mobbin_screenshot

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

With no annotations, the description carries the burden of behavioral disclosure. It states the tool captures the current browser viewport and returns a PNG image, making the read-only nature and output format explicit. It does not mention any side effects, which is appropriate for a screenshot action. This is adequate for the tool's simplicity.

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 front-loaded: 'Take a screenshot of the current browser viewport.' The subsequent sentences about output and usage add necessary value without redundancy. Every sentence earns its place, and the overall length is appropriate.

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 tool's simplicity—one optional parameter, no output schema, and no annotations—the description is complete. It explains the action, the output format, and the intended use case. The sibling tool names provide additional context about the browser automation environment, making this description sufficient for an agent to select and invoke the tool correctly.

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?

The schema description coverage is 100%, with the fullPage parameter fully described in the schema. The description adds no additional parameter details beyond referencing 'current browser viewport,' which aligns with the default behavior. Since the schema already provides complete parameter semantics, 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 of the current browser viewport.' It specifies the resource (browser viewport) and output (PNG image). This distinguishes it from sibling tools like mobbin_extract or mobbin_download, which serve different purposes.

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 context for when to use the tool: 'Use this to see what is currently displayed on the Mobbin page.' It does not explicitly mention alternatives or when not to use it, but the use case is evident. It explains the practical benefit without requiring the agent to infer.

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