Voyager MCP Server — Starknet data for AI coding agents

The Voyager MCP server gives AI coding agents direct access to live Starknet data — the same data the Voyager explorer shows. Ask your agent about a transaction, read a contract’s verified Cairo code, inspect token holders, and more, without leaving your editor.

No API key. It talks to the same API the explorer uses.
Local & lightweight. Runs on your machine over stdio via npx — nothing to host.
Mainnet & Sepolia. Switch networks with one env var.

Tools & usage

The full tool catalog and how an agent should chain calls

Explorer

The Voyager block explorer

Prerequisites

Node.js 20.3 or newer (npx ships with it).
An MCP-capable client: Claude Code, Claude Desktop, Cursor, or Codex.

The package is available on npm as voyager-mcp. npx -y voyager-mcp downloads and runs it for you — there is nothing to install or build.

Setup

Claude Code
Claude Desktop
Cursor
Codex

Add the server with one command (run it in your project, or with -s user to make it global):

claude mcp add voyager -- npx -y voyager-mcp

Or commit it to your repo so the whole team gets it — create .mcp.json in the project root:

.mcp.json

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

Open Settings → Developer → Edit Config (this opens claude_desktop_config.json) and add the voyager server:

claude_desktop_config.json

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

Fully quit Claude Desktop (⌘Q / restart) and reopen it.

Add the server to ~/.cursor/mcp.json (global) or .cursor/mcp.json (per project):

.cursor/mcp.json

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

Enable it under Cursor Settings → MCP.

Add the server with one command:

codex mcp add voyager -- npx -y voyager-mcp

Or add it manually to ~/.codex/config.toml:

~/.codex/config.toml

[mcp_servers.voyager]
command = "npx"
args = ["-y", "voyager-mcp"]

Windows: if npx isn’t found, use "command": "npx.cmd" (or wrap with cmd /c npx -y voyager-mcp).

Choose a network

The server defaults to mainnet. To target Sepolia testnet, set VOYAGER_NETWORK:

{
  "mcpServers": {
    "voyager": {
      "command": "npx",
      "args": ["-y", "voyager-mcp"],
      "env": { "VOYAGER_NETWORK": "sepolia" }
    }
  }
}

For Codex, set it in ~/.codex/config.toml instead:

[mcp_servers.voyager]
command = "npx"
args = ["-y", "voyager-mcp"]
env = { "VOYAGER_NETWORK" = "sepolia" }

Try it

Once the server is connected, ask your agent things like:

“Use voyager to get the current Starknet network stats.”
“Look up Starknet transaction 0x… and the events it emitted.”
“Show me the verified Cairo code for class 0x….”
“What’s the class hash and type of contract 0x…?”
“Who are the top holders of token 0x…?”
“Is token 0x… safe? Run a security scan.”

The agent picks the right tools automatically. See Tools & usage for the full catalog and the recipes it follows to chain calls.

Verify the connection

Claude Code: run /mcp — voyager should be listed as connected.
Claude Desktop / Cursor: the tools appear in the tools/MCP menu once the client restarts.
Codex: run codex mcp list — voyager should be listed.

If it doesn’t connect, confirm Node 20.3+ is installed and that npx -y voyager-mcp runs from your terminal (the first run downloads the package, which can take a few seconds).

Tools & usage

Explorer

​Prerequisites

​Setup

​Choose a network

​Try it

​Verify the connection

Prerequisites

Setup

Choose a network

Try it

Verify the connection