Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden: the word 'list' implies a read-only operation, and the parenthetical enumerates the returned attributes (name, range, permissions, size), which is genuinely useful behavioral context. However, it says nothing about whether the binary must be pre-analyzed, what happens if it isn't, or whether the result is paginated or truncated for large binaries.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.