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

Annotations provide no safety hints (readOnlyHint false, destructiveHint false), so the description must disclose behavior. It only says 'native wheel scrolling' without explaining side effects, permissions, prerequisites (e.g., element visibility), or consequences of scrolling. There is no mention of what happens on failure or whether it mutates UI state beyond the scroll. For a tool with no annotation support, this is a significant gap.

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 zero filler. The purpose is front-loaded, and the alternative routing follows immediately. Every word earns its place, making it easy to scan and act upon.

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 complexity (17 parameters, output schema present), the description is minimal. It clarifies the core purpose and routing but offers no guidance on selecting among the many coordinate, delta, direction, and targeting parameters. Schema coverage and output schema reduce the burden, but the description still leaves an agent without advice on typical usage patterns. Adequate but not complete for a tool this rich.

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 baseline is 3. The description adds no parameter-specific guidance beyond what the schema already provides. It does not explain when to use delta vs direction, or the role of device, which are covered in schema but not reinforced. Thus it adds no additional meaning.

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 states a specific verb and resource: 'native wheel scrolling of a desktop region or semantic UI target.' It clearly differentiates from siblings by naming browser_action scroll_into_view and ui_action scroll_into_view as the preferred alternatives for known elements. This gives an agent a precise understanding of when to invoke this 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?

Explicitly tells the agent when NOT to use this tool and names the alternatives: 'Prefer browser_action scroll_into_view for a known web element and ui_action scroll_into_view for a known accessible desktop element.' This is a clear routing rule that leaves no ambiguity about choice among siblings.

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