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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds nothing beyond that — no note on pagination behavior via next_token, no auth/permission requirements, no indication of what fields a subscriber carries.

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, purpose front-loaded, nothing bloated. The endpoint reference is largely redundant for an agent that never issues raw HTTP, but it costs little.

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?

A simple read-only list tool with full schema coverage and a safety annotation needs only modest prose. The absence of any pagination or result-shape note (no output schema exists) leaves a minor gap, but the definition is minimally sufficient.

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 100%, so sort, page_size, and next_token are fully documented in the schema. The description adds no parameter meaning, which is acceptable at this coverage level but earns only the baseline.

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 ('List') and resource ('marketing subscribers'), and the 'marketing' qualifier distinguishes it from the many user/role/permission list siblings. It does not explicitly name a sibling, but the resource is unambiguous.

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?

Provides no when-to-use guidance, no exclusions, and no routing to alternatives such as kinde_list_users. The only context is a raw REST endpoint, which does not help an agent choose the tool.

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