Does the description explain when to use this tool, when not to, or what alternatives exist?
The phrase 'instant from the rollup' implies this is the fast, precomputed option for overall volume metrics, giving some contextual guidance. However, it never states when to use this tool versus alternatives like top_patterns, recent_events, or sql_query, nor does it mention any exclusions. The usage guidance is implied rather than explicit.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.