Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, so the safety profile is known. The description adds useful behavioral context by specifying that the check covers both the API and MCP server reachability, and that it is for unexpected failures. It does not describe return format, but the output schema exists to cover that.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.