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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. It only lists actions and mentions PDF engines, but does not disclose behavioral traits such as side effects, auth requirements, rate limits, or what happens on failure (e.g., missing element, timeout). This is insufficient for a complex tool.

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 concise with two sentences, front-loading the purpose. However, it is under-specified for 20 parameters and could benefit from structured bullet points or grouping of related parameters.

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?

Given the tool's complexity (20 parameters, nested objects, no output schema), the description only covers actions and PDF engines. It lacks details on return values, behavior, and parameter usage, leaving the agent with insufficient context for reliable invocation.

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 only 35%, so the description must compensate. It adds value by listing actions and mentioning engines, but does not explain many parameters like clip, scale, quality, selector, etc. The agent lacks sufficient understanding of how to use these parameters correctly.

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 the tool is for visual verification only, distinguishes it from extractText, and lists the specific actions available (fullPage, viewport, element, pdf). This provides a specific verb+resource and differentiates from siblings.

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 description explicitly says 'Visual verification only. Use extractText for content,' which tells the agent when to use this tool versus alternatives. However, it does not provide further guidance on when to choose each action or when not to use the tool.

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