Dispatch a single mouse wheel scroll event on a target page to simulate user scrolling and trigger scroll-based actions.
Dispatch a wheel event. Raw page.mouse.wheel — single event, not multi-step.
| Name | Required | Description | Default |
|---|---|---|---|
| delta_x | No | Horizontal scroll delta in pixels (default: 0) | |
| delta_y | Yes | Vertical scroll delta in pixels (positive = scroll down) | |
| target_id | Yes | Target ID from interceptor_browser_launch |
Changes observed during successful MCP inspections.
v3.5.3Input schema / properties / target_id / descriptionPrevious value: -"Target ID from interceptor_browser_launch or interceptor_camoufox_launch"New value: +"Target ID from interceptor_browser_launch"v3.3.2Input schema / properties / target_id / descriptionPrevious value: -"Browser target ID from interceptor_browser_launch"New value: +"Target ID from interceptor_browser_launch or interceptor_camoufox_launch"v2.3.0Input schema / properties / duration_msRemoved value: -{
- "default": 400,
- "description": "Total scroll duration in ms (default: 400)",
- "type": "number"
-}Input schema / properties / target_id / descriptionPrevious value: -"Chrome target ID from interceptor_chrome_launch"New value: +"Browser target ID from interceptor_browser_launch"v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are present, so the description carries the disclosure burden, and it does disclose the key behavior: exactly one raw wheel event is dispatched, not a smooth multi-step scroll. It is honest about the primitive nature and does not oversell humanization.
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 short clauses with no filler; the core action is front-loaded and the 'raw ... single event' qualifier earns its place by setting expectations. It is appropriately sized for the tool's 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?
For a low-complexity event dispatcher with fully documented parameters, the description covers the essential context: what it sends, and that it is not a multi-step humanized sequence. It doesn't spell out return/error behavior, but that is minor at this complexity.
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%, with delta_x, delta_y, and target_id all described in the schema, so the description need not add parameter detail. The description itself adds no parameter-specific meaning beyond calling it a wheel event.
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?
It states exactly what it does with a specific verb and resource ('Dispatch a wheel event') and adds that it is the raw page.mouse.wheel primitive rather than a multi-step action. This distinguishes it from the humanizer_move sibling, though it does not name the sibling explicitly.
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 guidance about when to use this tool instead of alternatives; 'single event, not multi-step' implies a contrast with higher-level scrolling but never names humanizer_move or states selection conditions. An agent is left to infer usage from the name and sibling list.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.