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

With no annotations provided, the description carries full behavioral burden and does it well: it discloses the $0.05 USDC payment requirement and recipient address, the HTTP 402 on unpaid requests, and the JSON response after a valid X-PAYMENT. This gives the agent crucial side-effect and failure-mode information before invocation.

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 core information is packed into a short, front-loaded description with the endpoint and payment terms first. The phrase 'Not a new SKU' is cryptic and does not clearly earn its place, which keeps this from a 5.

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?

For a one-parameter paid fetch with no output schema, the description is fairly complete: it covers cost, address, unpaid behavior, and response type. It still leaves the exact JSON shape and any handling of the 402 payment flow implicit, but those are minor for basic invocation.

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%, so the schema already documents x_payment as an optional x402 value forwarded as the X-PAYMENT header. The prose mention of 'valid X-PAYMENT' reinforces that behavior but adds little new semantic detail beyond the structured description.

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 identifies the resource (US CSB final investigation report PDFs), the HTTP method, and the paid endpoint. It is clear enough to distinguish this tool from sibling report tools by its CSB-specific subject, though it never states a plain function verb like 'retrieves' and includes the cryptic 'Not a new SKU'.

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 explains the payment flow but gives no guidance about when to choose csb-reports over alternatives such as aaib-reports, get-one, or search. There is no when/when-not language or named alternative, so an agent has to infer selection from the name alone.

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