Prove a change before claiming it is done - judge lint, typecheck, tests and git push by their exit codes rather than by reading output, and show that a bug fix's regression test fails without the fix. Use before saying "tests pass", "lint is clean", "pushed" or "fixed in <sha>"; before opening or updating a pull request; whenever a command is piped into grep, tail or head; and whenever a bug…
Install
npx skills add ehnruiz/claude-skills --skill regression-proofnpx skills add ehnruiz/claude-skills --skill regression-proof -a claude-code -gnpx skills add ehnruiz/claude-skills --skill regression-proof -a codex -ggemini skills install https://github.com/ehnruiz/claude-skills.git --path skills/regression-proofgh skill install ehnruiz/claude-skills regression-proofgit clone --depth 1 https://github.com/ehnruiz/claude-skills /tmp/ehnruiz__claude-skills
mkdir -p ~/.claude/skills ~/.agents/skills
cp -R /tmp/ehnruiz__claude-skills/skills/regression-proof ~/.claude/skills/regression-proof # Claude Code
cp -R /tmp/ehnruiz__claude-skills/skills/regression-proof ~/.agents/skills/regression-proof # Codex, Cursor, Gemini CLI, Copilot, OpenCode