Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden of behavioral disclosure. It says 'list git commits' which indicates a read-only operation, but it doesn't describe what is returned (e.g., commit hashes, messages, dates), any pagination, or ordering. The term 'lightweight history' gives a hint but not enough detail for an agent to predict behavior.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.