Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, non-destructive and openWorldHint, so safety and external-data traits are covered structurally. The description adds the return shape [{value,label}] and the chaining contract, but says nothing about latency, caching, empty results, or failures for providers with no connected credential — relevant given openWorldHint=true and the credentialId param. It adds value but not much behavioral depth beyond the annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.