rn-device-mcp

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List Android devices

android_devices

Read-only

Lists connected Android emulators and USB devices known to adb, with serial and state, so you can identify which device to target for React Native or Expo tasks.

Instructions

Lists emulators and USB devices known to adb, with serial and state.

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": "android_devices"
  }
}

Input Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Nov 4, 2026

TDQS

A3.7/5.0

Behavior3/5

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered without the description's help. The description adds that results come from adb's device table and include serial and state, which is modest but real added context; it says nothing about behavior when no devices are attached or when adb is unavailable.

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?

A single short sentence that front-loads the verb and scope, with no filler or redundancy. Every clause (adb source, device types, returned fields) carries information.

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?

For a zero-argument listing tool with no output schema, the description gives the essential return shape (serial and state), which is what an agent needs to parse results. It stops short of covering failure modes or the exact state vocabulary (e.g. device vs offline vs unauthorized), which would fully close the gap.

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 tool takes zero parameters, so the schema has nothing to explain and the baseline of 4 applies. The description correctly implies the call is unfiltered and takes no arguments.

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?

States a specific verb and resource ("Lists emulators and USB devices known to adb") and even names the fields returned (serial, state). The android_ prefix plus the adb reference clearly separates it from the iOS counterpart ios_simulators, though the description never names that sibling explicitly.

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

Usage Guidelines3/5

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

Usage is only implied: an agent can infer this is the discovery step before android_launch_app, android_screenshot, or android_reverse_metro, but the description never says so. There are no explicit when-to-use or when-not-to-use conditions and no mention of prerequisites such as a running adb server.

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