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

The description adds valuable context by stating the return format (base64 PNG), which is essential since there is no output schema. It also clarifies element-level capture. Annotations already declare readOnlyHint and openWorldHint, so the extra behavioral details are helpful. However, it does not disclose other traits like waiting for page load.

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 sentence with no redundant words. It front-loads the action and result format, making it highly concise and easy to parse.

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 simple with two optional parameters and no output schema. The description covers the main behavior and return format, but fails to explain the 'full_page' parameter's behavior, which is a meaningful gap for a screenshot tool. Given the annotations, it is mostly adequate but not fully complete.

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%. The description partially maps 'specific element' to the 'selector' parameter but says nothing about 'full_page', leaving its purpose ambiguous. The agent must rely solely on the parameter name, which is insufficient.

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 function with a specific verb ('Take') and resource ('PNG screenshot'), and it distinguishes between current page and specific element capture. It does not explicitly name sibling tools like page_pdf, but the resource is distinct enough for basic identification.

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 implies when to use the tool (for visual capture of the page or an element) but provides no explicit guidance on choosing it over alternatives like page_pdf or get_html. It offers context about scope but lacks exclusions or alternative references.

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