Tools & MCP

A practical field guide to designing tools and protocol surfaces that agents can use safely.

The map

This book moves from tool contracts through MCP architecture, lifecycle, permissions, testing, and release readiness.

01 · Tool contractsDesign clear schemas, semantics, and failure behavior.

02 · MCP architectureUnderstand hosts, clients, servers, transports, and capabilities.

03 · LifecycleInitialize, negotiate, invoke, cancel, and recover correctly.

04 · SafetyBound authority and make consequential actions visible.

05 · TestingVerify contracts and trace behavior across boundaries.

06 · ChecklistShip interoperable tools with operational evidence.

A living book

Expand these writing frames with implementations, protocol notes, and tool-design lessons.