What problem does it solve? Executing a multi-step implementation plan requires carrying forward decisions from earlier steps; this Skill loads the full plan context and implements exactly one step correctly, test-first, without contradicting prior work. ## Core Features & Use Cases - Context-Aware Execution: Reads the plan README and all previous steps before editing, so naming, layering, and API decisions stay consistent across the plan. - Test-First Implementation: Enforces TDD (failing test, minimal code, refactor) plus gokit's engineering baseline: canonical reuse, typed APIs, acyclic layering, and no shims. - Validation and Sign-Off: Runs scoped module validation under -race -shuffle, structure checks, and review passes before marking the step done. - Use Case: Given tmp/storage-gcs-backend/02-registry.md, implement that step's actions, validate the touched Go modules, and flip its status to done so apply-plan can resume. ## Quick Start Apply step 02 of the plan in tmp/storage-gcs-backend by implementing it test-first and validating the affected modules.