Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond the openWorldHint annotation, the description reveals critical behavioral details: authorization happens in the browser, the agent cannot perform that step, the tool returns a link for the user, and polling is discouraged. It also warns that the user may take time, providing a realistic interaction pattern. This is excellent disclosure of side effects and edge cases.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.