ChainProbe – Onchain Chainlink Price Feeds for M2M Processing with MCP

ChainProbe is an x402-capable MCP server that delivers onchain Chainlink price feeds across multiple EVM blockchains in a single unified interface. Built on the Model Context Protocol (MCP), it enables composable integration of blockchain data into AI, agentic systems, and Machine-to-Machine (M2M) workflows.

By implementing MCP’s resources and tools features, ChainProbe exposes real-time price data streams that can be consumed via HTTP 402-based micropayments using USDC. No API keys. No offchain databases. Just streaming blockchain-native data, made machine-readable.

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🔗 Live Endpoint

x402 proxy access for compatible clients:

➡️ https://community.flowmcp.org/chainlink/prices

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📡 What Does ChainProbe Do?

ChainProbe aggregates all Chainlink price feeds of a blockchain into a single endpoint. Access is restricted to valid X-PAYMENT headers, using exact scheme payments (EIP-3009) via USDC.

🌍 Supported Blockchains

Blockchain	Number of Feeds
Ethereum Mainnet	140
Binance Mainnet	125
Polygon Mainnet	127
Avalanche Mainnet	58
Arbitrum Mainnet	127
Optimism Mainnet	113
Base Mainnet	54
Starknet Mainnet	9
Linea Mainnet	15
Mantle Mainnet	6
Scroll Mainnet	22
zkSync Mainnet	16
Celo Mainnet	22

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⚙️ Route Details

• Path: /chainlink/prices
• Protocol: Server-Sent Events (text/event-stream)
• Payment: USDC on Base Sepolia
• x402 Scheme: exact (EIP-3009)
• Token: hal-finney (public)
• Namespaces: x402, chainlink

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🧠 Why x402?

x402 replaces traditional API keys and subscriptions with machine-native payments via HTTP 402. It's purpose-built for autonomous systems and agents:

• No API key management
• Pay-per-request
• Fully onchain verifiable
• Ideal for AI and M2M workflows

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🧪 Usage via Proxy (Example)

✅ Connects Claude Mac to 👉 https://community.flowmcp.org/chainlink/prices/sse — a public payment-enforced remote server ✅ Manages payments automatically via proxy using the X-PAYMENT header

Claude Mac Configuration Snippet

{
  "globalShortcut": "",
  "mcpServers": {
    "chainlink-proxy": {
      "command": "node",
      "args": [
        "your/absolute/path/proxyserver.mjs"
      ],
      "env": {
        "SILENT": "true"
      }
    }
  }
}

Make sure to create a .env file beforehand. See .example.env for guidance.

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🛠 Tech Stack

• Express.js with x402 middleware
• Server-Sent Events output
• Onchain Chainlink Aggregators
• Payments using exact scheme (EIP-3009)
• Running on Base Sepolia Testnet

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🧩 Modules Built for the Hackathon

Several modules were created from scratch or extended to support full x402 integration:

Module	Description
x402-core	🔧 Built from scratch: full client/server logic for EIP-3009 token payments
x402-mcp-middleware	🔧 Built from scratch: enforces x402 payments in Express-based AI tools
FlowMCP	♻️ Extended: tool orchestration & schema-based agent framework
community-server	♻️ Extended: live integration server hosting all modules

🔗 All modules are live at: https://community.flowmcp.org/chainlink/prices/sse

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🔮 Next Steps

• Pricing via EIP-2612
• Multi-chain support
• Symbol-based feed filtering
• Statistical aggregation (24h, 7d, etc.)

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📚 Resources

• x402 Whitepaper
• Chainlink Documentation
• x402 Experiments GitHub