What problem does it solve? Turning a settled plan or issue into code often goes wrong in two ways: the agent guesses at an underspecified design, or it declares done without running the repo's own checks. This Skill enforces a disciplined build step that resolves how to build (straight-through vs TDD), bounces thin inputs back for hardening, and proves the work with the repo's test and build gate before calling it done. ## Core Features & Use Cases - Explicit input handling: Builds from a named plan file, GitHub issue, freeform spec, or a fix round of review findings, with support for narrowing to a single phase. - Mode resolution by precedence: Picks straight-through or TDD via prompt, then agent instructions (CLAUDE.md), then repo habit, then a single ask, never imposing TDD silently. - Done-gate enforcement: Discovers the repo's own test, build, typecheck, and lint commands and requires them all to pass, with bounded fix attempts on failure. - Plan stamping and handoff: Marks built phases with a date stamp and leaves all changes unstaged for the commit step. - Use Case: You say "implement phase 2 of docs/plans/plan-sso-2026-07-23.md the TDD way" and get red-green-refactor implementation, a green test suite, a stamped plan, and unstaged changes ready to commit. ## Quick Start Ask the agent to implement a specific plan file, issue number, or spec, optionally naming a phase or a TDD preference, and let it run the repo's test and build gate before reporting done.