principle-engineer-tddlisted

# principle-engineer-tdd Drive every implementation outside-in with TDD. The acceptance test from the GitHub issue under work is the goalpost; modules are grown inward with one-behavior red/green/refactor loops; real adapters earn their own contract tests; wiring is proven by the acceptance test going green. Each red, green, and refactor step is its own commit, formatted per the dispatched caller's local `templates/commit-messages.md`. ## When to activate Activate this skill whenever the user: - Asks to implement, build, add, create, ship, develop, or code a feature, module, component, endpoint, handler, service, function, class, or behavior. - References a GitHub issue (e.g. `#<n>`, an issue URL, or `gh issue view <n>`), or asks to "satisfy the issue" / "work on the next ticket". - Says things like "let's implement X", "add support for Y", "build a feature for Z", "make this work", "ship the feature". - Is about to write production code without a failing test in front of it — pause and start at the acceptance test instead. - Is fixing a bug in production code — write the failing test that reproduces the bug first, then make it pass. Do NOT activate when: - The user is doing pure exploration, prototyping a throwaway spike, or asking conceptual/explanatory questions. - The change is non-behavioral: formatting, comments, type-only renames, dependency bumps, or doc edits. - The user has explicitly opted out of TDD for this task (rare — push back once before complying). ##