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

Annotations already indicate safety (readOnly, idempotent). The description adds meaningful behavioral details such as 'full JavaScript execution', 'custom viewport width', 'lazy content loading', and 'wait delay'. This goes beyond annotations and helps the agent understand the tool's runtime behavior.

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 two concise sentences, front-loaded with the core purpose, and includes key features. Every word adds value, no redundancy.

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 has 4 parameters and an output schema, the description covers the main functional aspects (URL input, viewport, delays, output). It is complete enough for an agent to understand and invoke the tool, though it could mention potential limitations (e.g., page size, authentication) but these are minor gaps.

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 coverage is 100%, so parameters are already well-documented. The description adds marginal value by mentioning features like 'lazy content loading' and 'wait delay', but these are already captured in the schema descriptions. No additional semantic context beyond what the schema provides.

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 'Render any web page URL to PDF' with specific features (JavaScript execution, viewport width, lazy loading, delay). It distinguishes the tool from siblings like document.convert.from_pdf and document.pdf.from_url by specifying the conversion direction and capabilities.

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 does not explicitly state when to use this tool over alternatives (e.g., document.pdf.from_url or document.convert.from_pdf). While it implies usage for converting live web pages, it lacks explicit guidance on context or exclusions.

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