browser-mcp

browser_scroll

Scroll a web page at exact coordinates by sending wheel events with vertical and horizontal pixel offsets.

Instructions

Scroll the wheel at (x, y) by dy vertical / dx horizontal pixels.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "x": "<x>",
      "y": "<y>"
    },
    "name": "browser_scroll"
  }
}

Input Schema

Name	Required	Description	Default
`x`	Yes
`y`	Yes
`dx`	No
`dy`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Sep 18, 2026

TDQS

A3.7/5.0

Behavior3/5

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

With no annotations, the description must carry the behavioral disclosure burden. It does state the core behavior (scroll at a point by pixel deltas), but it does not clarify the coordinate system (viewport vs. page), scroll direction sign convention beyond pixel deltas, or what happens if coordinates are out of bounds. This is adequate but not rich.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The entire description is one front-loaded sentence that states the action, location, and units without filler. Every clause adds operational value.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a 4-parameter, no-output-schema action tool, the description covers the core invocation but leaves the coordinate basis and edge-case behavior implied. An agent might call it correctly in a common case, but would not know viewport semantics or whether the wheel event is relative to the current scroll position.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description compensates by naming all four parameters and explaining their roles: x/y as the scroll position and dx/dy as horizontal/vertical pixel amounts. It stops short of describing coordinate space and defaults (already in schema), but it provides meaning the bare integer schema does not.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb ('Scroll') and identifies the exact target ('wheel at (x, y)') plus the units of action (`dy` vertical / `dx` horizontal pixels). This makes the tool's function immediately distinguishable from the other browser action siblings such as browser_click or browser_js.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description states what the tool does but gives no guidance on when to prefer it over alternatives or any prerequisites/context. There is no 'use when...' or 'for other scrolling behavior use...' note, so an agent must infer usage from the tool name alone.

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