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

The description clearly states what the tool returns, which is helpful. However, annotations mark readOnlyHint as false, implying possible side effects, but the description does not disclose any state changes, storage, or session behavior. It avoids contradicting the annotations but leaves the side-effect profile ambiguous.

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 sentence states the action, the resource, the output, and the purpose. The trailing [category: sign] is compact metadata. There is 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 one parameter, no output schema, and a simple purpose, the description covers the essential return values and context. It does not specify the exact output format or failure behavior, but for this low-complexity tool the description is largely sufficient for an agent to select and invoke it.

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 only parameter, file, which is already documented as 'Input file (PDF).' The description adds nothing about the parameter beyond what the schema provides, so the baseline score of 3 is appropriate.

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 and resource: 'Return page count and per-page point dimensions for a PDF.' It also explains the purpose—positioning signature fields—which clearly distinguishes this from generic PDF tools like pdf_page_count or pdf_file_info and from the sibling esign_place.

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 phrase 'so signature fields can be positioned by the editor' gives clear context for when this tool should be used: in an e-sign workflow before placing signatures. It does not explicitly mention when not to use it or name alternative siblings, but the intended context is apparent.

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