Enhanced ADB MCP Server

by rahulkr

Overview Schema Source Related Servers Discussions Admin

Python

Local

change_screen_size

Adjust Android device screen resolution to test different display sizes for UI development and visual QA workflows.

Instructions

Change screen resolution - useful for testing different screen sizes

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": {
      "width": "<width>",
      "height": "<height>"
    },
    "name": "change_screen_size"
  }
}

Input Schema

Name	Required	Description	Default
`width`	Yes
`height`	Yes
`device_serial`	No

Output Schema

Name	Required	Description	Default
`result`	Yes

Implementation Reference

src/adb_mcp_server/server.py:931-934 (handler)
The main handler function for the 'change_screen_size' tool. It changes the Android device's screen resolution using the ADB 'wm size' command. The function is automatically registered as an MCP tool via the @mcp.tool() decorator.
```
@mcp.tool()
def change_screen_size(width: int, height: int, device_serial: str | None = None) -> str:
    """Change screen resolution - useful for testing different screen sizes"""
    return run_adb(["shell", "wm", "size", f"{width}x{height}"], device_serial)
```

Schema Changelog

Changes observed during successful MCP inspections.

First observedDec 15, 2025

TDQS

B3.1/5.0

Behavior2/5

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. While 'change' implies a mutation, the description doesn't specify whether this requires specific permissions, if changes are reversible, what happens on different devices, or any rate limits. It mentions testing use but lacks operational details.

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 extremely concise with just two phrases that directly address purpose and use case. Every word earns its place with zero redundant information, making it easy to parse quickly.

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?

Given that there's an output schema (which handles return values), no annotations, and moderate complexity (3 parameters with 2 required), the description provides basic purpose and context but lacks important details about behavioral implications, parameter usage, and differentiation from sibling tools. It's minimally adequate but has clear gaps.

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?

Schema description coverage is 0%, so the description must compensate for undocumented parameters. The description mentions 'screen resolution' which implies width and height parameters, but doesn't explain the optional 'device_serial' parameter or provide any format/unit details. It adds minimal value beyond what the schema titles suggest.

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 clearly states the tool's purpose with a specific verb ('change') and resource ('screen resolution'), and provides a use case ('useful for testing different screen sizes'). However, it doesn't explicitly differentiate from the sibling tool 'reset_screen_size', which appears to be a related function.

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 mentions a general use case ('testing different screen sizes') but provides no guidance on when to use this tool versus alternatives like 'reset_screen_size' or 'get_screen_specs'. There are no explicit when/when-not instructions or prerequisites mentioned.

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

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