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

With no annotations provided, the description carries the full burden of behavioral disclosure. The verb 'extract' implies a read-only operation, but the description does not disclose the return format, handling of invalid/corrupted PDFs, or whether password-protected files are supported. It is adequate for a simple read tool but not comprehensive.

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?

One concise sentence with no filler, front-loaded with the action and outcome. Every word adds value.

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?

Although there is no output schema, the description lists exactly what will be extracted (metadata, page count, page dimensions), which covers the expected return values. It does not specify the response structure or error conditions, but given the tool's low complexity and single parameter, the description is largely complete.

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 input schema already provides 100% coverage for the single parameter 'pdf' (Base64-encoded PDF string), so the description adds no extra parameter meaning. This matches the baseline for high schema coverage.

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 extracts metadata, page count, and page dimensions from a PDF. This specific verb and resource distinguish it from sibling tools like html_to_pdf, merge_pdfs, split_pdf, and url_to_pdf, which all perform different operations.

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 context implies it should be used when you need information about a PDF, but it does not explicitly state when not to use it or name alternatives. Since none of the sibling tools serve a similar info-extraction purpose, the usage context is clear without explicit exclusions.

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