Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond the annotations, the description reveals crucial behaviors: the setter's destructive replace semantics, the return shape, the None sentinel for no goal set, and the tenant-scoped 404 for inaccessible projects. These details materially affect how an agent plans its calls.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.