Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context: output is deterministic, it never approves a merge (limit on its authority), and it notes repo caching for hotspot context. It does not detail receipts format, but with readOnlyHint covering the safety dimension, 4 is generous but warranted.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.