Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and openWorldHint=false, so safety and scope are covered by structured data. The description adds useful behavioral context beyond that: it tells the agent what payload to expect (company facts, commercial model, credentials, onboarding) and, via the invoicing parenthetical, signals the depth of the commercial-model content. It does not state whether the response is static or whether any authentication is implied.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.