Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries full burden. It discloses that the tool lists all mappers for a specific identity provider (a scoping constraint), but does not mention permission requirements, response format, or side effects. 'List' implies read-only, but no explicit statement.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.