ADB MCP Server

by LLL-404

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TypeScript

Local

Get Current Foreground App

adb_current_app

Read-onlyIdempotent

Retrieve the package name and activity of the currently foreground app on an Android device.

Instructions

Get the package name and activity of the foreground app.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "adb_current_app"
  }
}

Input Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0May 26, 2026

TDQS

A3.8/5.0

Behavior3/5

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

Annotations already declare readOnlyHint, destructiveHint, and idempotentHint, so the description carries a lower burden. It adds that the tool returns 'package name and activity,' but does not mention edge cases (e.g., no foreground app) or output format. This is adequate but not enhanced beyond the annotations.

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 sentence that is front-loaded with the action and result. Every word contributes to understanding, with no wasted text.

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

Completeness4/5

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

Given no parameters and annotations covering safety, the description covers the core function. However, the output format is unspecified (e.g., 'com.example.app/.MainActivity'), and potential edge cases (e.g., no app in foreground) are not mentioned. With no output schema, these details would improve completeness.

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?

The input schema has zero parameters, so schema coverage is 100%. The description need not explain parameters, and it adds no extra meaning for them. The baseline score for no parameters is 4, and the description meets that.

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 clearly states the tool retrieves 'the package name and activity of the foreground app.' It uses a specific verb ('get') and resource ('foreground app'), and distinguishes it from siblings like adb_app_info (info on specific app) or adb_list_packages (list all packages).

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 does not provide guidance on when to use this tool versus alternatives, such as adb_app_info or adb_ui_tree. It merely states what it does without context on prerequisites, limitations, or typical use cases.

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