design-an-interface

# Design an Interface $ARGUMENTS Generate 3+ radically different interface designs using parallel sub-agents, then compare. Based on "Design It Twice" from "A Philosophy of Software Design." ## Usage ``` /design-an-interface [module or interface to design] ``` ## What This Command Does 1. **Gathers** requirements and constraints 2. **Spawns** 3+ parallel sub-agents with different design constraints 3. **Presents** each design with signatures, usage examples, and trade-offs 4. **Compares** on simplicity, depth, efficiency, and correctness 5. **Synthesizes** best elements into final recommendation ## Process ### 1. Gather Requirements Before designing, understand: - [ ] What problem does this module solve? - [ ] Who are the callers? (other modules, external users, tests) - [ ] What are the key operations? - [ ] Any constraints? (performance, compatibility, existing patterns) - [ ] What should be hidden inside vs exposed? ### 2. Generate Designs (Parallel Sub-Agents) Spawn 3+ sub-agents simultaneously using Agent tool. Each gets a **radically different** constraint: | Agent | Constraint | |-------|-----------| | Agent 1 | Minimize method count — aim for 1-3 methods max | | Agent 2 | Maximize flexibility — support many use cases | | Agent 3 | Optimize for the most common case | | Agent 4 | Take inspiration from a specific paradigm/library | Each agent outputs: 1. Interface signature (types/methods) 2. Usage example (how caller uses it) 3. What this design hides inte...