ClickHouse MCP Server

Implementation Reference

• mcp_clickhouse/mcp_server.py:28-34 (handler)

  The handler function for the 'list_databases' tool. It uses a ClickHouse client to execute the 'SHOW DATABASES' command and returns the list of databases.

  @mcp.tool()
  def list_databases():
      logger.info("Listing all databases")
      client = create_clickhouse_client()
      result = client.command("SHOW DATABASES")
      logger.info(f"Found {len(result) if isinstance(result, list) else 1} databases")
      return result

• mcp_clickhouse/mcp_server.py:104-115 (helper)

  Helper function to create and return a ClickHouse client instance using environment variables, used by the list_databases handler.

  def create_clickhouse_client():
      host = os.getenv("CLICKHOUSE_HOST")
      port = os.getenv("CLICKHOUSE_PORT")
      username = os.getenv("CLICKHOUSE_USER")
      logger.info(f"Creating ClickHouse client connection to {host}:{port} as {username}")
      return clickhouse_connect.get_client(
          host=host,
          port=port,
          username=username,
          password=os.getenv("CLICKHOUSE_PASSWORD"),
      )