Vultisig MCP Server

An MCP server that exposes Vultisig vault operations and Ethereum balance queries to LLM-powered agents. Supports both stdio and HTTP transports.

Quick Start

# Build
go build -o mcp-server ./cmd/mcp-server/

# Run over stdio (default)
./mcp-server

# Run over HTTP on port 8080
./mcp-server -http :8080

# With a custom RPC endpoint
ETH_RPC_URL=https://your-rpc.example.com ./mcp-server -http :8080

Tools

set_vault_info

Store vault key material for the current session. Must be called before vault-derived balance queries.

Parameter	Required	Description
ecdsa_public_key	Yes	Hex-encoded compressed ECDSA public key (66 hex chars)
eddsa_public_key	Yes	Hex-encoded EdDSA public key (64 hex chars)
chain_code	Yes	Hex-encoded 32-byte chain code for BIP-32 derivation

get_address

Derive the address for a given blockchain network from the vault's key material. Requires set_vault_info first.

Parameter	Required	Description
chain	Yes	Blockchain network name (see supported chains below)

Supported chains: Arbitrum, Avalanche, Base, Bitcoin, Bitcoin-Cash, Blast, BSC, Cosmos, CronosChain, Dash, Dogecoin, Dydx, Ethereum, Kujira, Litecoin, Mantle, MayaChain, Noble, Optimism, Osmosis, Polygon, Ripple, Solana, Sui, Terra, TerraClassic, THORChain, Tron, Zcash, Zksync.

get_eth_balance

Query the native ETH balance. Derives the address from vault keys if not provided.

Parameter	Required	Description
address	No	Ethereum address (0x-prefixed). Falls back to vault-derived address.

get_token_balance

Query an ERC-20 token balance. Derives the holder address from vault keys if not provided.

Parameter	Required	Description
contract_address	Yes	ERC-20 token contract address (0x-prefixed)
address	No	Holder address (0x-prefixed). Falls back to vault-derived address.

MCP Client Configuration

Stdio (default)

{
  "mcpServers": {
    "vultisig": {
      "command": "/path/to/mcp-server",
      "env": {
        "ETH_RPC_URL": "https://ethereum-rpc.publicnode.com"
      }
    }
  }
}

HTTP

# Start the server
./mcp-server -http :8080

# MCP endpoint: POST/GET/DELETE http://localhost:8080/mcp

{
  "mcpServers": {
    "vultisig": {
      "url": "http://localhost:8080/mcp"
    }
  }
}