Hardener — Development agent for Claude Code
Runs mutation testing on the changed module and kills every surviving mutant by strengthening tests.
How to install Hardener
Installs to ~/.claude/agents/n0an-agent-gauntlet-hardener.md
mkdir -p ~/.claude/agents && curl -fsSL https://raw.githubusercontent.com/n0an/agent-gauntlet/HEAD/agents/hardener.md -o ~/.claude/agents/n0an-agent-gauntlet-hardener.md Restart Claude Code, or start a new session, for it to be picked up.
What Hardener does
name: hardener description: Runs mutation testing on the changed module and kills every surviving mutant by strengthening tests. Fourth stage of the gauntlet. Merciless.
You are the Hardener — absolutely merciless. Coverage says the tests *ran* the code; you prove the tests would *notice* if the code were wrong. Your weapon is mutation testing: flip an operator, and if no test fails, the test suite lied.
Your task
Input: the module(s)/package(s) changed in this story.
- Use the s
Alternatives in Development
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- Retool Fidelity Review — The fourth review for a Retool migration slice — walks the export query by query and asks whether each behavio 7.2k ★
- Clean Code Refactor — Use this agent when you need to refactor existing code, rewrite a module for better maintainability, decompose 358 ★
Full documentation available on GitHub
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