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

With no annotations, the description carries the full burden. It discloses the cost ($0.475 USDC), the page limit, and the rejection behavior for oversized PDFs. It does not disclose auth requirements, whether failed calls are charged, or side effects, but the disclosed cost and rejection behavior add meaningful transparency.

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 tight sentences with no fluff. Cost and page limit are front-loaded, and the rejection behavior earns its place. It is concise without being under-specified for what it chooses to cover.

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 has four parameters, a nested expected object, no annotations, and is a paid operation, the description is incomplete. It does not explain how to provide the document, what the expected fields are for, whether the fee applies to rejected inputs, or how to choose among the sibling tools.

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 0%, so the description should compensate, but it does not explain any of the four parameters. It hints at mime_type via 'PDF/image' and at document size via '50 pages', but it never clarifies document_url vs document_base64, the expected object, or how the parameters relate to the OCR process.

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 (OCR), resource (invoices), accepted formats (PDF/image), and a key constraint (up to 50 pages). It distinguishes itself from invoice_preflight_10_pages through the page limit, though it does not explicitly name sibling alternatives.

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 useful context: this is a paid OCR tool for invoices up to 50 pages, and oversized PDFs are rejected. However, it does not explicitly say when to choose this over invoice_preflight, invoice_preflight_10_pages, or invoice_preflight_quote, nor does it state exclusions beyond the page limit.

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