ui_scroll

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

With no annotations, the description carries the whole burden and does self-declare the critical trait: 'SIDE EFFECTS: STATE_MUTATING (Dispatches wheel events).' It also states the default amount, but omits focus/targeting prerequisites (which element or window must be active) and any rate or reliability notes.

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?

Front-loaded with purpose, then labeled WHEN TO USE / SIDE EFFECTS / LIMITATIONS sections that make it highly scannable. The LIMITATIONS line slightly duplicates the schema default, and 'in specified direction' is redundant, but overall it is tight.

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 2-parameter, 100%-covered tool with no output schema, the description covers purpose, invocation context, side-effect class, and a limitation. Only focus/targeting prerequisites are missing for a UI-automation action.

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 both parameters are already documented in the schema, including the enum of directions and the 300px default. The description restates 'in specified direction' and the 300px default without adding format or usage nuance, so baseline 3 applies.

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?

States a specific verb and resource: 'Dispatch mouse wheel scroll events across chart canvas or page in specified direction.' An agent can distinguish this from click/hover siblings by the scroll-specific verb, though no sibling is named explicitly to route among the many ui_* and chart_* tools.

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?

Explicit 'WHEN TO USE' clause scopes it to scrolling long lists, logs, or panning canvas, which is concrete context. It lacks any when-not or alternative-tool guidance (e.g. vs chart_scroll_to_date or ui_keyboard), so it stops short of full routing guidance.

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