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

The annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so "retrieves data without changing records" largely repeats structured data. The one genuine addition is "without spending credits" — a cost trait annotations cannot express — but pagination behavior and result size are never mentioned.

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?

Short and front-loaded, but the second sentence restates the first ("List campaign recipients" / "List recipients enrolled in a campaign"), wasting budget that could have documented the id or pagination.

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?

There is no output schema, so the description should carry the return shape — it only mentions a delivery status field. With 0% schema coverage and two undocumented parameters including nested pagination, the definition leaves too much for an agent to infer before a correct call.

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% and the description adds nothing: the nested `path.id` is only labeled "Resource ID" and the description never says it is the campaign id. The `page`/`per_page` query parameters are completely undocumented in both schema and description, so an agent must guess the pagination contract.

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?

"List recipients enrolled in a campaign with their delivery status" gives a specific verb, resource, parent scope, and payload. It clearly differs from dealmachine_get_mail_campaigns_id (campaign itself) and dealmachine_get_mail_campaigns_id_analytics, though it never names a sibling explicitly.

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?

Usage is implied: read-only listing of recipients under one campaign. It never states when to prefer this over the campaign analytics, cost estimate, or properties estimate siblings, nor any prerequisite like campaign existence or required plan tier.

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