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

Describes payment requirement, HTTP 402 on non-payment, and JSON response after payment. However, it does not describe the actual data content or any side effects. No contradiction with annotations as none are provided.

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?

The description is relatively short but includes cryptic phrasing like 'USCG D1 / Northeast LNM Unpaid' and 'Not a new SKU', which may confuse rather than clarify. It is a single block of text without clear structure.

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?

Lacks information about the returned JSON structure, data fields, or purpose. An agent would not know how to interpret the response. Payment mechanics are explained, but the core functionality is missing.

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 only parameter x_payment is well-described in the schema as an X-PAYMENT header value. The description does not add further details, but schema coverage is 100%, so the baseline score of 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?

The description mentions USCG D1 / Northeast LNM Unpaid but does not clearly state what data the endpoint returns. The verb 'GET' is used, but the resource's purpose remains vague and ambiguous.

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 guidance is provided on when to use this tool versus sibling tools like mariners or mariners-d11. The note 'Not a new SKU' is ambiguous and does not clarify selection criteria.

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