crossfin-mcp

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:

• The API responds with 402 Payment Required and a price header
• The MCP server signs a USDC payment on Base (L2) using your EVM_PRIVATE_KEY
• 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