outputs. - Steps 3 and 4 change one element at a time and stop when more than half the matches are noise. ### Not established by this review - No end-to-end agent session, effectiveness benchmark or target-project security assessment was run. - No upstream installer, helper script or generated workload was executed. The review applies to the material and revision named here. A newer upstream release can change its behavior. 03 / PUT IT TO WORK ## Add a skill to your workflow. [Upstream setup instructions ↗](https://github.com/vercel-labs/skills/blob/13e4063a1cf913f5606d57d42ab83a86f5001e04/README.md) DOCUMENTED COMMAND npx skills add trailofbits/skills/plugins/variant-analysis/skills/variant-analysis --skill variant-analysis Copy command ↗ Run in your terminal to choose your AI tools, project or global scope, and installation method. This short command follows the current upstream version; the review covers the revision shown above. Optional: install the reviewed revision Keeps the original source and installer version where recorded, while leaving your AI tools and installation scope for you to choose. npx skills add https://github.com/trailofbits/skills/tree/82fe8226252622fa807643bdca1710901198553a/plugins/variant-analysis/skills/variant-analysis --skill variant-analysis Copy reviewed-revision command ↗ - Inspect the selected skill version and its supporting files before installation. - Run the command in your terminal; choose your AI tools and project or global scope in the installer. - Keep the complete skill directory and its licence. Install any task-specific tools separately and test on a small authorized example. ### Before you start - Node.js and npm for the Skills CLI - An Agent Skills compatible coding assistant - A confirmed seed defect and access to its code context - CodeQL or Semgrep when using those optional templates ### Compatibility Agent Skills compatible clients ### Agent instructions and host-provided tools - Read the authorized codebase and confirmed defect evidence - Create search queries and reports; run separately installed search or analysis tools - Read repository-wide source and write candidate/triage reports; optional plugin orchestration starts parallel workers. ### Cost model CC BY-SA licensed instructions and helpers; agent usage and any separately chosen scanning services are additional. 04 / FOLLOW THE EVIDENCE ## The source trail. Our notes are separate from the original resource. Check upstream before adopting a new version. - [Definition at the reviewed revision ↗](https://github.com/trailofbits/skills/blob/82fe8226252622fa807643bdca1710901198553a/plugins/variant-analysis/skills/variant-analysis/SKILL.md) Checked 2026-10-14 https://github.com/trailofbits/skills/blob/82fe8226252622fa807643bdca1710901198553a/plugins/variant-analysis/skills/variant-analysis/SKILL.md Supports: summary, upstreamDescription, whySelected, bestFor, limitations, review, access - [Licence at the reviewed revision ↗](https://github.com/trailofbits/skills/blob/82fe8226252622fa807643bdca1710901198553a/LICENSE) Checked 2026-10-07 https://github.com/trailofbits/skills/blob/82fe8226252622fa807643bdca1710901198553a/LICENSE Supports: license, access.cost - [Skills CLI directory URLs and named-skill selection ↗](https://github.com/vercel-labs/skills#readme) Checked 2026-10-07 https://github.com/vercel-labs/skills#readme Supports: install, compatibility KEEP COMPARING ## Other approaches to consider. Related by category or shared topics. These are alternatives to inspect, not a measured quality order. [### Semgrep Rule Creator ↗ Turns a concrete bug pattern into a Semgrep rule with positive and negative test cases.](/skills/trailofbits-semgrep-rule-creator/)[### Supply Chain Risk Auditor ↗ Collects dependency identity, advisory and repository-maintenance evidence while retaining unassessable cases.](/skills/trailofbits-supply-chain-risk-auditor/)[### CodeQL ↗ Drives a CodeQL scan and warns that each Bash call is a fresh shell, so state must be written to files.](/skills/trailofbits-codeql/) [AI Tools ↗](/tools/)[Skills ↗](/skills/)[Agents ↗](/agents/)[MCP Servers ↗](/mcp-servers/)[Workflows ↗](/workflows/) ## Continue your investigation - [Choose a toolkit](/tools/) - [Inspect execution hosts](/agents/) - [Check tool access](/mcp-servers/) - [Check project dependencies](/check-repo/)