design-an-interface
Generate multiple radically different interface designs for a module using parallel sub-agents. Use when: user wants to design an API, explore interface options, compare module shapes, or mentions "design it twice".
What this skill does
# Design an Interface Based on "Design It Twice" from "A Philosophy of Software Design": your first idea is unlikely to be the best. Generate multiple radically different designs, then compare. ## Workflow ### 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? Ask: "What does this module need to do? Who will use it?" ### 2. Generate Designs (Parallel Sub-Agents) Spawn 3+ sub-agents simultaneously using Task tool. Each must produce a **radically different** approach. ``` Prompt template for each sub-agent: Design an interface for: [module description] Requirements: [gathered requirements] Constraints for this design: [assign a different constraint to each agent] - 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 [specific paradigm/library]" Output format: 1. Interface signature (types/methods) 2. Usage example (how caller uses it) 3. What this design hides internally 4. Trade-offs of this approach ``` ### 3. Present Designs Show each design with: 1. **Interface signature** - types, methods, params 2. **Usage examples** - how callers actually use it in practice 3. **What it hides** - complexity kept internal Present designs sequentially so user can absorb each approach before comparison. ### 4. Compare Designs After showing all designs, compare them on: - **Interface simplicity**: fewer methods, simpler params - **General-purpose vs specialized**: flexibility vs focus - **Implementation efficiency**: does shape allow efficient internals? - **Depth**: small interface hiding significant complexity (good) vs large interface with thin implementation (bad) - **Ease of correct use** vs **ease of misuse** Discuss trade-offs in prose, not tables. Highlight where designs diverge most. ### 5. Synthesize Often the best design combines insights from multiple options. Ask: - "Which design best fits your primary use case?" - "Any elements from other designs worth incorporating?" ## Evaluation Criteria From "A Philosophy of Software Design": **Interface simplicity**: Fewer methods, simpler params = easier to learn and use correctly. **General-purpose**: Can handle future use cases without changes. But beware over-generalization. **Implementation efficiency**: Does interface shape allow efficient implementation? Or force awkward internals? **Depth**: Small interface hiding significant complexity = deep module (good). Large interface with thin implementation = shallow module (avoid). ## Anti-Patterns - Don't let sub-agents produce similar designs - enforce radical difference - Don't skip comparison - the value is in contrast - Don't implement - this is purely about interface shape - Don't evaluate based on implementation effort
Related in Design
contribute
IncludedLocal-only OSS contribution command center. Auto-refreshes the user's in-flight PR and issue state on invoke so conversations start with full context — no need to brief Claude on what's in flight. Helps the user find issues to contribute to on GitHub, builds per-repo dossiers of what each upstream expects (CLA, DCO, branch convention, AI policy, draft-first, review bots, issue templates), runs deterministic gates before any external action so AI-assisted contributions don't reach maintainers as slop. State is markdown-only: candidate files at ~/.contribute-system/candidates/, repo dossiers at ~/.contribute-system/research/, append-only event log at ~/.contribute-system/log.jsonl. No database, no cloud calls. Use when the user asks about their PRs / issues / contributions, wants to find new work to take on, claim an issue, build/refresh a repo's dossier, or draft a Design Issue or PR. Trigger with "/contribute", "what's my PR status", "find a contribution", "claim issue X", "draft a Design Issue for Y", "refresh dossier for Z".
architectural-analysis
IncludedUser-triggered deep architectural analysis of a codebase or scoped subtree across eight modes — information architecture, data flow, integration points, UI surfaces, interaction patterns, data model, control flow, and failure modes. This skill should be used when the user asks to "diagram this codebase," "map the architecture," "show the data flow," "give me an ERD," "trace control flow," "find the integration points," "verify the layout pattern," "audit the UX architecture," or any similar request whose primary deliverable is mermaid diagrams plus cited reports under docs/architecture/. Dispatches haiku/sonnet sub-agents in parallel for per-mode exploration, then verifies every citation mechanically before any node lands in a diagram. Not for one-off prose explanations of code (use code-explanation) or for high-level system design from scratch (use system-design).
mcp
IncludedModel Context Protocol (MCP) server development and tool management. Languages: Python, TypeScript. Capabilities: build MCP servers, integrate external APIs, discover/execute MCP tools, manage multi-server configs, design agent-centric tools. Actions: create, build, integrate, discover, execute, configure MCP servers/tools. Keywords: MCP, Model Context Protocol, MCP server, MCP tool, stdio transport, SSE transport, tool discovery, resource provider, prompt template, external API integration, Gemini CLI MCP, Claude MCP, agent tools, tool execution, server config. Use when: building MCP servers, integrating external APIs as MCP tools, discovering available MCP tools, executing MCP capabilities, configuring multi-server setups, designing tools for AI agents.
react-native-skia
IncludedDesign, build, debug, and optimise high-polish animated graphics in React Native or Expo using @shopify/react-native-skia, Reanimated, and Gesture Handler. Use when the user wants canvas-driven UI, shaders, paths, rich text, image filters, sprite fields, Skottie, video frames, snapshots, web CanvasKit setup, or performance tuning for custom motion-heavy elements such as loaders, hero art, cards, charts, progress indicators, particle systems, or gesture-driven surfaces. Also use when the user asks for fluid, glow, glass, blob, parallax, 60fps/120fps, or GPU-friendly animated effects in React Native, even if they do not explicitly say "Skia". Do not use for ordinary form/layout work with standard views.
plaid
IncludedProduct Led AI Development — guides founders from idea to launched product. Six capabilities: Idea (discover a product idea), Validate (pressure-test the idea against fatal flaws, problem reality, competition, and 2-week MVP feasibility), Plan (vision intake + document generation), Design (translate image references into a design.md spec), Launch (go-to-market strategy), and Build (roadmap execution). Use when someone says "PLAID", "plaid idea", "help me find an idea", "product idea", "idea from my business", "idea from my expertise", "plaid validate", "validate my idea", "pressure-test", "is this idea good", "find fatal flaws", "validate the problem", "plan a product", "define my vision", "generate a PRD", "product strategy", "plaid design", "design from image", "translate image to design", "create design.md", "extract design tokens", "plaid launch", "go-to-market", "launch plan", "GTM strategy", "launch playbook", "plaid build", "build the app", "start building", or "execute the roadmap".
nextjs-framer-motion-animations
IncludedAdds production-safe Motion for React or Framer Motion animations to Next.js apps, including reveal, hover and tap micro-interactions, whileInView, stagger, AnimatePresence, layout and layoutId transitions, reorder, scroll-linked UI, and lightweight route-content transitions. Use when the user asks to add, refactor, or debug Motion or Framer Motion in App Router or Pages Router codebases, especially around server/client boundaries, reduced motion, LazyMotion, bundle size, hydration, or route transitions. Avoid for GSAP-style timelines, WebGL or 3D scenes, heavy scroll storytelling, or CSS-only effects unless Motion is explicitly requested.