capture_screenshot_url

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It mentions the output format (base64 JPEG) and general use cases but lacks details on potential behavioral traits like rate limits, authentication needs, error conditions, or performance implications (e.g., timeouts for slow-loading pages). The description is functional but insufficient for a mutation-like tool (capturing external resources) without annotation support.

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 and well-structured with two sentences: the first states the core functionality and output format, and the second provides usage guidelines. Every sentence adds value without redundancy, making it easy to parse and front-loaded with essential information.

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 complexity of a screenshot tool (involving external web interactions) and the absence of both annotations and an output schema, the description is moderately complete. It covers purpose and usage but lacks details on behavioral aspects like error handling or output specifics (e.g., what the base64 string or URL looks like). This leaves gaps that could hinder effective tool invocation by an AI agent.

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%, so the schema fully documents all three parameters (url, firstScreenOnly, return_url) with clear descriptions. The description adds no additional parameter semantics beyond what's in the schema, but this is acceptable given the high coverage, resulting in a baseline score of 3.

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's purpose with specific verbs ('capture high-quality screenshots') and resources ('web pages'), specifying the output format ('base64 encoded JPEG format'). It distinguishes itself from sibling tools like 'read_url' or 'search_web' by focusing on visual capture rather than text extraction or searching.

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 provides clear usage contexts ('visually inspect a website', 'take a snapshot for analysis', 'show users what a webpage looks like'), giving practical scenarios for when to use this tool. However, it doesn't explicitly mention when NOT to use it or name specific alternatives among siblings, such as 'read_url' for text content instead of screenshots.

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