Tool Schema Design

Golden rules:

1. Single responsibility — one tool, one job. search_and_summarize → split into search + summarize.
2. Description = micro-tutorial — include "What it does, when to call, when NOT to call".
3. Enums beat strings — difficulty: "easy" | "medium" | "hard" constrains the model.
4. Description per param — don't leave blank. The model reads them.
5. Examples (outside input_schema) — for complex tools, add 1-2 example calls in the system prompt.
6. Required minimum — make anything optional that can be, reduces model overhead.
7. Predictable output format — model interprets results; consistent format mandatory.