Designing MCP Tools for Claude Code: 4 Lessons on Schema-Driven Integration

Building effective MCP servers requires careful tool design — vague schemas cause models to call tools with garbage arguments, making them worse than useless. This hands-on walkthrough shows how precise input schemas and clear tool descriptions transform Claude Code from a general-purpose assistant into a focused, knowledge-aware agent, offering developers a pattern for extending AI tooling without retraining or prompt engineering.