pdf_info

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is fully covered elsewhere. The description adds essentially only a list of returned fields, which duplicates the output schema and does not disclose behavior on corrupt, password-protected, or missing files.

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?

A single front-loaded line with no filler; every item listed is a real output field. It is efficient, though efficiency here partly reflects under-specification rather than disciplined editing.

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 one-parameter read-only tool with an output schema that already documents return values, the description is close to sufficient. The remaining gap is the undocumented input_path parameter and the absence of any note on failure modes for invalid or encrypted PDFs.

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?

There is one parameter (input_path) with 0% schema description coverage, so the description carries the full burden of explaining it — and it never mentions the parameter at all. It does not say whether the path is absolute or relative, or what filesystem scope is expected.

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 names the resource (PDF metadata) and enumerates the concrete fields returned (page count, file size, encryption, title, author, creator), which is enough to distinguish it from pdf_extract_text, pdf_merge and the image/audio/video_info siblings. However, it is a noun-phrase fragment with no verb ("get"/"read"), so the action must be inferred.

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?

There is no guidance on when to call this versus pdf_extract_text or the other *_info tools, and no mention of preconditions such as the path needing to exist. The agent must infer everything about selection from the sibling names alone.

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