pdf_add_image

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. 'Add an image' implies mutation, but it does not explain whether the PDF is modified in place, what coordinate system is used, or what the output will be. Critical behavioral context such as file overwriting, page number validity, or error handling is absent.

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?

The description is a single short sentence, which is efficient and free of fluff. However, it is under-specified, bordering on terse, as it omits essential details. It is not as extreme as a tautology, but it sacrifices clarity for brevity, resulting in a middling score.

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?

The tool is complex with 7 required parameters, no annotations, and no schema parameter descriptions. The description 'Add an image to a PDF' is grossly inadequate to guide an agent on how to correctly invoke it. It does not cover positioning, page selection, image scaling, or any other necessary operational context.

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 0%, and the description adds no meaning to any of the 7 required parameters. It does not explain what x, y, width, height represent, how page_number is used, or what image formats are accepted. The tool has many parameters, and the description fails to compensate for the complete lack of schema descriptions.

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 'Add an image to a PDF' clearly states the action (add) and resource (image to a PDF). It distinguishes from siblings like pdf_add_text and pdf_add_annotation by specifying 'image' rather than other content types. However, it lacks any detail about placement or constraints, so it is not fully specific.

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 use this tool versus alternatives like pdf_add_text or pdf_add_annotation. The description provides no context about suitable scenarios, prerequisites, or when other tools should be preferred. It gives no usage directions.

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