mcp-android-emulator

scroll

Navigate the Android emulator screen by moving it up, down, left, or right. Specify the pixel amount to control the distance.

Instructions

Scroll the screen in a direction

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": {
      "direction": "<direction>"
    },
    "name": "scroll"
  }
}

Input Schema

Name	Required	Description	Default
`amount`	No	Scroll amount in pixels (default: 500)
`direction`	Yes	Direction to scroll

Schema Changelog

Changes observed during successful MCP inspections.

First observedv2.0.0Aug 2, 2026

TDQS

B3.1/5.0

Behavior2/5

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

Since no annotations are provided, the description must carry the full burden of behavioral disclosure. It only states the action and direction, but does not explain how scrolling behaves (e.g., default amount, whether it scrolls the entire viewport or a focused element, or whether it is a continuous or discrete scroll). This is very thin disclosure.

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 description is a single, front-loaded sentence that immediately states the verb and target. It contains no fluff or repeated information, making it maximally concise.

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 simple tool with only two parameters and no output schema, the description plus schema may be minimally adequate for invocation. However, the absence of usage guidelines and behavioral context means the description is not fully complete for selecting the right tool among many similar UI interaction siblings.

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

Parameters3/5

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

The input schema covers both parameters (direction with enum, amount with default 500) and has 100% description coverage. The description adds no param-specific meaning 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.

Purpose4/5

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

The description 'Scroll the screen in a direction' clearly identifies the action (scroll), target (screen), and a modifier (direction). However, it does not explicitly distinguish from sibling tools like swipe or scroll_to_text, so it falls short of a full 5.

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 provides no guidance on when to use this tool versus alternatives such as swipe, drag, or scroll_to_text. There are no exclusions, prerequisites, or context hints, leaving the agent without decision support.

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