Hover

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

With no annotations, the description carries the full burden, and it does disclose a genuine behavioral trait: it drives a real mouse via CDP and degrades to synthetic events when CDP is unavailable. That is useful context beyond structured fields, but it omits timing/targeting behavior, whether the pointer state persists, and any environment/permission constraints.

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 tight sentences with no filler; the core action and its outcomes are front-loaded, followed by the fallback caveat. Every clause carries information.

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 9-parameter tool with no annotations and no output schema, the description is too thin. It does not explain the target-selection params (ref/text/selector), the trusted flag, step-based movement, or the durationMs post-hover hold, leaving significant gaps for an agent trying to invoke it correctly.

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 only 22% across 9 parameters, so the description should compensate but adds nothing about ref, text, selector, trusted, steps, or durationMs. Two parameters (duration, durationMs) are documented only in the schema, and the description never clarifies which targeting param takes precedence.

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 (move the real mouse over an element) plus the concrete outcomes it enables (CSS :hover, tooltips, menus), which separates it from siblings like click and press. It is clear and self-contained, though it never names an alternative tool it competes with.

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 explicit when-to-use or when-not-to-use guidance and no named alternatives (e.g., click vs hover, highlight vs hover). The fallback sentence is behavioral, not usage guidance. An agent must infer the use case from the purpose statement alone.

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