mdproof

Use when: writing E2E, integration, or smoke tests; verifying CLI tools, APIs, or deployments; creating executable documentation; running existing runbook or proof files; or after implementing a feature to verify it works. Activate when the project has *_runbook.md/*_proof.md files, a mdproof.json config, or the user mentions mdproof/runbook/proof. Executable runbook runner — turns Markdown into real tests with bash execution, 6 assertion types (substring, regex, exit_code, jq, negation, snapshot), and source-aware failure reporting that points to the exact Markdown file and line.

Write and run E2E test runbooks that exercise the mdproof CLI itself. Use this skill whenever you need to: verify a new feature works end-to-end, validate a bug fix via a reproducible markdown runbook, test CLI flags (--dry-run, --fail-fast, --steps, --report json, --output), regression-test assertion types (substring, regex, exit_code, jq, snapshot), or confirm that parser/executor changes didn't break real-world runbook files. This skill produces .md files in runbooks/ that mdproof can run against itself — the tool testing itself. If you're about to write or run an E2E test for mdproof, use this skill first.

Run CLI commands, tests, and debugging inside the mdproof devcontainer. Use this skill whenever you need to: execute mdproof CLI commands, run Go tests (unit or integration), reproduce bugs, test new features, run E2E runbooks, or perform any operation that requires a Linux container environment. mdproof refuses to execute outside Docker by design — the devcontainer is the correct place to run and test it. If you are about to use Bash to run `mdproof`, `go test`, or `make test`, stop and use this skill first to ensure correct container execution.

Update all documentation (skills/, docs/, README.md, CHANGELOG.md) to match recent code changes, cross-validating every flag and config field against Go source. Use this skill whenever the user asks to: update docs, sync docs with code, document a new flag or config option, fix stale docs, or refresh documentation after implementing a feature. This skill covers: docs/ (user-facing guides: cli-reference.md, writing-runbooks.md, advanced.md), skills/SKILL.md (AI agent skill), skills/references/ (assertions, advanced features), README.md (project overview), and CHANGELOG.md. If you just implemented a feature and need to update documentation, this is the skill to use. Never manually edit docs without cross-validating against Go source first.

Implement a feature from a spec file or description using TDD workflow. Use this skill whenever the user asks to: add a new CLI flag, implement a feature, build new functionality, create a new internal package, add an assertion type, extend the parser, or write Go code for mdproof. This skill enforces test-first development and proper package structure. If the request involves writing Go code and tests, use this skill — even if the user doesn't explicitly say "implement".

Generate CHANGELOG.md entry from recent commits in conventional format. Use this skill whenever the user asks to: write release notes, generate a changelog, prepare a version release, document what changed between tags, or create a new CHANGELOG entry. Do NOT manually edit CHANGELOG.md without this skill — it ensures proper formatting and user-perspective writing.