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

The description adds substantial behavioral context beyond the readOnlyHint and idempotentHint annotations: it explains that MCP cannot carry the X-PAYMENT header, why the tool returns guidance rather than executing the POST, and details the result delivery and refund policy. This is rich, honest disclosure with no contradiction to the annotations.

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 concise but information-dense, covering purpose, payment, result format, refund, and next steps in a few sentences. It is front-loaded with the core action and each sentence earns its place, with no fluff.

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?

Given the tool's moderate complexity and the rich annotations/context, the description is fully complete: it explains the payment ladder, result delivery fields, grade D refund, and the required next action. It also mentions the output schema components (job_id, result, grade, result_url), so nothing essential 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?

Schema coverage for the single parameter estimate_id is 100%, with the schema already describing it as 'The estimate_id returned by extract.estimate.' The tool description references estimate_id indirectly via 'after extract.estimate' but does not add new parameter semantics beyond what the schema provides, so the baseline 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 clearly states the tool 'Returns invocation guidance for executing a paid extraction job after extract.estimate,' using a specific verb and resource. It distinguishes itself from sibling tools like extract.estimate and extract.result by focusing on guidance for the paid run rather than estimation or result retrieval.

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 specifies the tool is used 'after extract.estimate' and instructs the agent to 'execute the paid POST directly with an x402 client' after receiving the endpoint and price. This provides clear contextual usage, though it does not explicitly contrast with alternatives like extract.result, so it falls short of a 5.

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