# Vector Forge

Mutation-driven test vector generation.

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

## Description

Mutation-driven test vector generation. Finds implementations of a cryptographic algorithm or protocol, runs mutation testing to identify escaped mutants, then generates new test vectors that deliberately exercise the uncovered code paths. Compares before/after mutation kill rates to prove vector effectiveness. Use when generating cryptographic test vectors, measuring Wycheproof coverage gaps, finding escaped mutants via mutation testing, creating cross-implementation test suites, or improving test vector coverage for crypto primitives.

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

# Vector Forge

Uses mutation testing to systematically identify gaps in test vector
coverage, then generates new test vectors that close those gaps.
Measures effectiveness by comparing mutation kill rates before and after.

## When to Use

- Generating test vectors for cryptographic algorithms or protocols
- Evaluating how well existing test vectors cover an implementation
- Finding implementation code paths that no test vector exercises
- Creating Wycheproof-style cross-implementation test vectors
- Measuring the concrete coverage value of a test vector suite

## When NOT to Use

- No implementations exist yet (need code to mutate)
- Single trivial implementation with no edge cases
- Testing application logic rather than algorithm implementations
- The algorithm has no public test vectors to compare against

## Prerequisites

- **trailmark** installed, if `uv run trailmark` fails, run:
  ```bash
  uv tool install trailmark
# Python snippets: uv run --with trailmark python -   (a tool env is not importable)
  ```
- At least one implementation of the target algorithm in a
  language with mutation testing support
- A test harness that consumes test vectors and exercises
  the implementation
- A mutation testing framework for the target language

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## Rationalizations to Reject

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