x402 Wallet MCP Server

by nirholasio.github.nirholas/x402-mcpv0.2.2

Self-custodial x402 wallet for AI agents: pay any service in USDC or $THREE from your own key.

228Node.jsstdioofficial registry

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Active2d ago

Install x402 Wallet MCP server

claude mcp add x402-nirholas -e SOLANA_SECRET_KEY='<solana-secret-key>' -- npx -y @three-ws/x402-mcp

{
  "mcpServers": {
    "x402-nirholas": {
      "command": "npx",
      "args": [
        "-y",
        "@three-ws/x402-mcp"
      ],
      "env": {
        "SOLANA_SECRET_KEY": "<solana-secret-key>"
      }
    }
  }
}

Add to ~/.cursor/mcp.json (global) or .cursor/mcp.json (project).

{
  "mcpServers": {
    "x402-nirholas": {
      "command": "npx",
      "args": [
        "-y",
        "@three-ws/x402-mcp"
      ],
      "env": {
        "SOLANA_SECRET_KEY": "<solana-secret-key>"
      }
    }
  }
}

Settings → Developer → Edit Config (claude_desktop_config.json), then restart.

{
  "servers": {
    "x402-nirholas": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "@three-ws/x402-mcp"
      ],
      "env": {
        "SOLANA_SECRET_KEY": "<solana-secret-key>"
      }
    }
  }
}

Add to .vscode/mcp.json in your workspace.

{
  "mcpServers": {
    "x402-nirholas": {
      "command": "npx",
      "args": [
        "-y",
        "@three-ws/x402-mcp"
      ],
      "env": {
        "SOLANA_SECRET_KEY": "<solana-secret-key>"
      }
    }
  }
}

Add to ~/.codeium/windsurf/mcp_config.json.

Configuration

Variable	Required	Secret	Description
SOLANA_SECRET_KEY	—	yes	Base58 (or JSON byte-array) Solana secret key that signs payments and holds the USDC. Not needed for the read tools (find_services, inspect_endpoint, or x402_wallet with an explicit address). Treat like cash.
SOLANA_RPC_URL	—	—	Solana mainnet RPC endpoint. Defaults to the public cluster — bring your own (Helius / Quicknode / Triton) for production traffic.
MAX_PAY_USD	—	—	Max USD a single pay_and_call may spend. Bounds a runaway or injected payment.
REQUIRE_CONFIRM	—	—	When on (default), pay_and_call refuses until re-issued with confirm:true. Set 0/false to disable the gate.
THREE_WS_BASE	—	—	Base URL of the three.ws API that serves /api/bazaar/search for find_services. Override only when self-hosting.

Freshness

Active — last maintenance signal 2d ago. The newest of the signals below sets the band.

Last commit (default branch)
2026-10-08 · 2d ago · GitHub
Latest release
2026-09-30 · 10d ago · GitHub · v1.5.2
Package published
no data · npm/PyPI
Registry entry updated
2026-08-19 · 51d ago · official registry · v0.2.2

FAQ

›How do I install the x402 Wallet MCP server in Claude Code?

Run: claude mcp add x402-nirholas -e SOLANA_SECRET_KEY='<solana-secret-key>' -- npx -y @three-ws/x402-mcp. For Cursor, VS Code, Claude Desktop and Windsurf, use the install tabs above.

›Does x402 Wallet require an API key?

Yes. It expects SOLANA_SECRET_KEY, of which 1 is a secret.

›Can I use x402 Wallet as a remote (hosted) MCP server?

No hosted endpoint is published; it runs locally over stdio.

›Is x402 Wallet in the official MCP registry?

Yes, as io.github.nirholas/x402-mcp.