Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations declare a non-read-only, non-idempotent mutation, and the description echoes 'create or update' but adds no operational context: whether omitted fields clear existing values (channel/on_call default to empty strings), whether unknown teams are auto-created, or whether this overwrites membership wholesale. For a non-idempotent write with zero schema documentation, that is a meaningful gap.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.