Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden and does disclose the key behavioral trait: it reads local state and transmits nothing, so there are no side effects or data-egress concerns. It also states what is returned (SHA-256 plus entry count), though it omits any note on mutation safety or failure modes if the log is absent.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.