screenshot

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

With no annotations, the description carries the full burden. It discloses format tradeoffs, default png, quality range, and optional full page/element capture. However, it does not state the return type (e.g., image data or file path), default viewport behavior, or what the 'selector' parameter expects. It adds useful behavioral context but leaves significant gaps.

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 sentences with no wasted words. The core action is front-loaded, and the format guidance is compactly integrated. Every clause earns its place.

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?

For a 4-parameter tool with no output schema and no annotations, the description is moderately helpful but incomplete: it omits return value details and precise semantics for fullPage and selector. An agent could likely handle a basic viewport screenshot but may struggle with element capture or interpreting the result.

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 25% (only quality has a description), so the description must compensate. It explains format and quality tradeoffs and mentions full page/element options, but it does not clarify the exact semantics of fullPage (default value, viewport vs full scroll) or selector (CSS selector vs other syntax). It adds value but does not fully cover the undocumented parameters.

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 states a specific verb and resource: 'Capture a screenshot of the current page' with optional full page or element capture. It is clear about the tool's function, but it does not explicitly distinguish itself from the sibling 'snapshot' tool, so it falls short of a 5.

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 format-selection guidance ('jpeg' for lighter/faster capture, 'png' is lossless) but gives no guidance on when to use screenshot versus the sibling snapshot tool or other browser tools. There is no when-not-to-use information or alternative recommendations, leaving tool selection to inference.

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