list_tables

Instructions

Implementation Reference

• src/adx_mcp_server/server.py:223-241 (handler)

  The 'list_tables' tool handler function. It is decorated with @mcp.tool, connects to ADX, runs '.show tables | project TableName, Folder, DatabaseName', formats and returns results.

  @mcp.tool(description="Retrieves a list of all tables available in the configured Azure Data Explorer database, including their names, folders, and database associations.")
  async def list_tables() -> List[Dict[str, Any]]:
      """List all tables in the configured ADX database."""
      logger.info("Listing tables", database=config.database)
  
      if not config.cluster_url or not config.database:
          logger.error("Missing ADX configuration")
          raise ValueError("Azure Data Explorer configuration is missing. Please set ADX_CLUSTER_URL and ADX_DATABASE environment variables.")
  
      try:
          client = get_kusto_client()
          query = ".show tables | project TableName, Folder, DatabaseName"
          result_set = client.execute(config.database, query)
          results = format_query_results(result_set)
          logger.info("Tables listed successfully", table_count=len(results))
          return results
      except Exception as e:
          logger.error("Failed to list tables", error=str(e), exception_type=type(e).__name__)
          raise

• src/adx_mcp_server/server.py:223-223 (registration)

  The tool registration using the @mcp.tool decorator from FastMCP, which registers 'list_tables' as an MCP tool with FastMCP.

  @mcp.tool(description="Retrieves a list of all tables available in the configured Azure Data Explorer database, including their names, folders, and database associations.")

• src/adx_mcp_server/server.py:84-137 (helper)

  The get_kusto_client() helper used by list_tables to create a KustoClient with Azure credentials.

  def get_kusto_client() -> KustoClient:
      """
      Create and configure a Kusto client with appropriate Azure credentials.
  
      Prioritizes WorkloadIdentityCredential when running in AKS with workload identity,
      falls back to DefaultAzureCredential for other authentication methods.
  
      Returns:
          KustoClient: Configured Kusto client instance
      """
      tenant_id = os.environ.get('AZURE_TENANT_ID')
      client_id = os.environ.get('AZURE_CLIENT_ID')
      token_file_path = os.environ.get('ADX_TOKEN_FILE_PATH', '/var/run/secrets/azure/tokens/azure-identity-token')
  
      if tenant_id and client_id:
          logger.info(
              "Using WorkloadIdentityCredential",
              client_id=client_id,
              tenant_id=tenant_id,
              token_file_path=token_file_path
          )
          try:
              credential = WorkloadIdentityCredential(
                  tenant_id=tenant_id,
                  client_id=client_id,
                  token_file_path=token_file_path
              )
          except Exception as e:
              logger.warning(
                  "Failed to initialize WorkloadIdentityCredential, falling back",
                  error=str(e),
                  exception_type=type(e).__name__
              )
              credential = DefaultAzureCredential()
      else:
          logger.info("Using DefaultAzureCredential (missing WorkloadIdentity credentials)")
          credential = DefaultAzureCredential()
  
      try:
          kcsb = KustoConnectionStringBuilder.with_azure_token_credential(
              connection_string=config.cluster_url,
              credential=credential
          )
          client = KustoClient(kcsb)
          logger.debug("Kusto client initialized successfully", cluster_url=config.cluster_url)
          return client
      except Exception as e:
          logger.error(
              "Failed to create Kusto client",
              error=str(e),
              exception_type=type(e).__name__,
              cluster_url=config.cluster_url
          )
          raise

• src/adx_mcp_server/server.py:139-172 (helper)

  The format_query_results() helper used by list_tables to format Kusto query results into dictionaries.

  def format_query_results(result_set) -> List[Dict[str, Any]]:
      """
      Format Kusto query results into a list of dictionaries.
  
      Args:
          result_set: Raw result set from KustoClient
  
      Returns:
          List of dictionaries with column names as keys
      """
      if not result_set or not result_set.primary_results:
          logger.debug("Empty or null result set received")
          return []
  
      try:
          primary_result = result_set.primary_results[0]
          columns = [col.column_name for col in primary_result.columns]
  
          formatted_results = []
          for row in primary_result.rows:
              record = {}
              for i, value in enumerate(row):
                  record[columns[i]] = value
              formatted_results.append(record)
  
          logger.debug("Query results formatted", row_count=len(formatted_results), columns=columns)
          return formatted_results
      except Exception as e:
          logger.error(
              "Error formatting query results",
              error=str(e),
              exception_type=type(e).__name__
          )
          raise