browser_get_viewport_size

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does not mention that this is a read-only operation, what the return value contains (e.g., width and height), or any units. Critical information about the output is missing.

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, consisting of a single short phrase with no wasted words. It is appropriately sized for such a simple operation, though it could benefit from a bit more detail.

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 no output schema and no description of the return value, the tool is incomplete. For a getter, it is essential to know the format and meaning of the result (e.g., an object with width/height). The description also lacks context about how it applies to the current page or browser viewport.

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 tool takes zero parameters, so the baseline is 4. The description does not need to explain parameter meaning, and the schema confirms no parameters exist. Nothing is lacking in this dimension.

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 '获取视口大小' (Get viewport size) clearly states the action (get) and resource (viewport size). It is specific and easily distinguishable from the sibling browser_set_viewport_size, though it does not explicitly mention the alternative.

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?

No usage guidance is provided. The description does not state when to use this tool, when not to use it, or mention alternatives. The intended context is only implied by the verb and resource.

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