api-and-interface-design

Define typed API contracts with consistent error semantics and boundary validation.

15|3|Updated Apr 9, 2026
One-click install
npx skills add https://github.com/LazyIsEfficient/agentic-os --skill api-and-interface-design-lazyisefficient
Or copy as Structured Prompt for Agent▼
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Skill: api-and-interface-design
Source: https://github.com/LazyIsEfficient/agentic-os/tree/main/.claude/skills/api-and-interface-design
Command: npx skills add https://github.com/LazyIsEfficient/agentic-os --skill api-and-interface-design-lazyisefficient

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes references (resource) components.

What problem does it solve?

Define stable, well-documented interfaces before implementation to reduce integration friction and miscommunication between components and teams.

Core Features & Use Cases

  • Contract-first interface definition with typed inputs and outputs.
  • Consistent error semantics and boundary validation.
  • Backward-compatible evolution through additive changes and clear naming conventions.
  • Use cases include designing REST/GraphQL endpoints, module boundaries, and frontend-backend contracts.

Quick Start

Draft an API contract for a new service by enumerating input/output schemas and an explicit error model before coding.

Frequently Asked Questions about api-and-interface-design

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I design a stable API contract before implementation?▼

Design a stable API contract by enumerating typed input and output schemas alongside an explicit error model before coding. This contract-first approach reduces integration friction and miscommunication between software components and teams.

What is the best way to handle API errors and boundary validation?▼

Handle API errors and boundary validation by enforcing consistent error semantics and validating inputs at the interface boundary. This ensures stable consumer-facing interfaces across backend and frontend integrations.

How do I evolve a REST or GraphQL API without breaking compatibility?▼

Evolve REST or GraphQL APIs without breaking compatibility by applying additive changes and clear naming conventions. This backward-compatible evolution strategy maintains stable contracts as your service grows.

When do I need contract-first interface design for module boundaries?▼

You need contract-first interface design for module boundaries when defining stable, well-documented interfaces before implementation is critical to reduce integration friction and miscommunication between components and teams.

Does this approach work for both REST and GraphQL endpoints?▼

Yes, this approach works for both REST and GraphQL endpoints, as well as module boundaries and frontend-backend contracts. It enforces typed schemas and consistent error semantics across consumer-facing interfaces.