Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden, and it does disclose one important trait: 'sin mutar OpenDSS' signals a non-mutating, read-only validation. It says nothing, though, about what the preflight checks, whether a failure blocks downstream construction, or what the caller should do with the result.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.