ui_hover

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

The description discloses key behavioral traits: 'real pointer' indicates actual cursor movement (not simulated), and 'uniquely resolved' implies it will fail if the element is ambiguous. Although annotations (openWorldHint: false) suggest no outside impact, the description adds nuance about physical pointer movement. It could be more explicit about hover duration or side effects, but overall adds value beyond annotations.

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 a single sentence of 11 words, front-loading the core action. It wastes no words, but could be slightly expanded to include critical context without harming conciseness. It is appropriately sized given the tool's relative simplicity.

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 has six parameters, no output schema, and minimal annotations, the description is incomplete. It does not explain how to resolve an element, what happens on failure, return behavior, or timeout semantics. The tool's behavior for multiple matches or error states is omitted, leaving significant gaps for an agent.

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 input schema has six parameters with no descriptions (0% coverage), and the description does not mention any parameter meanings or constraints. For example, it does not explain that 'name' or 'xpath' are used to identify the element, nor the role of 'timeout_ms'. This forces the agent to rely solely on parameter names, which may be insufficient.

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 'move' and resource 'real pointer', clearly indicating the action. It distinguishes from sibling tools like ui_click or ui_focus by specifying 'hover' and 'uniquely resolved foreground UI element', making the purpose unambiguous.

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?

The description provides no guidance on when to use this tool versus alternatives. It does not mention scenarios like triggering hover effects or when not to use it (e.g., avoid if click is needed). Implicit differentiation may be inferred from sibling names, but no explicit usage advice is given.

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