Capture the active mouse surface

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

Annotations already cover safety and idempotency, and the description adds useful behavior: it identifies the capture surfaces and says the text output includes image/viewport dimensions and coordinate space. It does not explain how the active surface is selected or any other limitations.

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 efficient sentences with the core capture surfaces front-loaded and no wasted wording. Every sentence contributes directly to understanding or usage.

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 simple zero-parameter screenshot tool with rich annotations, the description covers the main surfaces and the coordinate metadata needed for downstream mouse actions. A minor gap remains around how the active surface is determined or exactly what visual payload is returned.

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 has zero parameters, so schema semantics are minimal by definition. The baseline for a no-parameter tool is 4, and nothing in the description is needed to clarify parameter behavior.

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 uses a specific verb, "Capture," and names the resources: active local browser tab, cloud browser, or full Windows desktop. It is clear but does not explicitly distinguish itself from siblings such as computer_observe or browser_open.

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?

It provides clear usage context: use the returned metadata to map a visual target into mouse tool coordinates. It does not state when not to use this tool or name alternatives, so it falls short of full when/when-not guidance.

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