pdf_to_images

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

With no annotations, the description carries behavioral disclosure itself: it discloses the default format, the single-page vs multi-page output behavior (image file vs ZIP), and the cost ('1 cent'). This is useful beyond the schema. It stops short of stating whether the source PDF is modified or how the file is returned, so not a perfect 5.

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 terse sentences front-load the core action and output, then add behavioral and cost details. Every clause earns its place and there is no repetition of schema fields.

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?

It covers the high-level outcome and pricing, and the no-output-schema gap is partially addressed by saying what artifact is returned (image or ZIP). However, it omits how the returned file is delivered/represented in the response and gives no guidance on the many parameters, so an agent could not complete nuanced calls correctly from this text alone.

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%, so the description needed to compensate for 8 undocumented parameters, but it only clarifies the format default. It does not explain dpi, quality, page ranges, output_path, or idempotency_key, leaving an agent to infer their meaning from parameter names alone.

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?

States a specific verb ('Render'), resource ('PDF pages'), and output ('JPEG (default) or PNG images'), clearly distinguishing it from generic siblings like render and from pdf_merge/pdf_split. The use-case example reinforces when this tool is appropriate.

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?

Provides a clear usage context ('to look at a document with a vision model') that tells an agent when the tool is applicable. It does not name alternatives or add when-not guidance, so it falls short of the explicit 5-level bar.

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