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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered, but the description adds 'without spending credits', which is real domain context not present in the structured fields and matters for a paid-credit API. It stops short of describing the returned grouping shape or any rate/latency behavior.

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?

Three short sentences with the verb-first headline front-loaded, followed by breakdown dimensions, scope, and cost behavior. No wasted clause, though the opening 'Count prospects.' largely restates the title.

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?

No output schema exists, so the description wisely names the aggregation dimensions (lifecycle, record type) as a proxy for the return shape, and it covers both scope modes plus the no-credit guarantee. The only shortfall is the absence of any explanation of the nested query wrapper for the single optional parameter.

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?

Schema description coverage is 0% for a nested query object containing list_id, so the description must carry the burden, and it partially does by clarifying that the single list_id selects list-scoped counting versus workspace-wide counting when omitted. It adds no format guidance (the schema requires a UUID) and does not explain why list_id sits inside a nested 'query' object.

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?

States a specific verb ('Count') plus the resource ('prospects') and narrows the result to two useful breakdowns, lifecycle and record type. An agent can tell this apart from dealmachine_prospect_search or dealmachine_get_prospects_by_record. It does not explicitly distinguish itself from the similarly named dealmachine_people_count and dealmachine_property_count siblings, which is the only gap.

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?

The scope is implied ('for the workspace or one list'), which tells the agent the two modes of use, but there is no explicit when-to-use guidance, no exclusion of alternatives like prospect_search or people_count, and no statement that list_id omission means workspace-wide.

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