screenshot

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

With no annotations, the description carries the full burden and does well: it discloses the headless browser tech, base64 output, and supported formats. However, it omits details like error handling (e.g., page load failures) or behavior with dynamic content, but overall it provides sufficient transparency for a screenshot 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 extremely concise: two sentences with no wasted words. The first sentence front-loads the primary action and output format, while the second adds key variations. Every sentence 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?

Given that there is no output schema and 6 parameters, the description is fairly complete for a simple tool. It covers the main use cases (normal, full page, element). However, it does not mention error scenarios or return structure (e.g., base64 string details), which would improve completeness.

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 baseline is 3. The description adds value by grouping features (e.g., 'full page screenshots' maps to full_page, 'element screenshots via CSS selector' maps to selector). It doesn't repeat schema descriptions but provides conceptual context, earning a score above baseline.

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 action ('Take a screenshot'), the resource ('a web page'), and the method ('Chromium headless browser'). It also lists supported formats and features, making the purpose unmistakable. It distinguishes from sibling tools (like fetch_page or extract_data) by focusing on visual capture.

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 no guidance on when to use this tool versus alternatives (e.g., fetch_page for text content). It lacks explicit 'when-to-use' or 'when-not-to-use' instructions. Without this, an AI agent may incorrectly select this tool for non-visual tasks.

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