Cryo MCP Server

Instructions

Get detailed information about a transaction by its hash

Args:
    tx_hash: The transaction hash to look up
    
Returns:
    Detailed information about the transaction

Implementation Reference

• cryo_mcp/server.py:479-572 (handler)

  The main handler function for the 'get_transaction_by_hash' tool. It uses Ethereum JSON-RPC calls (eth_getTransactionByHash and eth_getTransactionReceipt) to fetch and combine transaction details including block info, gas usage, status, and EIP-1559 fields if applicable.

  @mcp.tool()
  def get_transaction_by_hash(
      tx_hash: str
  ) -> Dict[str, Any]:
      """
      Get detailed information about a transaction by its hash
      
      Args:
          tx_hash: The transaction hash to look up
          
      Returns:
          Detailed information about the transaction
      """
      # Ensure we have the RPC URL
      rpc_url = os.environ.get("ETH_RPC_URL", DEFAULT_RPC_URL)
      
      # Use RPC directly to get the transaction
      payload = {
          "jsonrpc": "2.0",
          "method": "eth_getTransactionByHash",
          "params": [tx_hash],
          "id": 1
      }
      
      try:
          response = requests.post(rpc_url, json=payload)
          response_data = response.json()
          
          if 'result' in response_data and response_data['result']:
              tx_data = response_data['result']
              
              # Get the receipt as well for additional information (gas used, status)
              receipt_payload = {
                  "jsonrpc": "2.0",
                  "method": "eth_getTransactionReceipt",
                  "params": [tx_hash],
                  "id": 2
              }
              
              receipt_response = requests.post(rpc_url, json=receipt_payload)
              receipt_data = receipt_response.json()
              
              if 'result' in receipt_data and receipt_data['result']:
                  receipt = receipt_data['result']
                  
                  # Combine transaction and receipt data
                  result = {
                      "transaction_hash": tx_hash,
                      "block_number": int(tx_data.get("blockNumber", "0x0"), 16),
                      "block_hash": tx_data.get("blockHash"),
                      "from_address": tx_data.get("from"),
                      "to_address": tx_data.get("to"),
                      "value": tx_data.get("value"),
                      "value_decimal": int(tx_data.get("value", "0x0"), 16),
                      "gas_limit": int(tx_data.get("gas", "0x0"), 16),
                      "gas_price": int(tx_data.get("gasPrice", "0x0"), 16),
                      "nonce": int(tx_data.get("nonce", "0x0"), 16),
                      "input": tx_data.get("input"),
                      "transaction_index": int(tx_data.get("transactionIndex", "0x0"), 16),
                      "gas_used": int(receipt.get("gasUsed", "0x0"), 16),
                      "status": int(receipt.get("status", "0x0"), 16),
                      "logs_count": len(receipt.get("logs", [])),
                      "contract_address": receipt.get("contractAddress")
                  }
                  
                  # Handle EIP-1559 transactions
                  if "maxFeePerGas" in tx_data:
                      result["max_fee_per_gas"] = int(tx_data.get("maxFeePerGas", "0x0"), 16)
                      result["max_priority_fee_per_gas"] = int(tx_data.get("maxPriorityFeePerGas", "0x0"), 16)
                      result["transaction_type"] = int(tx_data.get("type", "0x0"), 16)
                  
                  return result
              else:
                  # Return just the transaction data if receipt is not available
                  return {
                      "transaction_hash": tx_hash,
                      "block_number": int(tx_data.get("blockNumber", "0x0"), 16),
                      "block_hash": tx_data.get("blockHash"),
                      "from_address": tx_data.get("from"),
                      "to_address": tx_data.get("to"),
                      "value": tx_data.get("value"),
                      "value_decimal": int(tx_data.get("value", "0x0"), 16),
                      "gas_limit": int(tx_data.get("gas", "0x0"), 16),
                      "gas_price": int(tx_data.get("gasPrice", "0x0"), 16),
                      "nonce": int(tx_data.get("nonce", "0x0"), 16),
                      "input": tx_data.get("input"),
                      "transaction_index": int(tx_data.get("transactionIndex", "0x0"), 16),
                      "error": "Failed to retrieve transaction receipt"
                  }
          else:
              return {"error": f"Transaction not found: {tx_hash}"}
      except Exception as e:
          return {"error": f"Exception when fetching transaction: {e}"}