PDF info

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so 'nothing is written' is largely redundant. The description does add genuine value beyond the annotations: the readable-error failure mode for non-PDFs/password-locked files and the assurance that a supplied password is used only locally.

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?

Three tight sentences with the primary action and return fields front-loaded, followed by usage routing and failure behavior. 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 output schema available, the description compensates by listing the returned fields (page count, page sizes, title, encryption) and the error behavior. It covers everything an agent needs to select and invoke the tool correctly.

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 coverage is 100%, with both parameters documented in the schema itself. The description only implies the password parameter's purpose ('needs a password') without adding format, source, or handling detail beyond what the schema states, so the baseline of 3 applies.

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 states a specific verb (read/report) and resource (PDF) and enumerates exactly what is reported: page count, page sizes, title, encryption status. This clearly separates it from mutation siblings like split_pdf and rotate_pdf.

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?

It explicitly tells the agent when to use it ('before split_pdf, extract_pdf_pages or rotate_pdf to learn the page count') and names the concrete downstream tools that depend on this information. The failure conditions (non-PDF, password-protected) further define its operating envelope.

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