# 🦞 OpenClaw — Architecture & How It Works

> **Full-Featured Personal AI Assistant** — Massive TypeScript codebase with 15+ channels, companion apps, and enterprise-grade features.

## Overview

OpenClaw is the most feature-complete personal AI assistant in this space. It's a TypeScript monorepo with a WebSocket-based Gateway as the control plane, supporting 15+ messaging channels, companion macOS/iOS/Android apps, browser control, live canvas, voice wake, and extensive automation.

| Attribute | Value |
|-----------|-------|
| **Language** | TypeScript (Node.js ≥22) |
| **Codebase Size** | 430k+ lines, 50+ source modules |
| **Config** | `~/.openclaw/openclaw.json` (JSON5) |
| **AI Runtime** | Pi Agent (custom RPC), multi-model |
| **Channels** | 15+ (WhatsApp, Telegram, Slack, Discord, Signal, iMessage, Teams, Matrix, Zalo, WebChat, etc.) |
| **Package Mgr** | pnpm (monorepo) |

---

## Architecture Flowchart

```mermaid
graph TB
    subgraph Channels["📱 Messaging Channels (15+)"]
        WA["WhatsApp\n(Baileys)"]
        TG["Telegram\n(grammY)"]
        SL["Slack\n(Bolt)"]
        DC["Discord\n(discord.js)"]
        GC["Google Chat"]
        SIG["Signal\n(signal-cli)"]
        BB["BlueBubbles\n(iMessage)"]
        IM["iMessage\n(legacy)"]
        MST["MS Teams"]
        MTX["Matrix"]
        ZL["Zalo"]
        WC["WebChat"]
    end

    subgraph Gateway["🌐 Gateway (Control Plane)"]
        WS["WebSocket Server\nws://127.0.0.1:18789"]
        SES["Session Manager"]
        RTE["Channel Router"]
        PRES["Presence System"]
        Q["Message Queue"]
        CFG["Config Manager"]
        AUTH["Auth / Pairing"]
    end

    subgraph Agent["🧠 Pi Agent (RPC)"]
        AGENT["Agent Runtime"]
        TOOLS["Tool Registry"]
        STREAM["Block Streaming"]
        PROV["Provider Router\n(multi-model)"]
    end

    subgraph Apps["📲 Companion Apps"]
        MAC["macOS Menu Bar"]
        IOS["iOS Node"]
        ANDR["Android Node"]
    end

    subgraph ToolSet["🔧 Tools & Automation"]
        BROWSER["Browser Control\n(CDP/Chromium)"]
        CANVAS["Live Canvas\n(A2UI)"]
        CRON["Cron Jobs"]
        WEBHOOK["Webhooks"]
        GMAIL["Gmail Pub/Sub"]
        NODES["Nodes\n(camera, screen, location)"]
        SKILLS_T["Skills Platform"]
        SESS_T["Session Tools\n(agent-to-agent)"]
    end

    subgraph Workspace["💾 Workspace"]
        AGENTS_MD["AGENTS.md"]
        SOUL_MD["SOUL.md"]
        USER_MD["USER.md"]
        TOOLS_MD["TOOLS.md"]
        SKILLS_W["Skills/"]
    end

    Channels --> Gateway
    Apps --> Gateway
    Gateway --> Agent
    Agent --> ToolSet
    Agent --> Workspace
    Agent --> PROV
```

---

## Message Flow

```mermaid
sequenceDiagram
    participant User
    participant Channel as Channel (WA/TG/Slack/etc.)
    participant GW as Gateway (WS)
    participant Session as Session Manager
    participant Agent as Pi Agent (RPC)
    participant LLM as LLM Provider
    participant Tools as Tools

    User->>Channel: Send message
    Channel->>GW: Forward via channel adapter
    GW->>Session: Route to session (main/group)
    GW->>GW: Check auth (pairing/allowlist)
    Session->>Agent: Invoke agent (RPC)
    Agent->>Agent: Build prompt (AGENTS.md, SOUL.md, tools)
    Agent->>LLM: Stream request (with tool definitions)
    
    loop Tool Use Loop
        LLM-->>Agent: Tool call (block stream)
        Agent->>Tools: Execute tool
        Tools-->>Agent: Tool result
        Agent->>LLM: Continue with result
    end
    
    LLM-->>Agent: Final response (block stream)
    Agent-->>Session: Return response
    Session->>GW: Add to outbound queue
    GW->>GW: Chunk if needed (per-channel limits)
    GW->>Channel: Send chunked replies
    Channel->>User: Display response

    Note over GW: Typing indicators, presence updates
```

---

## Key Components

### 1. Gateway (`src/gateway/`)
The central control plane — everything connects through it:
- **WebSocket server** on `ws://127.0.0.1:18789`
- Session management (main, group, per-channel)
- Multi-agent routing (different agents for different channels)
- Presence tracking and typing indicators
- Config management and hot-reload
- Health checks, doctor diagnostics

### 2. Pi Agent (`src/agents/`)
Custom RPC-based agent runtime:
- Tool streaming and block streaming
- Multi-model support with failover
- Session pruning for long conversations
- Usage tracking (tokens, cost)
- Thinking level control (off → xhigh)

### 3. Channel System (`src/channels/` + per-channel dirs)
15+ channel adapters, each with:
- Auth handling (pairing codes, allowlists, OAuth)
- Message format conversion
- Media pipeline (images, audio, video)
- Group routing with mention gating
- Per-channel chunking (character limits differ)

### 4. Security System (`src/security/`)
Multi-layered security:
- **DM Pairing** — unknown senders get a pairing code, must be approved
- **Allowlists** — per-channel user whitelists
- **Docker Sandbox** — non-main sessions can run in per-session Docker containers
- **Tool denylist** — block dangerous tools in sandbox mode
- **Elevated bash** — per-session toggle for host-level access

### 5. Browser Control (`src/browser/`)
- Dedicated OpenClaw-managed Chrome/Chromium instance
- CDP (Chrome DevTools Protocol) control
- Snapshots, actions, uploads, profiles
- Full web automation capabilities

### 6. Canvas & A2UI (`src/canvas-host/`)
- Agent-driven visual workspace
- A2UI (Agent-to-UI) — push HTML/JS to canvas
- Canvas eval, snapshot, reset
- Available on macOS, iOS, Android

### 7. Voice System
- **Voice Wake** — always-on speech detection
- **Talk Mode** — continuous conversation overlay
- ElevenLabs TTS integration
- Available on macOS, iOS, Android

### 8. Companion Apps
- **macOS app**: Menu bar, Voice Wake/PTT, WebChat, debug tools
- **iOS node**: Canvas, Voice Wake, Talk Mode, camera, Bonjour pairing
- **Android node**: Canvas, Talk Mode, camera, screen recording, SMS

### 9. Session Tools (Agent-to-Agent)
- `sessions_list` — discover active sessions
- `sessions_history` — fetch transcript logs
- `sessions_send` — message another session with reply-back

### 10. Skills Platform (`src/plugins/`, `skills/`)
- **Bundled skills** — pre-installed capabilities
- **Managed skills** — installed from ClawHub registry
- **Workspace skills** — user-created in workspace
- Install gating and UI
- ClawHub registry for community skills

### 11. Automation
- **Cron jobs** — scheduled recurring tasks
- **Webhooks** — external trigger surface
- **Gmail Pub/Sub** — email-triggered actions

### 12. Ops & Deployment
- Docker support with compose
- Tailscale Serve/Funnel for remote access
- SSH tunnels with token/password auth
- `openclaw doctor` for diagnostics
- Nix mode for declarative config

---

## Project Structure (Simplified)

```
openclaw/
├── src/
│   ├── agents/          # Pi agent runtime
│   ├── gateway/         # WebSocket gateway
│   ├── channels/        # Channel adapter base
│   ├── whatsapp/        # WhatsApp adapter
│   ├── telegram/        # Telegram adapter
│   ├── slack/           # Slack adapter
│   ├── discord/         # Discord adapter
│   ├── signal/          # Signal adapter
│   ├── imessage/        # iMessage adapters
│   ├── browser/         # Browser control (CDP)
│   ├── canvas-host/     # Canvas & A2UI
│   ├── sessions/        # Session management
│   ├── routing/         # Message routing
│   ├── security/        # Auth, pairing, sandbox
│   ├── cron/            # Scheduled jobs
│   ├── memory/          # Memory system
│   ├── providers/       # LLM providers
│   ├── plugins/         # Plugin/skill system
│   ├── media/           # Media pipeline
│   ├── tts/             # Text-to-speech
│   ├── web/             # Control UI + WebChat
│   ├── wizard/          # Onboarding wizard
│   └── cli/             # CLI commands
├── apps/                # Companion app sources
├── packages/            # Shared packages
├── extensions/          # Extension channels
├── skills/              # Bundled skills
├── ui/                  # Web UI source
└── Swabble/             # macOS/iOS Swift source
```

---

## CLI Commands

| Command | Description |
|---------|-------------|
| `openclaw onboard` | Guided setup wizard |
| `openclaw gateway` | Start the gateway |
| `openclaw agent --message "..."` | Chat with agent |
| `openclaw message send` | Send to any channel |
| `openclaw doctor` | Diagnostics & migration |
| `openclaw pairing approve` | Approve DM pairing |
| `openclaw update` | Update to latest version |
| `openclaw channels login` | Link WhatsApp |

---

## Chat Commands (In-Channel)

| Command | Description |
|---------|-------------|
| `/status` | Session status (model, tokens, cost) |
| `/new` / `/reset` | Reset session |
| `/compact` | Compact session context |
| `/think <level>` | Set thinking level |
| `/verbose on\|off` | Toggle verbose mode |
| `/usage off\|tokens\|full` | Usage footer |
| `/restart` | Restart gateway |
| `/activation mention\|always` | Group activation mode |

---

## Key Design Decisions

1. **Gateway as control plane** — Single WebSocket server everything connects to
2. **Multi-agent routing** — Different agents for different channels/groups
3. **Pairing-based security** — Unknown DMs get pairing codes by default
4. **Docker sandboxing** — Non-main sessions can be isolated
5. **Block streaming** — Responses streamed as structured blocks
6. **Extension-based channels** — MS Teams, Matrix, Zalo are extensions
7. **Companion apps** — Native macOS/iOS/Android for device-level features
8. **ClawHub** — Community skill registry