Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It mentions using Faker and locale-appropriate formats, hinting at the underlying library and locale handling, but does not disclose output format, side effects, or any constraints beyond what the schema shows.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.