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

It states that unpaid requests return HTTP 402 and that a valid X-PAYMENT yields JSON, revealing the payment gating and response format. However, it does not describe data side effects, rate limits, or other error conditions, leaving some behavioral aspects undisclosed.

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 short and avoids unnecessary verbosity, but it includes cryptic phrases like 'USCG D5' and 'Not a new SKU' that reduce clarity. It is concise but sacrifices comprehensibility.

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?

The description lacks context about the data returned, the meaning of 'USCG D5 / Mid-Atlantic LNM', and the tool's overall purpose. It also omits any output schema or examples, leaving substantial gaps for an agent to understand the tool's functionality.

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 described in the schema as an optional string forwarded to the paid GET as a header. The main description also references 'valid X-PAYMENT', making the parameter's role clear, though additional details such as expected format or validity conditions are absent.

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 provides a URL and payment details but does not clearly state what the tool does. References to 'USCG D5 / Mid-Atlantic LNM' and 'Not a new SKU' are cryptic without explanation, leaving the core function 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?

The description mentions payment and header requirements but gives no guidance on when to select this tool over sibling tools like mariners-d1 or d7. No selection criteria or use cases are provided.

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