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

With no annotations provided, the description carries the burden of behavioral disclosure. It does disclose the payment requirement, cost ($0.02 / 20000 atomic), and the 402 error for unpaid requests, which is useful. However, it omits other behaviors like whether the call is idempotent, any rate limits, or what a successful response contains. The key payment/error behavior is covered, but not comprehensively.

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 three short sentences with no fluff. It front-loads the key detail ('Paid get-one') and then adds context about the URL and error condition. Every sentence earns its place, making it very concise and well-structured.

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 simple get-one operation, the description provides the essential call context: the parameters (id, door, x_payment) are covered by the schema, and the description explains the payment prerequisite and error behavior. It does not describe the response format, but given no output schema and the simplicity of a get-one, this is a minor gap. The description sufficiently equips an agent to invoke it correctly.

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% and each parameter already has descriptive text in the schema. The description adds only the phrase 'Same URL ?id=' which slightly reinforces id usage, but does not add meaning beyond the schema. Since coverage is high, a baseline of 3 is appropriate and the description does not compensate further.

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 states the action ('Paid get-one') on a specific resource ('extracted-body door'), and distinguishes it from siblings by flagging it as paid and not a new SKU. It also mentions the URL and payment, making the purpose unambiguous. This differentiates it from free get-page or search tools.

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 implies usage context ('Paid', 'Same URL') but does not explicitly name alternatives or state when not to use this tool. It hints that a free version exists but does not guide the agent on selecting between them. No explicit exclusions or conditions beyond payment are given.

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