Galactic Bridge MCP

An MCP server that lets AI agents and MCP clients (Claude Desktop, Cursor, …) use Galactic Bridge to find LayerZero OFT bridge routes by token contract address and build ready-to-sign cross-chain transactions across 14 EVM networks — including tokens that aren't listed on aggregators like Stargate.

By default this server is read-only. It finds routes and builds transactions, but it never holds a key and never signs anything — a human or wallet does that. Auto-signing is an optional add-on you turn on yourself (see the bottom).

What it does

It talks only to the public Galactic Bridge API — the same endpoints the website calls. It does not run on the bridge's servers and changes nothing there.

Tools

Tool	What it does
`list_supported_networks`	The 14 networks, with chain key, chainId, LayerZero eid and native symbol.
`scan_token_networks`	Given a token address, every network it exists on and its OFT contract on each.
`find_bridge_route`	Resolves a route between two networks: OFT contract, whether the direction is enabled right now, the fee, and — with `amount` + `recipient` — a ready-to-sign transaction (plus an ERC-20 approval when the token bridges through a separate adapter).

find_bridge_route never signs or sends. It returns transaction objects ({ to, data, value, chainId }) for you to review and sign in your own wallet.

Install

Requires Node.js 18+.

Claude Desktop

Add to your claude_desktop_config.json:

json

{
  "mcpServers": {
    "galactic-bridge": {
      "command": "npx",
      "args": ["-y", "galactic-bridge-mcp"]
    }
  }
}

Cursor / other MCP clients

Point the client at the command npx -y galactic-bridge-mcp (stdio transport).

From source

bash

git clone https://github.com/mckellen-eth/galactic-bridge-mcp.git
cd galactic-bridge-mcp
npm install
npm run build
node dist/index.js

Example

"Bridge 50 of token 0x90e7…d9e1 from BNB Chain to Arc, to my address 0xABC…"

The agent calls find_bridge_route and gets back a ready transaction plus the fee. You review it and sign in your wallet. If the token uses a separate adapter, you'll also get an approval transaction to sign first.

Safety

No keys by default. The read-only tools never see a private key.
You sign. Transactions are returned for review; your wallet signs them.
Fees and decimals are read live, so amounts are exact. Directions that a token has disabled are reported instead of returning a transaction that would revert.

Always verify a transaction before signing. This software is provided as-is, with no warranty (MIT).

Optional: auto-signing (advanced)

You can let the server sign and broadcast transactions itself by setting a private key in your environment. This moves real funds irreversibly and is off by default. Only enable it if you understand the risk, and use a dedicated hot wallet that holds no more than you can afford to lose.

json

{
  "mcpServers": {
    "galactic-bridge": {
      "command": "npx",
      "args": ["-y", "galactic-bridge-mcp"],
      "env": {
        "GB_PRIVATE_KEY": "0xyourHotWalletKey"
      }
    }
  }
}

When GB_PRIVATE_KEY is set, an extra tool appears — execute_bridge — which builds, signs and broadcasts the bridge transaction (and the approval first, if needed). It needs the optional ethers package (npm install ethers) and, for networks without a built-in public RPC, an override like GB_RPC_BSC=….

Without GB_PRIVATE_KEY, none of this loads and the server stays read-only.

Configuration

Variable	Purpose
`GB_API_URL`	Override the bridge API base URL (default `https://galacticbridge.app`).
`GB_PRIVATE_KEY`	Opt in to auto-signing. Unset = read-only.
`GB_RPC_<CHAIN>`	RPC URL used by auto-signing for that chain (e.g. `GB_RPC_ARC`).