Cryo MCP (with Payflow)

Cryo MCP is an MCP server that allows you to extensively query blockchain data in natural language, powered by Cryo and Reth.

We host a remote MCP server at https://cryo-mcp.fly.dev/v1/mcp that you can use to test it out. It is connected to a Reth archive node and has access to all datasets that Cryo provides:

cryo datasets
─────────────
- address_appearances
- balance_diffs
- balance_reads
- balances
- blocks
- code_diffs
- code_reads
- codes
- contracts
- erc20_balances
- erc20_metadata
- erc20_supplies
- erc20_transfers
- erc721_metadata
- erc721_transfers
- eth_calls
- four_byte_counts (alias = 4byte_counts)
- geth_calls
- geth_code_diffs
- geth_balance_diffs
- geth_storage_diffs
- geth_nonce_diffs
- geth_opcodes
- javascript_traces (alias = js_traces)
- logs (alias = events)
- native_transfers
- nonce_diffs
- nonce_reads
- nonces
- slots (alias = storages)
- storage_diffs (alias = slot_diffs)
- storage_reads (alias = slot_reads)
- traces
- trace_calls
- transactions (alias = txs)
- vm_traces (alias = opcode_traces)

It is also a demonstration of how to use payflow to integrate micropayments into your MCP server. To use it, you need to have a local payflow MCP server running that can create the payments for the paid tools.

Claude Desktop Quickstart

1. Press cmd+, in Claude Desktop to open the settings
2. Go to the Developer tab
3. Click edit config and open the claude_desktop_config.json file
4. Add the cryo server to the mcpServers object:
5. Add the payflow server to the mcpServers object, with the correct configuration:

{
  "mcpServers": {
    "cryo": {
      "command": "npx",
      "args": [
        "mcp-remote",
        "https://cryo-mcp.fly.dev/v1/mcp",
        "--header",
        "Authorization: test",
        "--transport",
        "http-only"
      ]
    },
    "payflow": {
      "command": "npx",
      "args": ["@chainbound/payflow-mcp"],
      "env": {
        "PRIVATE_KEY": "",
        // Set your max payment amount in USDC per tool call
        "MAX_PAYMENT_AMOUNT_USDC": "10",
        // Enable debug logging
        "DEBUG": "payflow:*"
      }
    }
  }
}

Paid Tools

Only the dataset generation (query_dataset) tool is paid, using Coinbase x402 through the payflow-sdk package. It currently costs 0.05 USDC and is payable on Base. The MCP server uses the facilitator hosted by Coinbase to settle the payments.

Limits

We limit the number of blocks per query to 10,000. If your agent needs more data, you can use the query_dataset tool multiple times with multiple payments.

Sequence Diagram

sequenceDiagram
    box Grey Local
    participant Claude
    participant Payflow MCP
    end
    box Purple Remote
    participant Cryo MCP
    participant Facilitator
    end
    Claude->>+Cryo MCP: get_tool_details
    Cryo MCP -->>-Claude: details
    Claude->>Claude: evaluate_details
    alt proceed
        Claude->>+Payflow MCP: generate_payment
        Payflow MCP->>-Claude: payment_details
        Claude->>+Cryo MCP: tool_call, payment
        Cryo MCP->>+Facilitator: verify and settle
        Facilitator->>-Cryo MCP: response (success)
        Cryo MCP->>-Claude: tool_result
        Claude->>Claude: process & present result to user
    end