contractslisted

# Contracts Skill Contracts define interfaces between parallel tasks. They enable safe concurrent implementation by making dependencies explicit. ## When to Load This Skill - Architect: When defining contracts in design - Executor: When materializing contracts before implementation - Implementer: When implementing or consuming contracts - Contract-Resolver: When modifying contracts ## Contract Lifecycle ``` DESIGN → MATERIALIZE → IMPLEMENT → VERIFY → (RESOLVE if blocked) ↓ ↓ ↓ ↓ ↓ Architect Executor Implementer Verifier Contract-Resolver ``` ## Phase 1: Design (Architect) Architect defines contracts in design output (compact JSON): ```json {"contracts":[{"name":"user-repository","description":"Interface for user data access","definition":"interface UserRepository { getById(id: string): Promise<User | null>; save(user: User): Promise<void>; }","used_by":["task-001","task-002","task-003"]}]} ``` **Rules for Architects:** - Define contracts for ANY cross-task dependency - Make contracts minimal but complete - Specify who provides vs consumes - Include in `execution_plan.contracts_first` ## Phase 2: Materialize (Executor) Before spawning implementers, executor writes contracts to files: ``` FOR each contract in final_design.contracts: Write to memory/contracts/{name}.json (compact JSON) ``` **Location:** `memory/contracts/{contract-name}.json` Contract file structure: ```json {"name":"user-repository","version":1,"st