Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, so safety is covered. The description adds that the output is aggregated counts scoped to the coach, which is useful, but it omits whether the counts are time-windowed, whether 'legacy lost' is consolidated, or how zero-count stages appear.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single front-loaded sentence with no filler; the parenthetical stage list is long but carries real information about the returned buckets. It could trim 'for the coach' redundancy but is otherwise tight.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description correctly compensates by enumerating the stage buckets the counts are keyed by, which is the key thing an agent needs. It stops short of describing ordering, totals, or time scope, leaving a small gap.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool takes zero parameters, so there is nothing for the description to disambiguate; baseline 4 applies. The enumerated stage names actually describe the shape of the result categories rather than any input.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb+resource (counts of prospects) and enumerates the pipeline stages that structure the result, which is more informative than the bare name. It does not explicitly differentiate itself from sibling list_prospects or update_prospect_status, but the aggregation framing makes the distinction reasonably inferable.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no explicit when-to-use guidance and no named alternative (e.g., 'use list_prospects when you need the underlying records rather than counts'). The phrase 'for the coach' hints at the calling context but does not tell the agent when this is the right tool versus list_prospects.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.