Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
readOnlyHint=true is already declared, and the description reinforces it with the 'READ-ONLY' prefix. It adds one genuine piece of behavioral context by clarifying that prompt bytes are labelled separately from observed provider tokens, which hints at data provenance. It does not state the scope (per session? per task?), whether results are cached, or freshness, so the added value is moderate.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.