browser_hover

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

Discloses far more than the annotations: the synthetic-event caveat that CSS :hover styles do not apply, the ~6 s timeout failure message when no preview pane runs, and the credential-page access refusal. These are exactly the behavioral traits an agent needs and cannot derive from structured fields.

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 the action and its purpose, then the return values, caveat, and prerequisites. Every sentence carries distinct, load-bearing information with no filler.

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 output schema, the description still communicates return values (hovered / not found), prerequisites (preview open with agent access), the failure mode, and the credential-access constraint. Nothing an agent needs to invoke it correctly is missing.

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 coverage is 100%, so the schema already documents the selector parameter and its first-match semantics. The description adds no additional parameter detail beyond what the schema provides, 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 (hover) and resource (an element in the preview) and explains the intent — open a menu or tooltip before inspecting it. This clearly separates it from browser_click and browser_dom without needing to open a schema.

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?

Gives a concrete when-to-use condition: to reveal a menu or tooltip ahead of inspection. It does not explicitly name a sibling alternative (e.g. when to prefer browser_click), so it stops short of full routing guidance, but the context is clear.

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