Bedrock AFK Bot

A Discord bot that manages persistent AFK (Away From Keyboard) sessions for Minecraft Bedrock Edition servers. The bot maintains 24/7 connections to Minecraft servers with automatic reconnection, anti-AFK mechanics, and Microsoft account integration.

How It Works

The bot creates lightweight Minecraft Bedrock clients through Discord commands. Each user can run one bot instance that connects to a specified server, performs anti-AFK actions (arm swinging, crouching), and automatically reconnects if disconnected.

Core Architecture

Session Management

• Each Discord user gets one persistent Minecraft session
• Sessions survive bot restarts through JSON-based storage (rejoin.json)
• Write-ahead logging (WAL) ensures data integrity during crashes
• Graceful shutdown with 15-second timeout for cleanup

Connection Lifecycle

1. User configures server IP/port via Settings modal
2. Bot verifies Microsoft authentication (device code flow via prismarine-auth)
3. Creates bedrock-protocol client with 30-second connection timeout
4. Monitors health via keepalive packets (15s interval) and stale connection detection (60s timeout)
5. On disconnect: exponential backoff reconnection (5s base, max 5min jitter)
6. Native cleanup delays (2s) prevent heap corruption from rapid reconnects

Anti-AFK System

• Randomized actions every 8-20 seconds:
  • 60% chance: Arm swing animation
  • 20% chance: Crouch toggle (2-4s duration)
  • 20% chance: No action
• Prevents server kick for inactivity while maintaining minimal bandwidth

Authentication Flow

Online Mode (Default)

• Requires Microsoft account linking via /link command
• Uses device code OAuth flow (Nintendo Switch device type)
• Tokens stored locally per-user in data/auth/[uid]/
• 5-minute timeout for authentication completion
• Auto-detects expired tokens (5min buffer before expiry)

Offline Mode

• Optional per-user setting
• Username auto-generated as AFK_[last4digits]
• No Microsoft account required
• Limited to cracked/offline-mode servers

Admin Panel

Admin users (configured via ADMIN_ID) access:

• Real-time RAM/Heap monitoring
• Active session registry with connection status
• Force-stop individual or all sessions
• Manual data persistence triggers
• Auto-refreshing embed (30s interval)

Safety Mechanisms

Crash Prevention

• Native memory corruption protection: 2-second delays between session cleanup and reconnection
• Skips bedrock.ping() on reconnects to avoid double-free heap errors in RakNet native bindings
• All errors caught silently with optional crash logging to data/crash.log
• Operation timeouts (30s) on client creation to prevent hanging promises

Rate Limiting

• 1-second cooldown per user on button interactions
• Discord REST retry logic with 3 attempts

Data Integrity

• Atomic file writes (write to .tmp, rename to target)
• Automatic backup of corrupt JSON files
• Emergency backup on save failures

Installation

Requirements

• Node.js 18+
• Discord Bot Token
• 512MB+ RAM (scales with concurrent sessions)

Setup

1. Clone and install

git clone <repo>
cd bedrock-afk-bot
npm install discord.js bedrock-protocol prismarine-auth