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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is covered. The description adds nothing beyond that — no disclosure of pagination behavior, result shape, or rate limiting — so it contributes no behavioral context of its own.

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?

Two short fragments with zero padding, and the resource scope is front-loaded ahead of the endpoint reference. It is terse to the point of under-specification, but nothing is wasted.

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 carries some burden for return behavior, and it says nothing about pagination fields (next_page) hinted at in the page parameter. With params fully documented in the schema and annotations covering safety, this is minimally adequate rather than complete.

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 coverage is 100%: from/to ISO 8601 ranges, page, and limit are all documented in the schema itself. The description adds no syntax or format detail beyond the schema, so the baseline 3 applies.

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 resource and scope: contacts that unsubscribed from the account, with the backing endpoint GET /contacts/unsubscribed. This clearly separates it from sendlane_list_contacts, but it never explicitly contrasts with the sibling sendlane_list_list_unsubscribed, so the scope distinction remains inferable rather than stated.

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?

No when-to-use guidance, no prerequisites, and no mention of the near-identical sibling sendlane_list_list_unsubscribed (unsubscribes scoped to a specific list). The agent must infer account-wide vs list-scoped semantics on its own.

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