CrossFin MCP Server

Give your AI agent access to Asian crypto markets. 16 tools for real-time Korean exchange data, cross-exchange routing, and x402 paid API execution across 14 exchanges.

Quick Start

npx -y crossfin-mcp

That's it. Your agent now has 16 tools. Most tools work with no wallet setup, and payment-capable tools require EVM_PRIVATE_KEY.

Open beta note: CrossFin API endpoints are currently free, but payment-capable MCP tools still require wallet config for x402 flow compatibility.

Client Configuration

Claude Desktop

~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

{
  "mcpServers": {
    "crossfin": {
      "command": "npx",
      "args": ["-y", "crossfin-mcp"],
      "env": {
        "EVM_PRIVATE_KEY": "0x..."
      }
    }
  }
}

Cursor

.cursor/mcp.json in your project root:

{
  "mcpServers": {
    "crossfin": {
      "command": "npx",
      "args": ["-y", "crossfin-mcp"],
      "env": {
        "EVM_PRIVATE_KEY": "0x..."
      }
    }
  }
}

VS Code

.vscode/mcp.json in your project root (or user-level in settings):

{
  "inputs": [
    {
      "type": "promptString",
      "id": "evm-key",
      "description": "Base wallet private key for x402 payments (optional)",
      "password": true
    }
  ],
  "servers": {
    "crossfin": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "crossfin-mcp"],
      "env": {
        "EVM_PRIVATE_KEY": "${input:evm-key}"
      }
    }
  }
}

Windsurf

~/.codeium/windsurf/mcp_config.json:

{
  "mcpServers": {
    "crossfin": {
      "command": "npx",
      "args": ["-y", "crossfin-mcp"],
      "env": {
        "EVM_PRIVATE_KEY": "0x..."
      }
    }
  }
}

npx (standalone)

EVM_PRIVATE_KEY=0x... npx -y crossfin-mcp

No EVM key? Omit EVM_PRIVATE_KEY entirely. Free tools work without one.

All 16 Tools

Routing Engine

| Tool | Price | Description | |------|-------|-------------| | find_optimal_route | x402 flow | Optimal crypto transfer path across 14 exchanges with 13 bridge coins | | list_exchange_fees | Free | Trading + withdrawal fee comparison for all exchanges | | compare_exchange_prices | Free | Live Bithumb KRW vs Binance USD price comparison | | get_kimchi_premium | Free | Korean vs. global route spread preview (top 3 pairs) |

Paid API Gateway

| Tool | Price | Description | |------|-------|-------------| | call_paid_service | x402 flow | Call catalog premium endpoints with automatic x402 USDC payment |

Service Registry

| Tool | Price | Description | |------|-------|-------------| | search_services | Free | Search registered services by keyword | | list_services | Free | Browse the service catalog with category filter | | get_service | Free | Get details for a specific service | | list_categories | Free | List all service categories with counts | | get_guide | Free | Full CrossFin agent guide (services, pricing, x402 flow) | | get_analytics | Free | Gateway usage stats (total calls, top services) |

Local Ledger

| Tool | Price | Description | |------|-------|-------------| | create_wallet | Free | Create a wallet in the local CrossFin ledger | | get_balance | Free | Check wallet balance (KRW) | | transfer | Free | Transfer funds between wallets | | list_transactions | Free | Transaction history (optionally filtered by wallet) | | set_budget | Free | Set a daily spend limit (KRW) |

Sample Prompts

Korean

빗썸에서 바이낸스로 500만원 USDC 만들려면 가장 싼 방법이 뭐야?

지금 한국-글로벌 스프레드 얼마야?

거래소별 XRP 가격 비교해줘

오늘 한국 시장 브리핑해줘

English

What's the cheapest way to move 5M KRW from Bithumb to Binance as USDC?

Show me the current Korea-global crypto spread.

Compare XRP prices across exchanges.

Give me this morning's Korean market brief.

Supported Exchanges

Korea: Bithumb, Upbit, Coinone, GoPax Regional Fiat: bitFlyer, WazirX, bitbank, Indodax, Bitkub Global: Binance, OKX, Bybit, KuCoin, Coinbase

Bridge Coins

BTC, ETH, XRP, SOL, DOGE, ADA, DOT, LINK, AVAX, TRX, KAIA, SUI, APT

Environment Variables

| Variable | Required | Description | |----------|----------|-------------| | EVM_PRIVATE_KEY | For paid tools | Base wallet private key for x402 USDC payments | | CROSSFIN_API_URL | No | API base URL (default: https://crossfin.dev) | | CROSSFIN_LEDGER_PATH | No | Local ledger file path (default: ~/.crossfin/ledger.json) |

x402 Payments

Paid tools use the x402 protocol for automatic micropayments. When your agent calls a paid endpoint:

1. The API responds with 402 Payment Required and a price header
2. The MCP server signs a USDC payment on Base (L2) using your EVM_PRIVATE_KEY
3. The payment is submitted and the API returns the data along with a transaction receipt

Payments settle on-chain. Each response includes txHash and a Basescan link for verification. Prices range from $0.01 to $0.20 per call.

To get started, fund a Base wallet with USDC and set EVM_PRIVATE_KEY. No account registration or API keys required.

Agent Discovery

CrossFin exposes standard discovery endpoints so agent frameworks can auto-detect capabilities:

| Endpoint | Description | |----------|-------------| | /.well-known/ai-plugin.json | OpenAI plugin manifest | | /.well-known/agent.json | A2A Agent Card (Google Agent-to-Agent protocol) | | /.well-known/x402.json | x402 payment discovery (network, token, payTo) | | /.well-known/crossfin.json | CrossFin metadata (MCP, API, registry links) | | /llms.txt | LLM-friendly service description |

Links

• crossfin.dev -- Dashboard & API
• live.crossfin.dev -- Live routing demo
• docs.crossfin.dev -- Documentation
• GitHub -- Source code
• npm -- Package