Arbor

Arbor is a fully native app for agentic coding built with Rust and GPUI. It gives you one place to manage repositories, issue-driven worktrees, embedded terminals, managed processes, diffs, PR context, AI coding agent activity, and a shared daemon that also powers Arbor's web UI, CLI, and MCP server.

Why Arbor

• Fully native desktop app, UI and terminal stack included, optimized for long-running local workflows
• One daemon-backed model for the desktop app, web UI, CLI, and MCP server
• Built for parallel coding sessions across local repos, issue queues, and remote outposts

Core Capabilities

Repositories, Worktrees, and Issues

• List, create, and delete worktrees across multiple repositories
• Create managed worktrees directly from GitHub or GitLab issues
• Preview sanitized worktree names, branch names, and target paths before creation
• Repo-local branch naming rules via [branch] in arbor.toml
• Delete confirmation with unpushed commit detection
• Optional branch cleanup on worktree deletion
• Worktree navigation history (back/forward)
• Last git activity timestamp per worktree
• Automatic issue linking to existing branches and open PRs / MRs

Embedded Terminal, Processes, and Tasks

• Built-in PTY terminal with truecolor and xterm-256color support
• Multiple terminal tabs per worktree
• Experimental embedded libghostty-vt engine behind a compile-time feature flag, used by default when available
• Persistent daemon-based sessions (survive app restarts)
• Session attach/detach and signals (interrupt/terminate/kill)
• Managed processes from both Procfile and arbor.toml
• Process restart state, memory metrics, and terminal-session linkage
• Scheduled [[tasks]] from arbor.toml, with optional Claude or Codex triggers
• Bell-aware terminal activity and completion notifications

Diff, PR, and Review Context

• Side-by-side diff display with addition/deletion line counts
• Changed file listing per worktree
• File tree browsing with directory expand/collapse
• Multi-tab diff sessions
• PR summary and detail cards in the changes pane
• Native inline PR comment actions and review-comment refresh support

Agent Chat

• Interactive chat sessions with ACP agents (Claude, Codex, Pi, Gemini, and more via acpx)
• OpenAI-compatible provider support: Ollama, LM Studio, OpenRouter, OpenAI, and any /v1/chat/completions endpoint
• Streaming responses via SSE for OpenAI-compatible providers and JSONL for ACP agents
• Automatic model discovery: probes /v1/models at startup for configured providers
• Model selector with per-provider sections and distinct icons (ACP vs API)
• Provider configuration via ~/.config/arbor/config.toml [[providers]] sections
• Session persistence across daemon restarts
• Token usage tracking and display

AI Agent Visibility

• Detects running coding agents: Claude Code, Codex, OpenCode
• Working/waiting state indicators with color-coded dots
• Real-time updates over WebSocket streaming in both the desktop and web UI
• Legacy session compatibility and targeted clear events for long-lived daemon sessions

Remote Daemon and Companion Binaries

• arbor-httpd serves the remote daemon API and bundled web UI
• arbor-cli exposes daemon-backed health, repo, worktree, terminal, process, and task commands
• Dedicated arbor-mcp binary backed by Arbor's daemon API
• Structured MCP tools for repositories, worktrees, terminals, processes, tasks, and agent activity
• MCP resources for daemon snapshots and prompts for common Arbor workflows
• Supports ARBOR_DAEMON_URL and ARBOR_DAEMON_AUTH_TOKEN for remote authenticated daemons
• Create and manage remote worktrees over SSH
• Multi-host configuration with custom ports and identity files
• Mosh support for better connectivity
• Remote terminal sessions via arbor-httpd
• Outpost status tracking (available, unreachable, provisioning)
• Optional Symphony runtime endpoints when the feature is enabled

UI and Config

• Automatic PR detection and linking per worktree
• Git actions in the UI: commit, push
• Three-pane layout across arbor-gui and arbor-web-ui
• Command palette coverage for actions, repos, worktrees, issues, presets, and task templates
• Resizable panes, collapsible sidebar, desktop notifications
• 38 themes shared between the desktop app and web UI, with live sync when switching themes
• Branch-aware window titles and daemon / rate-limit status polish
• TOML config at ~/.config/arbor/config.toml with hot reload

Install

Homebrew (macOS)

brew install penso/arbor/arbor

Prebuilt Binaries

Download the latest build from Releases. Release bundles ship the desktop app plus arbor-httpd, arbor-mcp, and arbor-cli.

Quick Start from Source

git clone https://github.com/penso/arbor
cd arbor
just run

To run the MCP server against a local dev daemon:

just run-mcp

Documentation

The live docs site is available at penso.github.io/arbor/docs. The in-repo mdBook sources live under docs/src, and you can build them locally with:

just docs-build

Crates

Crate	Description
arbor-benchmarks	CodSpeed and local benchmark targets
arbor-cli	CLI for Arbor's daemon API (arbor-cli binary)
arbor-daemon-client	Typed client and shared API DTOs for arbor-httpd
arbor-core	Worktree primitives, change detection, agent hooks
arbor-gui	GPUI desktop app (arbor binary)
arbor-httpd	Remote HTTP daemon (arbor-httpd binary)
arbor-mcp	MCP server exposing Arbor via stdio (arbor-mcp binary)
arbor-mosh	Mosh transport for remote outposts
arbor-ssh	SSH transport for remote outposts
arbor-symphony	Optional workflow orchestration runtime
arbor-terminal-emulator	Embedded terminal engine glue and Ghostty integration
arbor-web-ui	TypeScript dashboard assets + helper crate

Repo Config

Repo-local behavior is configured with <repo>/arbor.toml. Arbor currently reads repo presets, managed processes, worktree scripts, scheduled tasks, branch naming rules, agent defaults, and notification routing from that file.

Example:

[[presets]]
name = "Review"
icon = "R"
command = "codex --prompt-file .arbor/tasks/review.md"

[[processes]]
name = "web"
command = "npm run dev"
working_dir = "app"
auto_start = true
auto_restart = true
restart_delay_ms = 2000

[scripts]
setup = ["cp .env.example .env"]
teardown = ["rm -f .env"]

[branch]
prefix_mode = "github-user"

[agent]
default_preset = "codex"
auto_checkpoint = true

[notifications]
desktop = true
events = ["agent_started", "agent_finished", "agent_error"]
webhook_urls = ["https://example.com/hook"]

[[tasks]]
name = "triage-prs"
schedule = "0 */30 * * * * *"
command = "./scripts/triage-prs"
enabled = true

[tasks.trigger]
on_exit_code = 0
on_stdout = true
agent = "codex"
prompt_template = "Review this output and prepare a follow-up plan:\n\n{stdout}"

Task templates for the command palette default to <repo>/.arbor/tasks/*.md.

CLI

Arbor also ships arbor-cli for daemon-backed scripting:

cargo run -p arbor-cli -- health
cargo run -p arbor-cli -- worktrees list --json
cargo run -p arbor-cli -- processes list --json
cargo run -p arbor-cli -- tasks list --json

MCP

Arbor ships a dedicated arbor-mcp binary from the arbor-mcp crate. The stdio server is enabled by the crate's default stdio-server feature and talks to arbor-httpd, so the daemon must be reachable first.

Enable it in a normal build:

cargo build -p arbor-mcp

Environment variables:

• ARBOR_DAEMON_URL overrides the daemon base URL. Default: http://127.0.0.1:8787
• ARBOR_DAEMON_AUTH_TOKEN sends a bearer token for remote authenticated daemons

Remote access:

1. On the daemon host, set [daemon] auth_token = "your-secret" in ~/.config/arbor/config.toml.
2. Start arbor-httpd. When an auth token is configured, Arbor binds remotely by default on 0.0.0.0:8787 unless ARBOR_HTTPD_BIND overrides it.
3. Point arbor-mcp at that daemon with ARBOR_DAEMON_URL=http://HOST:8787.
4. Pass the same secret with ARBOR_DAEMON_AUTH_TOKEN=your-secret.

Loopback requests are allowed without a token. Non-loopback requests require Authorization: Bearer <token>.

Example client config:

{
  "mcpServers": {
    "arbor": {
      "command": "/path/to/arbor-mcp",
      "env": {
        "ARBOR_DAEMON_URL": "http://127.0.0.1:8787"
      }
    }
  }
}

The arbor-mcp binary is feature-gated. To disable the stdio server binary in a build, use:

cargo build -p arbor-mcp --no-default-features

See docs/mcp.md for the full MCP setup guide.

Building from Source

Prerequisites

• Rust nightly — the project uses nightly-2025-11-30 (install via rustup)
• just — task runner
• A Caskaydia / Cascadia Nerd Font variant — icons in the UI use Nerd Font glyphs

macOS

just setup-macos

Or manually:

xcode-select --install
xcodebuild -downloadComponent MetalToolchain
brew install --cask font-caskaydia-cove-nerd-font

Linux (Debian/Ubuntu)

just setup-linux

Or manually:

sudo apt-get install -y libxcb1-dev libxkbcommon-dev libxkbcommon-x11-dev

Then install the CaskaydiaMono Nerd Font to ~/.local/share/fonts/.

Experimental Ghostty VT Engine

Arbor can also be built with an experimental embedded Ghostty terminal engine. This is opt-in, disabled by default, and currently expects:

• the pinned vendor/ghostty submodule checked out
• zig on PATH
• a prebuilt arbor_ghostty_vt_bridge shared library in target/ghostty-vt-bridge/lib
• optionally, ARBOR_GHOSTTY_SRC=/path/to/ghostty to override the pinned submodule
• optionally, ARBOR_GHOSTTY_TARGET / ARBOR_GHOSTTY_CPU to force a safer Zig target in CI

With a build that includes --features ghostty-vt-experimental, Arbor defaults to the embedded Ghostty engine. You can still choose the embedded engine in ~/.config/arbor/config.toml:

embedded_terminal_engine = "ghostty-vt-experimental"

Example:

git submodule update --init --recursive vendor/ghostty
just ghostty-vt-bridge
RUSTFLAGS="-L native=$(pwd)/target/ghostty-vt-bridge/lib -C link-arg=-Wl,-rpath,$(pwd)/target/ghostty-vt-bridge/lib" \
  cargo +nightly-2025-11-30 run -p arbor-gui --features ghostty-vt-experimental

To run Arbor with both embedded engines available and let config.toml choose:

git submodule update --init --recursive vendor/ghostty
just run-configured-embedded-engine

To run the experimental checks:

git submodule update --init --recursive vendor/ghostty
just test-ghostty-vt
just check-ghostty-vt-gui
just check-ghostty-vt-httpd

To compare the embedded engine performance:

git submodule update --init --recursive vendor/ghostty
just bench-embedded-terminal-engines

To build the daemon with the same terminal engine:

git submodule update --init --recursive vendor/ghostty
just ghostty-vt-bridge
RUSTFLAGS="-L native=$(pwd)/target/ghostty-vt-bridge/lib -C link-arg=-Wl,-rpath,$(pwd)/target/ghostty-vt-bridge/lib" \
  cargo +nightly-2025-11-30 run -p arbor-httpd --features ghostty-vt-experimental

Similar Tools

• Superset — terminal-based worktree manager
• Jean — dev environment for AI agents with isolated worktrees and chat sessions
• Conductor — macOS app to orchestrate multiple AI coding agents in parallel worktrees

Acknowledgements

Thanks to Zed for building and open-sourcing GPUI, the GPU-accelerated UI framework that powers Arbor.

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