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

No annotations are provided, so the description carries full burden. It explicitly marks the tool as 'Read-only', which is a key behavioral trait. However, it does not disclose error handling or edge cases (e.g., invalid PDF), leaving some gaps for a tool with no annotations.

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 short sentences: the first defines purpose and behavior, the second provides usage guidance. No redundant information, perfectly front-loaded.

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 info tool with one parameter and no output schema, the description adequately explains what it returns (page count and dimensions in points). Could mention whether dimensions include rotation or if it handles encrypted PDFs, but overall sufficient for an AI agent.

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% for the single parameter 'pdf', which already specifies it can be a base64 string or https URL. The description adds no further details, so 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 clearly states it returns a PDF's page count and per-page dimensions, with a specific verb ('Return') and resource ('PDF's page count and per-page dimensions'). It distinguishes from action-oriented siblings like split or rotate.

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 advises using this tool first to plan a split or rotate, providing clear context for when to use it. Could be improved by noting when not to use (e.g., if only file info needed), but sufficient for this tool.

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