Scroll a page or a chosen element up, down, left, or right in React Native Web browser automation, with optional pixel amount and CSS selector.
Scroll the page or a specific element
| Name | Required | Description | Default |
|---|---|---|---|
| amount | No | Amount to scroll in pixels (default: 300) | |
| selector | No | Optional: CSS selector of element to scroll within | |
| direction | Yes | Direction to scroll |
Changes observed during successful MCP inspections.
v2.0.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description must carry the full behavioral burden. It doesn't disclose whether scrolling is reversible, how it interacts with dynamic loading, or whether it triggers scroll events that might affect other state. For a mutation-adjacent action, this is a notable gap.
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, efficient sentence that front-loads the action and scope. Every word earns its place, with no redundancy.
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?
Given the tool's relative simplicity and full schema coverage, the description is minimally adequate. However, without annotations or output schema, it misses opportunities to clarify return values or side effects, leaving some ambiguity for an agent.
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%: each parameter (amount, selector, direction) has a clear description in the schema. The description adds nothing beyond what the schema already provides, so the baseline of 3 is appropriate.
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 (Scroll) and resource (page or a specific element), clearly distinguishing it from siblings like rnw_navigate or rnw_click. An agent can immediately understand this is a viewport-scrolling operation.
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 provides no guidance on when to use this tool versus alternatives such as rnw_evaluate or rnw_press_key. While the verb is clear, there's no mention of prerequisites or typical scenarios.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.