Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden. It discloses a genuinely useful trait — that every tool call is recorded, making this an authoritative trail — and the verb 'return' implies a read-only operation. However, it omits ordering guarantees beyond 'last', whether n is capped, what an entry contains, and whether results are truncated, which matters for a log-inspection tool with zero annotation coverage.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.