Simulates hovering over a page element using a snapshot reference or unique CSS selector to automate pointer interactions and reveal hover-triggered UI states in browser sessions.
Hover over an element.
| Name | Required | Description | Default |
|---|---|---|---|
| pageId | No | Defaults to the active page | |
| target | Yes | Snapshot ref (e12) or unique CSS selector | |
| sessionId | No | Defaults to the active session |
Changes observed during successful MCP inspections.
v2026.10.24Input schema / properties / pageId / descriptionPrevious value: -"Stable page ID; defaults to the session active page"New value: +"Defaults to the active page"Input schema / properties / sessionId / descriptionPrevious value: -"Optional session ID; defaults to this MCP client active session"New value: +"Defaults to the active session"Input schema / properties / target / descriptionPrevious value: -"Snapshot ref such as e12, aria-ref=e12, or a unique CSS selector"New value: +"Snapshot ref (e12) or unique CSS selector"v2026.8.14Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden and provides almost none. It does not explain whether hovering triggers page events, whether the state persists, visibility requirements, or any side effects.
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 front-loaded sentence with no wasted words. It is appropriately terse for a simple browser action, though the terseness contributes to missing usage and behavioral context.
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 low-complexity tool with fully described parameters and no output schema, the description is minimally adequate. It lacks guidance on target validity, page/session defaults, and interaction behavior that would help an agent 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 100%, so the schema already documents pageId, target, and sessionId. The description adds no parameter meaning beyond the schema, but baseline 3 is appropriate when the schema does the heavy lifting.
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 states a specific verb and resource: hover over an element. It is clear what the tool does, but it does not explicitly distinguish itself from sibling interaction tools such as nex_browser_click, nex_browser_mouse_click_xy, or nex_browser_drag.
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 gives no guidance on when to use hover versus other browser interaction tools. It implies a basic hover use case but omits alternatives, prerequisites, or exclusions.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.