Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Goes well beyond the annotations: discloses exactly what gets mutated (only missing/changed machine translations), what is preserved, that it reports a count, and that it returns 503 when no translator is configured. This is rich behavioral context an agent needs before invoking a write operation.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.