BranchLab

A desktop app for driving OpenCode across many isolated workspaces at once. BranchLab creates a git worktree per task, runs an OpenCode server in each, and gives you one window to chat with the agent, review its diffs, browse files, and manage config — without juggling terminals or stepping on your main checkout.

Status: early MVP. macOS-only for now (the "open in editor/terminal/Finder" integrations shell out to open). Windows/Linux support is a planned portability pass.

How it works

┌──────────┐      Tauri IPC       ┌─────────────────────┐     spawns      ┌──────────────┐
│  React   │ ───────────────────► │   Rust backend      │ ──────────────► │  opencode    │
│  (UI)    │ ◄─────────────────── │ (registry, git,     │                 │  server(s)   │
└──────────┘                      │  servers, config)   │ ◄───────────────┴──────────────┘
     │                            └─────────────────────┘   HTTP + SSE (from the UI directly)
     └── talks to each workspace's opencode server over HTTP/SSE for chat

• The Rust backend owns all filesystem, git, and process work, and persists a project/workspace registry. Every operation is a typed Tauri command.
• The React frontend renders the UI and talks to each workspace's OpenCode server directly over HTTP + Server-Sent Events for chat and live updates.
• Each workspace is a git worktree stored under the app data dir, with its own on-demand OpenCode server (idle servers are reaped automatically).

Features

• Projects & workspaces — add a git repo, spin up worktree-backed workspaces off any branch.
• Agent chat — streaming OpenCode chat per workspace, with model selection and context-window tracking.
• Changes view — live unified/split diffs of the working tree, with per-file discard and "mark viewed".
• File browser & viewer — a file tree per workspace plus a read-only, line-numbered in-app file viewer (handles binary and oversized files).
• Config panel — view and edit global/project OpenCode config and restart the server to apply it.
• Fleet dashboard — an overview of every workspace and its diff stats.

Prerequisites

BranchLab drives tools you install yourself (it does not bundle them):

• opencode on your PATH
• git
• Node.js 20.19+ (or 22.12+) and Rust for development

On launch BranchLab probes for opencode and git; if either is missing it shows an onboarding screen instead of the app.

Development

npm install          # install frontend deps
npm run tauri dev    # run the desktop app with hot reload

Other commands:

npm run build        # type-check (tsc) + production frontend build
npm test             # run frontend unit tests (Vitest)
npm run test:watch   # Vitest in watch mode

cd src-tauri && cargo test    # run Rust unit tests
cd src-tauri && cargo build   # build the backend

Project layout

src/                     React frontend
  components/            UI (Chat, Sidebar, WorkspaceView, center/, layout/, ui/)
  hooks/                 keyboard shortcuts, native desktop behaviors
  lib/                   api.ts (IPC wrappers), opencode.ts (HTTP client),
                         types.ts, diff.ts, themes.ts
src-tauri/src/           Rust backend
  commands.rs            Tauri IPC command surface
  project.rs             project/workspace registry (JSON persisted)
  server.rs              OpenCode server lifecycle + idle reaper
  git.rs                 git CLI wrappers (worktrees, diff, file read)
  config.rs              OpenCode config read/write
  env.rs                 PATH probe for opencode/git

See AGENTS.md for conventions and a guide to extending the codebase.