MCP Phone Use

Lire en français

Gives an MCP-compatible AI assistant real, secure access to an Android phone — perception (reading the screen, taking a screenshot) and action (tap, swipe, type text, launch apps) — without ever needing ADB or a local computer, neither for everyday use nor for debugging.

  

Self-hosted. This isn't an MCP server you spin up locally with a single command. You need to host the relay yourself (Python, public HTTPS URL). Expect 30-60 minutes for a first deployment — see Installation.

Ready-to-use APKs: latest release — no need to compile the Android app yourself, only the relay still needs deploying.

What it does

Three tools exposed via MCP:

• get_ui_tree — reads the accessibility hierarchy of the foreground app (text, clickable elements, position), regardless of which app is active
• device_action — tap, swipe, type_text, key (back/home/recents/notifications), launch_app
• get_screen — real screenshot (JPEG), for anything accessibility alone can't see (visual rendering, WebView content, poorly-accessible apps)

The first two rely on an AccessibilityService; the third on MediaProjection (armed separately, system consent prompt on every session, never bundled with the connection itself).

Architecture

MCP-compatible AI assistant (Claude, or any other MCP client)
        │  OAuth 2.1 + PKCE, Streamable HTTP
        ▼
   MCP relay (your own hosting)
   auth server + resource server
        ▲
        │  outbound connection, challenge-response (Keystore key)
   Android app (MCP Phone Use)
   AccessibilityService + MediaProjection

The phone connects outbound to the relay — no ADB, no NAT traversal, no open port on the phone's side. Full detail in docs/architecture.md.

Security

• Double lock — no tool responds unless both conditions are met: valid OAuth session and app connected on the phone's side
• No static token — the app proves its identity through a cryptographic signature (Android Keystore key pair, non-exportable) on every connection, never through a secret sent in the clear
• Rate-limiting — bounded attempt count, per IP, on entry points with a guessable secret (login, enrollment) — tested under a real attack, see SECURITY.md
• Non-bypassable human consent — the assistant can bring the user to a system consent popup (accessibility, screen capture), but never taps it itself; the final gesture always stays human, by design, not by technical limitation

Full detail on the security model, the tests actually performed, and the known limitations: SECURITY.md.

Installation

1. Deploy the relay

The relay (relais/) needs to run continuously, reachable from the internet over HTTPS — the phone connects to it outbound, and Claude calls it like any regular MCP server. A Dockerfile is provided for generic deployment on any hosting (VPS, cloud pod...). See CONTRIBUTING.md for the full commands, or relais/README.md for detail without Docker.

2. Install the Android app

The app is distributed outside the Play Store, which by default triggers Android's "Restricted Settings" block, preventing accessibility from being enabled. Clean workaround, no ADB needed: a dedicated installer using PackageInstaller in session mode (the same mechanism Play Store/F-Droid use), which installs MCP Phone Use with enough trust status to avoid that block.

1. Download the installer from the latest release, sideload directly
2. Open the installer (the main APK's URL is already pre-filled), tap "Download and install"
3. Open the app, enter the pairing code given by your assistant (single-use, 10 min)
4. Enable accessibility and, if needed, arm screen capture

Status

Complete groundwork, validated under real conditions: OAuth 2.1/PKCE, double lock, challenge-response, rate-limiting, wake lock (keeps the screen from turning off during an active capture), built-in crash reporter (Thread.UncaughtExceptionHandler + ApplicationExitInfo, no ADB needed).

Remaining backlog: persistence of the device registry on the relay side (currently in-memory, lost on every process restart).

License

MIT — free to use, modify, and redistribute.