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

With no annotations provided, the description carries the full burden and does so well. It discloses the payment requirement, the exact USDC amount and destination network, HTTP 402 on non-payment, the need for a valid X-PAYMENT, JSON return after payment, and chunk/watermark behavior.

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 dense and front-loaded with the endpoint and price, and every sentence carries operational information. The phrasing is a bit telegraphic and the final 'Not a new SKU' is cryptic, but the overall size is justified by the endpoint's unusual payment semantics.

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 paid endpoint with five optional parameters and no annotations, the description covers payment, authentication, errors, pagination, and pricing comprehensively enough to invoke correctly. It stops short of describing the response JSON structure, but since there is no output schema, that is a minor gap rather than a blocking one.

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%, and the schema already explains id, page, since, before, and x_payment in detail, including costs and relationships. The tool description mostly restates those semantics at a higher level, so it adds little parameter meaning beyond the schema.

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 clearly identifies the exact resource — FDA PCAC 503A briefing-memo evaluation text — served by a paid GET endpoint, which distinguishes it from sibling regulatory-document tools. It lacks a conventional subject-verb phrasing like 'Fetches...', but 'GET ... evaluation text' and the pricing make the operation plain.

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 gives explicit usage guidance within the tool: plain GET returns the newest chunk, ?id returns one official text, ?before returns an older chunk, and ?since returns texts newer than a watermark, each with its own price. It does not compare against sibling tools, but the scope is clear enough that an agent can select it.

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