Agent-Friendly APIs
Build a feedback API, then build a Claude Code skill that generates the documentation agents need to use it.
API documentation now has another audience. Agents read it to decide which endpoint to call, what arguments to send, and how to recover from errors.
You'll build a feedback API for a fictional cooking school and serve its documentation from a live endpoint. Then you'll build a Claude Code skill that generates the documentation from the route handlers.
What you'll learn
- How to build a JSON-backed API with Next.js App Router
- What agents need from API documentation
- How to serve API docs as a markdown endpoint
- How Claude Code skills work: SKILL.md, frontmatter, progressive disclosure
- How to build and test a skill that generates structured documentation
Prerequisites
- Basic TypeScript
- Familiarity with Next.js App Router (API routes)
- A Vercel account
- Claude Code installed
Course sections
Section 1: Build the API. Scaffold a Next.js project and build a JSON-backed feedback API with query parameter filtering and a summary route.
Section 2: Agent-Friendly Documentation. Learn what agents need from docs, implement the llms.txt standard, and deploy the API to Vercel. You'll also inspect production skills on skills.sh.
Section 3: Build the Skill. Build and run a Claude Code skill that generates the docs. Evaluate its output against a quality checklist and refine the instructions until the endpoint works.
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