Codey

Codey is a small Neovim client. Neovim remains the editor: it owns the buffers, modes, mappings, selections, cursor, plugins, and undo history. Codey connects to Neovim's native MessagePack-RPC endpoint and projects its line-grid UI into a platform renderer. Android can either start the bundled local NeoVim proof of concept or connect to an existing remote TCP endpoint.

The repository contains two end-to-end clients over the same shared protocol and editor-state packages:

apps/
  desktop/       Electron client with an HTML canvas renderer
  android/       Expo development client for Android tablets
packages/
  transport/     Platform-neutral byte-stream contract and Node TCP adapter
  msgpack-rpc/   Streaming MessagePack-RPC client
  nvim-session/  Typed Neovim UI facade
  editor-core/   Platform-neutral redraw reducer and grid state

The Android path uses a Skia renderer, an Android IME view, and local Expo Kotlin modules for TCP and the bundled process. Phones remain installable, but a window whose shortest side is below 600dp, or is not wider than it is tall, only shows the unsupported-device explanation and cannot open a Neovim session. Supported landscape windows place the action pad in a scrollable right-hand rail. Ordered base groups keep fixed rail-capacity envelopes. A configured group action can temporarily replace only its invoking slot without moving siblings or changing scroll extent, while Cmd, Leader, Search, Window, and Code remain whole-page navigation. The header distinguishes the page path from the one active transient cluster. The primary design target remains a 12–14-inch tablet. A completed editor tap is forwarded through Neovim's native mouse API to position the cursor; the configured Keyboard interaction opens the Android software keyboard.

Development environment

The checked-in Nix flake is the supported host environment:

nix develop
pnpm install

It provides Node.js, pnpm, Neovim, the Electron runtime libraries, and the Android host toolchain: JDK 17, Watchman, ADB/platform tools, EAS CLI, Android platform and build-tools 36, NDK 27.1.12297006, and CMake 3.22.1. Android SDK licences are accepted declaratively by the flake. npm packages and Maven artifacts are still resolved by pnpm and the Gradle wrapper from the checked-in project metadata.

Desktop client

Start a local endpoint and the Electron client:

nvim --clean --headless --listen 127.0.0.1:6666
pnpm dev

Enter 127.0.0.1 and 6666 in the connection bar. Once connected, click the editor canvas and use Neovim normally.

Android tablet development client

Use a physical Android tablet with developer options and USB debugging enabled. The device and development host must also be able to reach each other on a trusted private LAN.

Check the USB connection, then build and install the development client:

adb devices
pnpm android:install

For later JavaScript/TypeScript iterations, start Metro for the installed development client with:

pnpm android:metro

The app is Android-only and requires a landscape tablet window. Use the Remote tab with the development host's private-LAN address; 127.0.0.1 on the tablet means the tablet itself. Start Neovim on that concrete host address, for example:

nvim --clean --headless --listen 192.168.1.20:6666

The personal arm64 Android 11+ proof-of-concept APK can instead start its own NeoVim process. Build it with pnpm android:poc, then select Local, grant Android all-files access, and choose an existing writable workspace and Neovim config folder before connecting. See the bundled NeoVim POC guide for its scope, binary provenance, and the work intentionally deferred before F-Droid.

Changes to Expo native configuration, including orientation support, or native modules require a clean native regeneration and reinstall. The installed APK does not pick up these changes from Metro alone:

pnpm android:prebuild
pnpm android:install

The generated apps/android/android/ tree is disposable and ignored. The local Expo modules under apps/android/modules/ are source-controlled.

See the Android client guide and host setup for physical-device and LAN details.

Verification

Run the complete desktop and Android verification from the Nix shell:

nix develop -c pnpm check

This runs TypeScript checks, shared Vitest tests, Android Jest tests, the production Electron build, Expo Doctor, an Android Metro export, a clean native prebuild, Kotlin unit tests, and both debug and release assembly. Generated APKs are under apps/android/android/app/build/outputs/apk/.

Individual Android checks are also available:

pnpm android:doctor
pnpm android:bundle
pnpm android:test
pnpm check:android:native

With a clean Neovim endpoint already listening on loopback, the optional desktop live test exercises the full TCP → RPC → session → redraw-reducer path:

CODEY_NVIM_PORT=6666 pnpm test:live-nvim

Prototype security boundary

Treat the Neovim RPC port like shell access to the host account. This prototype has no authentication or encryption. Do not expose it to the internet, add router port forwarding, bind it to 0.0.0.0, or use it on an untrusted network. Restrict the port to the tablet address or trusted subnet with the host firewall where practical.

Local mode removes the network endpoint, not Neovim's command power. A config folder is required before connecting. Neovim starts with --clean when that folder has no init.lua; otherwise that Lua and normal config runtime files execute automatically. Neither mode is a sandbox: commands, Lua, system(), and :! run with the Android app UID and can access files covered by the app's all-files grant. Use trusted Local config folders, files, and Action Pad configurations.

See the architecture notes for the component boundaries and current limitations. Codey source is available under Apache-2.0; bundled proof-of-concept dependencies are listed in third-party notices.