Rudder is a local Codex/Claude Code plugin that captures your specs and your coding agent session history to force your agent to rewrite unit tests exclusively from your expressed intent. This turns unit test coverage into a proxy for what percent of the code actually comes from decisions you've made and lets you see how much of your agent's generated code is uncovered by your spec. After showing you an initial coverage percentage, Rudder prompts you with targeted questions to increase coverage to your goal target and runs a red-green test driven development flow to get you up to your goal. Hitting coverage is the equivalent of saying "My decisions in chat conversation cover X% of the code here."

It's fully open source and free to use, made for spec driven developers and vibecoders alike. Let me know what you guys think!