Cryo MCP Server

Instructions

Implementation Reference

• cryo_mcp/server.py:873-956 (handler)

  The handler function for the 'get_sql_examples' tool, decorated with @mcp.tool() for registration. It returns a hardcoded dictionary containing categorized example SQL queries for querying blockchain data with DuckDB.
  def get_sql_examples() -> Dict[str, List[str]]: """ Get example SQL queries for different blockchain datasets with DuckDB SQL WORKFLOW TIPS: 1. First download data: result = query_dataset('dataset_name', blocks='...', output_format='parquet') 2. Inspect schema: schema = get_sql_table_schema(result['files'][0]) 3. Run SQL: query_sql("SELECT * FROM read_parquet('/path/to/file.parquet')", files=result['files']) OR use the combined approach: - query_blockchain_sql(sql_query="SELECT * FROM read_parquet('...')", dataset='blocks', blocks='...') Returns: Dictionary of example queries categorized by dataset type and workflow patterns """ return { "basic_usage": [ "-- Option 1: Simple table names (recommended)", "SELECT * FROM blocks LIMIT 10", "SELECT * FROM transactions LIMIT 10", "SELECT * FROM logs LIMIT 10", "-- Option 2: Using read_parquet() with explicit file paths", "SELECT * FROM read_parquet('/path/to/blocks.parquet') LIMIT 10" ], "transactions": [ "-- Option 1: Simple table reference", "SELECT * FROM transactions LIMIT 10", "SELECT block_number, COUNT(*) as tx_count FROM transactions GROUP BY block_number ORDER BY tx_count DESC LIMIT 10", "-- Option 2: Using read_parquet()", "SELECT from_address, COUNT(*) as sent_count FROM read_parquet('/path/to/transactions.parquet') GROUP BY from_address ORDER BY sent_count DESC LIMIT 10", "SELECT to_address, SUM(value) as total_eth FROM read_parquet('/path/to/transactions.parquet') GROUP BY to_address ORDER BY total_eth DESC LIMIT 10" ], "blocks": [ "SELECT * FROM blocks LIMIT 10", "SELECT block_number, gas_used, transaction_count FROM blocks ORDER BY gas_used DESC LIMIT 10", "SELECT AVG(gas_used) as avg_gas, AVG(transaction_count) as avg_txs FROM blocks" ], "balances": [ "-- IMPORTANT: When querying the balances dataset, use the 'contract' parameter to specify the address", "-- First download the data:", "# result = query_dataset('balances', blocks='15M:15.01M', contract='0x1234...', output_format='parquet')", "-- Then query the data:", "SELECT block_number, address, balance_f64 FROM balances ORDER BY block_number", "SELECT block_number, balance_f64, balance_f64/1e18 as balance_eth FROM balances ORDER BY block_number" ], "logs": [ "SELECT * FROM logs LIMIT 10", "SELECT address, COUNT(*) as event_count FROM logs GROUP BY address ORDER BY event_count DESC LIMIT 10", "SELECT topic0, COUNT(*) as event_count FROM logs GROUP BY topic0 ORDER BY event_count DESC LIMIT 10" ], "joins": [ "-- Join with simple table references", "SELECT t.block_number, COUNT(*) as tx_count, b.gas_used FROM transactions t JOIN blocks b ON t.block_number = b.block_number GROUP BY t.block_number, b.gas_used ORDER BY tx_count DESC LIMIT 10", "-- Join with read_parquet (useful for complex joins)", "SELECT l.block_number, l.address, COUNT(*) as log_count FROM read_parquet('/path/to/logs.parquet') l GROUP BY l.block_number, l.address ORDER BY log_count DESC LIMIT 10" ], "workflow_examples": [ "-- Step 1: Download data with query_dataset", "# result = query_dataset(dataset='blocks', blocks='15000000:15000100', output_format='parquet')", "-- Step 2: Get schema info", "# schema = get_sql_table_schema(result['files'][0])", "-- Step 3: Run SQL query (simple table reference)", "# query_sql(query=\"SELECT * FROM blocks LIMIT 10\", files=result.get('files', []))", "", "-- Or use the combined function", "# query_blockchain_sql(sql_query=\"SELECT * FROM blocks LIMIT 10\", dataset='blocks', blocks='15000000:15000100')" ], "using_dataset_parameters": [ "-- IMPORTANT: How to check required parameters for datasets", "-- Step 1: Look up the dataset to see required parameters", "# dataset_info = lookup_dataset('balances')", "# This will show: 'required parameters: address'", "", "-- Step 2: Use the contract parameter for ANY address parameter", "# For balances dataset, query_dataset('balances', blocks='1M:1.1M', contract='0x1234...')", "# For erc20_transfers, query_dataset('erc20_transfers', blocks='1M:1.1M', contract='0x1234...')", "", "-- Step 3: Always check the dataset description and schema before querying new datasets", "# This helps ensure you're passing the correct parameters" ] }