Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations declare readOnlyHint=false, destructiveHint=false, openWorldHint=false, covering the safety profile. The description adds one genuinely useful trait not in the annotations — 'May auto-load the model' — which explains the non-read-only hint and warns of a side effect. It still omits return format, batch/size limits, and any cost or latency notes.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.