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

The annotations already mark the tool as read-only and non-destructive. The description adds valuable behavioral details: the estimate is free, expires in 15 minutes, returns a quality grade, and includes an auto-refund for grade D. It also explains the payment via x402 USDC on Base. These go well beyond the annotation hints.

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 two dense sentences that front-load the core purpose, then list return fields, the next step, and the refund policy. Every clause adds value, and there is no filler. It is appropriately structured for an AI agent to extract key info quickly.

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 covers the tool's purpose, return payload (including nested cost_breakdown), expiry, refund policy, and integration with extract.run. With an output schema present, it does not need to detail every return field. This is a complete, self-contained description for the tool's complexity.

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 schema covers 100% of the parameters with descriptions (source_url with max size, source_type as an optional hint). The tool description repeats the source type list but does not add new semantics; it mainly provides workflow context. Given the high schema coverage, a baseline of 3 is appropriate.

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 provides a free probe and price quote for extraction, enumerates supported document types, and explicitly distinguishes itself from extract.run by noting the estimate_id is used with that sibling. This makes the purpose unmistakable and differentiates it from related 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 provides a clear workflow: get an estimate, then use extract.run with the estimate_id. It also mentions the free nature and refund policy, giving context on when to use. However, it does not explicitly list any 'when not to use' scenarios or mention alternative tools like extract.result, so it's clear but not exhaustive.

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