Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the burden, and it does disclose that results come from the active sequence and consist of in/out points, which implies a read-only getter and a two-value return. It does not state what happens when no sequence is active or what the values' format/units are, which is a meaningful gap for a tool with zero structured metadata.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.