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MCP SERVER

Agent wallet tools for any MCP client.

The official Blockchain0x MCP server gives an MCP-aware agent the power to read wallets, send USDC on Base, and settle invoices. Connect the hosted endpoint, or run it locally with one command.

https://mcp.blockchain0x.com/mcp
WHAT IT IS

One server. Five tools. Every MCP client.

The Model Context Protocol is the standard way AI clients - Claude Desktop, Cursor, Cline, and others - call external tools. The Blockchain0x MCP server exposes your agent wallets through that standard, so any MCP client can move money without you writing a custom integration.

The server is a thin, stateless proxy over the Blockchain0x API. It holds no funds and no database; it forwards each tool call to the API using the key you supply, and the spend permission on each agent still bounds what a tool can do.

THE TOOLS

What the agent can call.

get_wallet

Read one agent's wallet: address, USDC balance on Base, and metadata.

list_wallets

List the agent wallets in your workspace.

get_transaction

Look up a transaction by its id and read its on-chain status.

send_payment

Send USDC from an agent's wallet on Base, within its spend permission.

settle_payment_request

Settle a payment request you created in the dashboard, with on-chain proof.

HOW TO USE IT

Two ways to connect.

1. Hosted (Streamable HTTP)

Point your MCP client at the hosted endpoint and pass your API key as a Bearer header. Nothing to install.

MCP CLIENT CONFIG (HOSTED)
{
  "mcpServers": {
    "blockchain0x": {
      "url": "https://mcp.blockchain0x.com/mcp",
      "headers": { "Authorization": "Bearer sk_live_..." }
    }
  }
}

2. Local (stdio, via npx)

Run the server on your own machine with npx @blockchain0x/mcp. Your key stays in your environment and never leaves your device.

MCP CLIENT CONFIG (STDIO)
{
  "mcpServers": {
    "blockchain0x": {
      "command": "npx",
      "args": ["@blockchain0x/mcp"],
      "env": { "BLOCKCHAIN0X_API_KEY": "sk_live_..." }
    }
  }
}

Start on an sk_test_ key against Base Sepolia, then switch to sk_live_. Full setup is in the docs; to put a price on your own MCP tools, see the MCP integration recipe.

SECURITY

The spend permission still applies.

  • The server never holds your funds or your keys; it forwards each call to the Blockchain0x API.
  • send_payment is checked against the agent's per-transaction cap and per-period allowance before it settles, the same as any other API call.
  • Use a read-only key (no pay scope) for an agent that should only read wallets and transactions.
  • On stdio, the key stays in your local environment. On hosted, it travels as a Bearer header over TLS and is not stored.
FREQUENTLY ASKED

Three MCP server questions.

Where does the MCP server run, and do you see my key?

Two ways to run it. Hosted: connect your MCP client to the Streamable HTTP endpoint and send your API key as a Bearer header on each request; the server is a stateless proxy that forwards calls to the Blockchain0x API. Local (stdio): run npx @blockchain0x/mcp on your own machine and your key stays in your environment, never leaving your device. Pick stdio if you would rather not send the key to a hosted endpoint.

Which API key should I use?

An sk_test_ key runs against Base Sepolia (testnet) so you can wire up the tools without moving real money; switch to an sk_live_ key for mainnet. The key's scopes decide what the tools can do - a read-only key can call get_wallet, list_wallets, and get_transaction but not send_payment.

Is this the same as the requirePayment helper?

No. This page is about the Blockchain0x MCP server, which gives an MCP client agent wallet tools (read wallets, send USDC, settle invoices). requirePayment is a separate helper in @blockchain0x/mcp that you use to put a price on your OWN MCP tools by returning an x402 402 challenge. See the MCP integration recipe for that.

Give your MCP client a wallet.

Create an agent wallet, grab a key, and point your client at the server. Free to start.