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 richly: it discloses the return shape (page-by-page text with markers, page count, file size), size/page limits (15 MB, 200 pages), failure/refusal behavior (non-PDF, unopenable, or scanned image without text layer refused before charge), and the paid x402 call model with pricing.

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?

Front-loads the purpose and output, then follows with constraints, failure behavior, sibling routing, and payment terms. Every sentence contributes operational information; there is no filler or repetition.

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?

With no annotations and no output schema, the description still gives the agent everything needed: what it returns, operational limits, refusal conditions, cost, and how to pay within the call. Nothing material is missing for correct invocation.

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%, so the baseline is 3; the description adds useful meaning by tying the `payment` parameter to a concrete price ($0.003 per call) and the x402 purchase flow, and by clarifying what kind of `url` values are accepted. It stops short of adding syntax or format detail beyond the schema, so it lands just above baseline.

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?

States a specific verb and resource ('The text of a public PDF, page by page') and describes the exact output ('every page's text with page markers, the page count and the file size'). It distinguishes itself from siblings by naming page_extract and page_markdown for non-PDF web pages.

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?

Explicitly tells the agent when to use this tool (http(s) URL of a PDF such as a whitepaper, filing, invoice or paper) and when not to ('For a web page use page_extract or page_markdown'). Also states acceptance limits and that invalid files are refused before any charge.

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