Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It discloses that the tool lists real skills and agents along with their titles, which implies a read-only, non-destructive operation. However, it does not mention output format, whether pagination applies, or any authentication requirements, leaving meaningful behavioral gaps for a tool with zero annotation coverage.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.