Melatonin

A Codex-style desktop app for the pi coding agent.

Melatonin is a secondary-development fork of minghinmatthewlam/pi-gui. It keeps the upstream architecture while using an independent repository and product identity. This repository was initialized from upstream revision eb9a738.

Melatonin gives pi a native home on the desktop: a threaded timeline of your agent sessions, git worktrees per thread, an integrated terminal and inline diff viewer, and multi-agent orchestration — all backed by pi's own session files as the source of truth. It is a UI shell around @earendil-works/pi-coding-agent, not a separate agent runtime: session management, model/auth setup, and agent execution all run through upstream pi.

_{Expanding a tool call, reviewing the diff panel, the integrated terminal, and a theme switch. (higher-quality MP4)}

Screenshots

Thread timeline (dark)	Thread timeline (light)

Inline diff viewer	Integrated terminal

Features

• Threaded timeline — each session renders as a timeline of messages and collapsible tool calls, Codex-style.
• Git worktrees per thread — start a thread in the workspace directly (Local) or in an isolated git worktree so parallel work never collides.
• Multi-agent orchestration — an orchestrator thread can spin up and supervise child worker threads.
• Integrated terminal — a real PTY terminal (via node-pty) docked in the app.
• Inline diff viewer — review changed files in a side panel (toggle with ⌘/Ctrl+D).
• Composer niceties — @-mention files, and paste or drag-and-drop image attachments straight into the prompt.
• Skills & extensions — manage pi skills and extensions from a dedicated view.
• Appearance themes — light and dark, with selectable theme presets.
• Native notifications — get an OS notification when an agent run finishes.
• Session archive — archive threads you're done with to keep the sidebar tidy.
• Multiple providers — connect model providers via OAuth or API key under Settings → Providers.

Install

Melatonin is in public beta for macOS (Apple Silicon) and Linux (AppImage).

From GitHub Releases

Download the latest .dmg (macOS) or .AppImage (Linux) from the Releases page.

On macOS, drag melatonin.app into /Applications and launch it. Releases are signed and notarized. To update, download the newer release and replace the app.

With Homebrew (macOS)

brew tap CBx-2023/tap
brew install --cask melatonin

Update with brew upgrade --cask melatonin. During beta, a Homebrew upgrade may prompt you to re-confirm macOS permissions or Dock placement.

From source

See Development. Building from source is intended for contributors, not as the primary install path.

Quickstart

1. Install Melatonin and launch it.
2. Open Settings → Providers and connect a model provider (OAuth or API key).
3. Add a workspace (a local project folder).
4. Click New thread, pick Local or Worktree, and send your first prompt.

You need valid model/provider authentication that pi supports; Melatonin uses pi's auth and session state, so anything you've already configured with the pi CLI carries over.

Architecture

Melatonin is an Electron app organized around a tight main/preload/renderer boundary, sitting on top of the pi runtime:

• Renderer (apps/desktop/src) — the React UI: timeline, composer, diff panel, terminal, settings. It talks to the main process only through a typed IPC surface.
• Preload (apps/desktop/electron/preload.ts) — the narrow bridge that exposes that IPC surface to the renderer; the renderer gets no broad Node access.
• Main (apps/desktop/electron) — the Node side: windowing, session supervision, worktrees, terminal PTYs, notifications, and persistence.
• packages/pi-sdk-driver — a thin adapter from the desktop app to @earendil-works/pi-coding-agent. It stays close to upstream pi and does not fork or reimplement runtime behavior.
• JSONL session files as the source of truth — pi persists each session as a JSONL transcript on disk; Melatonin reads those files as the authoritative record for closed sessions rather than keeping a divergent copy.

Supporting packages: packages/session-driver (shared session driver types) and packages/catalogs (lightweight workspace/session catalog state).

Development

Requires Node 20+ and pnpm (managed via corepack). pnpm is the supported package manager, and pnpm-lock.yaml is the authoritative lockfile.

corepack enable
pnpm install

Common commands (run from the repo root):

pnpm dev         # run the desktop app in development (electron-vite, hot reload)
pnpm build       # build all workspaces
pnpm typecheck   # type-check all workspaces
pnpm lint        # lint all workspaces
pnpm test        # run each workspace's tests (desktop runs the core E2E lane)

Desktop end-to-end tests use a Playwright + Electron harness and are organized into lanes. The default pnpm test runs the core lane; to run everything:

pnpm --filter @melatonin/desktop run test:e2e:all   # core + live + native

See apps/desktop/README.md for lane details and platform-specific packaging notes. Package a Linux AppImage locally with:

pnpm --filter @melatonin/desktop run package:linux

Repository layout

• apps/desktop — the Electron app (renderer UI + main/preload).
• apps/website — the marketing/landing site.
• packages/pi-sdk-driver — adapter over @earendil-works/pi-coding-agent.
• packages/session-driver — shared session driver types.
• packages/catalogs — workspace/session catalog state.

Contributing

Contributions are welcome — see CONTRIBUTING.md for setup, verification expectations, and the desktop test lanes. Desktop changes are expected to be verified on the real Electron surface, not only by unit tests.

Computer use

Native computer use is not built into Melatonin. Desktop/browser control is available separately through the author's standalone computer-use-mcp server, which any MCP-capable agent can use.

Acknowledgements

• Built on @earendil-works/pi-coding-agent.
• Upstream runtime and ecosystem by earendil-works/pi.
• Original desktop project by minghinmatthewlam/pi-gui.

License

MIT © Matthew Lam