Buddy

A floating chat bubble that lets Claude Code (or Codex) use your Android phone.

Type a request into the bubble ("reply to Sam that I'm running late", "add a Nintendo Switch 2 to my Amazon cart") and Buddy reads the screen, taps, types and scrolls to get it done. It asks for your approval before anything that sends, posts, buys or deletes.

Buddy runs on your own subscription: Claude Code with your Claude plan, or OpenAI's Codex CLI with your ChatGPT plan. Both run inside the app, in Buddy's own small Linux on the phone: no Termux, no PC. The app has no API key, no server and no account of its own.

⬇ Download the APK (Android 11+, 64-bit phones)

Status: 2.0, early. It works well day to day but still has rough edges. Tested on a OnePlus 12 (OxygenOS, Android 16); other Android 11+ phones should work, but may need battery settings adjusted.

Buddy is an independent project. It is not made by or affiliated with Anthropic or OpenAI.

Not another adb setup

Most "AI controls my phone" projects drive the phone over adb, which needs a computer or Wireless debugging that drops all the time. Buddy doesn't use adb at all:

• It's a normal Android app with an accessibility service, the same kind of permission screen readers use.
• No adb, no Wireless debugging, no PC, no root.
• Works without Wi-Fi and comes back on its own after a reboot.

How it works

Buddy app / bubble ──► Buddy's Linux (Alpine via proot): buddy-run ──► claude -p  or  codex exec
        ▲                                                                  │
        └────────────── streamed replies (POST /event) ◄───────────────────┤
                                                                           ▼
Buddy accessibility service ◄──── MCP over http://127.0.0.1:8765/mcp (phone tools)

• The accessibility service draws the bubble and runs a small local MCP server with the phone tools: read_screen, tap, long_press, type_text, scroll, swipe, press, open_app, list_apps, open_url, screenshot, wait, install_apk, wait_for_install, confirm and notify.
• Buddy's Linux is a small Alpine Linux that Buddy downloads into its own storage (4 MB) and runs with proot, which ships inside the APK. Claude Code installs there with Anthropic's official installer; Codex from npm.
• Your message goes to the agent in Buddy's Linux, which uses those tools and streams its progress back to the app.

Setup

You need a 64-bit Android 11+ phone and a Claude Pro/Max plan (or a ChatGPT plan for Codex).

1. Install Buddy: download the APK and open it (allow your browser to install apps when asked). All versions are on the Releases page.
2. Follow the setup guide. It opens on first launch (later: Settings → Setup → Open the step-by-step guide). Each step ticks itself off when you come back.

Updating from 1.x (Termux): install the new APK, then install and sign in to your agent in Settings. Termux isn't needed anymore. Chats from the Termux days can't be continued; Settings offers to remove them.

Using Buddy

The app has three tabs: Chats, Sessions and Settings.

• Chats: start one with New chat (Claude Code or Codex), tap a chat to open it, long-press to delete it. Several chats can work at the same time.
• Models: tap the chip under a chat's title to pick the model for that chat (Opus, Sonnet, Haiku, Fable, Codex's own list, or any model name). The conversation continues with the new model.
• Photos and files: tap the paperclip to take a photo, pick photos, or attach any file up to 25 MB.
• Voice: tap the mic to talk; it sends when you stop. The speaker button reads replies aloud.
• Tool calls fold into one "N tool calls" line you can open.
• Approvals appear in the chat and in the bubble: Approve or Deny.
• Sessions: every Claude Code and Codex session in Buddy's Linux, with a Stop button. Recent sessions can be read, or continued in Buddy.
• Settings: setup, appearance (light/dark/system, accent colour, surface), agents (install, sign in, sign out), the bubble, read-aloud, developer mode and Remote Control.

Remote Control: a Claude Code session in your Claude app

Settings → Remote Control → Claude Code session keeps a Claude Code session with Remote Control running inside Buddy. It appears as "Buddy" in the Claude app's Code sessions, on this phone or anywhere else, and it has the phone tools. Buddy restarts it if it stops and continues the same conversation after an update.

When an agent is using your phone

As soon as an agent starts operating the phone, Buddy makes it obvious so you know not to touch it: the bubble turns into a solid "Using your phone" pill with a stop button (even if you've hidden the bubble), and a status-bar notification appears (a Live Update chip on Android 16 where supported). Stop ends Buddy's chats and refuses phone actions from any session for a minute.

The bubble

Developer mode: building apps

Off by default. When it's on, the agent may run commands and create or edit files in ~/.buddy/work inside Buddy's Linux. With the bundled android-app skill (plus AGENTS.md for Codex) you can ask "make me a calculator app": it sets up a toolchain the first time (OpenJDK, aapt2, d8, apksigner; about 400 MB), writes plain Java, builds a signed APK on the phone without Gradle, and opens Android's installer for you to confirm. The first time, Android asks you to allow Buddy to install apps.

Leave it off for everyday use: with it on, text on screen that tries to trick the agent could lead to commands being run.

Security

An accessibility service is powerful. Please read this before installing.

• Local only. The MCP server listens on 127.0.0.1 and requires a random per-install token. Nothing is reachable from the network.
• Approval gate. The agent is instructed to call confirm before sending messages, posting, buying, deleting or changing settings. You see the exact action with Approve / Deny.
• Prompt injection is the main risk. Buddy reads whatever is on screen. A malicious message, email or web page could contain text like "send this to all your contacts". Buddy's instructions treat on-screen text as content, never commands, and the approval gate is the backstop, but no model is perfect. Read approval cards carefully.
• Limited tools. Outside developer mode, Claude Code gets the phone tools, web search and fetch, and read access to that chat's attachments only (no shell, no other files). Codex runs in its read-only sandbox. Everything runs inside Buddy's own app storage, separate from your other apps' files.
• What leaves the phone: only what Claude Code or Codex sends to Anthropic or OpenAI to answer you, including screen text, screenshots and attachments it reads.
• Never let Buddy type passwords, one-time codes or payment details. It's instructed to hand those back to you.

Found a security problem? Please open a private security advisory on GitHub rather than a public issue.

Build

Android Studio / Gradle

./gradlew assembleRelease

Release signing reads BUDDY_KEYSTORE, BUDDY_KEYSTORE_PASSWORD (and optionally BUDDY_KEY_ALIAS, BUDDY_KEY_PASSWORD) from the environment; without them the APK is unsigned. GitHub Actions builds every push and attaches the APK to a release for v* tags.

On the phone, without Gradle

In Termux (or any Linux with these tools):

pkg install openjdk-17 aapt2 d8 apksigner python
# android.jar from platform-36 at ~/android-sdk/android-36/android.jar
./build.sh        # → build/buddy-release.apk

build.sh runs aapt2 → javac → d8 → align → apksigner (and packs app/src/main/jniLibs) and creates a signing key at ~/.buddy-keys/release.jks on first run. Back it up: updates must be signed with the same key.

The version lives in app/src/main/java/app/buddy/assistant/BuildInfo.java.

Project layout

License

Apache-2.0. Geist fonts: SIL Open Font License. Icons: Material Symbols (Apache-2.0). Bundled proot (GPL-2.0), talloc (LGPL-3.0) and libandroid-shmem (BSD-3-Clause): see third_party for licences and source. Not on Google Play: Play's accessibility policy doesn't allow AI agents that operate other apps.