browser_screenshot

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

With no annotations provided, the description carries the full burden. It discloses the key behavioral aspect that the image is not shown to the model, and it states what is returned (absolute path and size). This is transparent and useful, though it could have mentioned file overwrite behavior or error conditions.

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, two sentences, with the core purpose and key exclusion front-loaded. Every sentence contributes value, and the structure is clear and scannable.

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 description covers the main output (file path and size) and explicitly states it does not show the image, which is critical for an agent. While it doesn't mention prerequisites like needing a loaded page or error handling, the output schema likely covers return details, and the tool is simple enough that this is sufficient.

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 parameters are already documented. The description adds minimal extra meaning beyond the schema, such as referencing the screenshot directory. Since the schema covers the parameters, a baseline score of 3 is appropriate.

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 (current viewport), and the output format (PNG). It explicitly distinguishes from browser_snapshot by noting it does not show the image to the model, which differentiates it from the sibling tool.

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 explicitly tells the agent when to use this tool versus the alternative: 'Does NOT show the image to the model — use browser_snapshot for content.' This provides a clear routing decision and prevents misuse.

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