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test-mutate

Mutate source code and evaluate test detection of introduced changes.

18|4|Updated Jan 29, 2026
Search Tags:#automation#testing#qa#code-quality#mutation-testing
One-click install
npx skills add https://github.com/chrisallenlane/claude-swe-workflows --skill test-mutate
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: test-mutate
Source: https://github.com/chrisallenlane/claude-swe-workflows/tree/main/skills/test-mutate
Command: npx skills add https://github.com/chrisallenlane/claude-swe-workflows --skill test-mutate

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Mutation testing workflows identify whether your tests actually detect introduced bugs by systematically mutating source code and measuring the ability of the test suite to catch those mutations. This approach reveals gaps in test coverage that traditional line coverage metrics can miss, enabling targeted improvements to tests and higher software reliability.

Core Features & Use Cases

  • Multi-session progress tracking via the .test-mutations.json file to persist state across runs.
  • Automatic discovery of test commands and source modules to mutate, reducing setup effort.
  • Spawns specialized agents (qa-test-mutator and SWE SME) to mutate code, evaluate tests, and generate targeted tests for surviving mutations.
  • Clear reporting and guidance for selecting survivors to address, with an optional commit workflow.

Quick Start

Run /test-mutate in your project to start a mutation-testing session and follow the prompts to mutate modules.

Frequently Asked Questions about test-mutate

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
What is mutation testing and how does it reveal test coverage gaps?▼

Mutation testing systematically mutates source code and measures whether your test suite detects the introduced changes, exposing test gaps that traditional line coverage metrics miss.

How do I run mutation testing on a multi-module codebase?▼

Run /test-mutate in your project to initialize a session, select source modules to mutate, and let the engine discover test commands automatically to evaluate test detection rates.

Can I use mutation testing across different programming languages?▼

Yes, mutation testing applies to multi-module codebases across languages by using a deterministic mutation engine and discovering test commands to evaluate test suite effectiveness.

Does mutation testing work if my project lacks a deterministic test command?▼

Mutation testing requires a deterministic test command and a deterministic mutation engine to reliably evaluate whether tests detect introduced source code mutations.

How do I track mutation testing progress across multiple sessions?▼

Mutation testing tracks multi-session progress via a .test-mutations.json file that persists state, records mutation results, and provides actionable insights across runs.

What is the best way to fix test gaps found by mutation testing?▼

Mutation testing spawns specialized agents to generate targeted tests for surviving mutations, guiding you through selecting survivors to address with an optional commit workflow.

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