Scroll a page by pixel offsets or bring a specific element into view using its ref, selector, or visible text.
Scroll the page by deltaY/deltaX pixels, or scroll an element (ref/selector/text) into view.
| Name | Required | Description | Default |
|---|---|---|---|
| ref | No | Element ref from browser_snapshot, e.g. "e12" | |
| text | No | Visible text to match (alternative to ref) | |
| deltaX | No | ||
| deltaY | No | ||
| selector | No | CSS or Playwright selector (alternative to ref) |
Changes observed during successful MCP inspections.
v1.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare the mutation/safety profile (readOnlyHint=false, destructiveHint=true, idempotentHint=false), and the description adds nothing behavioral on top — no note on prerequisites (page must be loaded), what happens if the ref/text/selector is not found, or whether the scroll delta is bounded. For a state-changing tool with no output schema this is a real 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?
A single tight sentence with both use modes front-loaded and no filler. It could have been split into a target-selection clause and a delta clause for faster scanning, but it wastes nothing.
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?
Five optional parameters, no output schema, and the description only broadly names both modes without covering default deltas, overloaded-parameter precedence, or failure behavior when a target is not found. It is minimally adequate but not complete for a tool with this many knobs.
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 60%, and the description contributes the useful unit detail that deltaY/deltaX are in pixels, which the schema omits. However it does not explain precedence when ref, text, and selector are all supplied, nor the deltaY=600 default behavior, so it only partially compensates for the coverage gap.
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) plus both targeting modes (pixel delta vs element into view), so the agent knows exactly what the tool does. It does not differentiate itself from the near-identical sibling chrome_scroll or from other viewport-affecting tools, which keeps it from a 5.
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?
No when-to-use guidance at all: nothing about when to scroll versus calling browser_snapshot, browser_wait_for, or a click that auto-scrolls. No prerequisites or sequencing hints are given.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.