screenshot

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

With no annotations at all, the description must carry behavioral disclosure; it contributes only the 90-second timeout and a vague note that fields are available. It omits whether the screenshot is saved to path, what the response contains, and what 'active' means when multiple sessions exist.

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?

Two sentences, with the core purpose first and the timeout as a practical constraint second. Every sentence earns its place, though 'when needed' is slightly vague.

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 24-parameter tool with no output schema and no annotations, this description is thin: it lacks guidance on device/platform resolution, side effects of path/output, and return shape. The individual schema descriptions compensate partly, but the tool-level picture is incomplete.

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 description maps high-level concerns ('scope, density, size, annotations') to the parameter space, which is helpful given the large 24-parameter surface. Schema coverage is already 79%, so the description adds only this organizational gloss rather than compensating for undocumented parameters.

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 first sentence states an unambiguous action ('Capture a screenshot') and a clearly delimited resource ('the active app or web session'), which is enough for an agent to know what the tool does. It does not explicitly differentiate from closely related sibling tools like snapshot or record, so it stops short of the top score.

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?

There is no statement about when to choose screenshot over siblings such as snapshot, trace, or record, and no 'use X instead' guidance. The phrase 'when needed' only gestures at optional parameters, not tool-selection conditions.

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