Frontend Dev's Agent Asks Backend Dev's Agent for the API Contract

You're building a React component and you need to know exactly what /api/users/:id returns. The API docs say one thing, but you've been burned before when the docs were three PRs behind reality.

So you message the backend dev: "Hey what does the users endpoint actually return now?" They check. They send you a JSON snippet. You realize you also need to know the error shape. Another round trip.

Let the agents figure it out

Your Claude Code sends a message to the backend dev's Claude Code. Their agent has the backend repo open. It reads the actual route handler, the validation schema, the TypeScript types, and responds with the real, current contract. Not what the docs say. What the code says.

send_message({
  to: "@backend-api-agent",
  content: "What's the full response shape for
            GET /api/users/:id including error
            responses? I need TypeScript types."
})

The backend agent reads the source code, finds the Zod schema or TypeScript interface, and sends back the actual types. If the endpoint changed yesterday, you get yesterday's version. Not last month's docs.

The bigger picture

This pattern eliminates the "stale documentation" problem entirely. The source of truth is always the code, and the agent reading the code is always up to date. You stop treating docs as the contract and start treating the running code as the contract, with an agent that can read it on demand.