browser_hover

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

With no annotations, the description carries the full burden and does substantial work: it discloses the 'covered' failure case, the covered_by field, that nothing is sent when coverage is detected pre-move, and that maybe_landed:true is returned when something occludes mid-movement. Missing only success-path detail, but the failure/ordering semantics are unusually well disclosed.

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?

Purpose and selector support are front-loaded in the first two sentences. The final sentence is a dense run-on (awkward phrasing like 'the page may already reacted'), but it earns its length by conveying non-obvious ordering semantics.

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?

With no annotations and no output schema, the description compensates by describing the shape of the failure response (ok:false, error 'covered', covered_by, maybe_landed). An agent has enough to call and interpret results, though success-return behavior is left implicit.

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% and both parameters carry descriptions, so the baseline is 3. The description's 'Supports CSS and text selectors' largely restates the selector schema entry and adds no format syntax or duration guidance beyond it.

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 precise verb (hover) plus resource (element) and names the concrete outcomes it produces (tooltips, dropdown menus, hover states). This clearly distinguishes it from the many click/keyboard siblings such as browser_click and browser_double_click.

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 implies when to use it by listing the UI behaviors it triggers, but offers no explicit when-not guidance and names no alternative sibling (e.g. browser_click for actual clicks). Usage is inferable but not spelled out.

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