voidsend-mcp

MCP (Model Context Protocol) server for VoidSend — enabling AI agents to send and receive end-to-end encrypted messages.

Features

• End-to-end encryption (X25519 + ML-KEM-768 + AES-256-GCM)
• Wallet-based bot authentication (EIP-191)
• Persistent encryption keys across restarts
• Background polling for new messages (every 15 seconds)
• Full bot lifecycle: wallet creation, registration, messaging

Quick Start

Install

npm install -g voidsend-mcp

Configure with Claude Desktop

Add to your Claude Desktop MCP config (~/Library/Application Support/Claude/claude_desktop_config.json):

{
  "mcpServers": {
    "voidsend": {
      "command": "voidsend-mcp",
      "env": {
        "VOIDSEND_BOT_PRIVATE_KEY": "0x...",
        "VOIDSEND_BOT_NAME": "mybot",
        "VOIDSEND_SERVER_URL": "https://api.voidsend.xyz"
      }
    }
  }
}

Or use the setup tools (see below) to configure interactively.

Configure with Claude Code

Add to your Claude Code MCP settings:

{
  "mcpServers": {
    "voidsend": {
      "command": "npx",
      "args": ["voidsend-mcp"],
      "env": {
        "VOIDSEND_BOT_PRIVATE_KEY": "0x...",
        "VOIDSEND_BOT_NAME": "mybot",
        "VOIDSEND_SERVER_URL": "https://api.voidsend.xyz"
      }
    }
  }
}

Tools

Setup

Tool	Description
create_wallet	Generate a new Ethereum wallet (address + private key)
setup_bot	Register a bot with VoidSend and save credentials
get_setup_status	Check if the bot is configured and authenticated

Messaging

Tool	Description
send_message	Send an E2E encrypted message to a user
read_messages	Read and decrypt recent inbox messages
check_new_messages	Get new messages since last check (from polling)
list_contacts	List users who have messaged the bot
get_bot_info	Show bot account info (synonym, wallet, server)

Environment Variables

Variable	Required	Description
VOIDSEND_BOT_PRIVATE_KEY	Yes*	Ethereum private key (hex)
VOIDSEND_BOT_NAME	Yes*	Bot name (auto-prefixed with bot.)
VOIDSEND_SERVER_URL	No	Server URL (default: https://api.voidsend.xyz)

* Can be set via the setup_bot tool instead.

How It Works

1. First run: Use create_wallet to generate a wallet, then setup_bot to register
2. Authentication: Bot signs a challenge with its private key (EIP-191)
3. Encryption: Messages are encrypted client-side with hybrid post-quantum cryptography
4. Polling: Background polling every 15s detects new messages automatically
5. Keys: Encryption keys persist at ~/.voidsend/bot.<name>.keys.json

Bot Restrictions

• Bots can only reply to users who have messaged them first
• Bots cannot initiate audio/video calls
• Users can block bots like any other user

License

MIT