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

Annotations already cover the safety profile (readOnlyHint, openWorldHint), so the description's job is to add other traits — and it does, disclosing the $0.01 USDC per-call charge under x402 or credits, which is genuinely decision-relevant. It stops short of describing failure behavior or whether extraction is cached/async.

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?

Two tight sentences, front-loaded with the action and constraint followed by the cost. Every clause carries information; no filler.

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 read-only single-parameter tool with no output schema, the description covers action, input limit, and pricing — enough to call it correctly. It could still note the return shape (page-delimited text) but that gap is minor.

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?

With a single required parameter at 100% schema coverage, the schema fully documents 'url'. The description's 'up to 20MB' constraint adds a little practical meaning, but nothing about accepted URL schemes or edge cases beyond the schema.

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 (Extract) and resource (per-page text from a PDF URL), with the key constraint (up to 20MB) inline. Sibling tools are unrelated lookup/feed utilities, so no differentiation is required and none is needed.

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?

No guidance on when to prefer this over extract_page or any alternative, no mention of what happens with non-PDF URLs, password-protected files, or scanned PDFs. The size cap and cost are constraints rather than routing guidance.

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