ServiceNow MCP Server

Instructions

Implementation Reference

• src/servicenow_mcp/tools/workflow_tools.py:300-357 (handler)

  The handler function that executes the tool: queries ServiceNow API for wf_workflow_version table filtered by workflow_id, handles pagination and errors.

  def list_workflow_versions(
      auth_manager: AuthManager,
      server_config: ServerConfig,
      params: Dict[str, Any],
  ) -> Dict[str, Any]:
      """
      List versions of a specific workflow.
      
      Args:
          auth_manager: Authentication manager
          server_config: Server configuration
          params: Parameters for listing workflow versions
          
      Returns:
          Dict[str, Any]: List of workflow versions
      """
      # Unwrap parameters if needed
      params = _unwrap_params(params, ListWorkflowVersionsParams)
      
      # Get the correct auth_manager and server_config
      try:
          auth_manager, server_config = _get_auth_and_config(auth_manager, server_config)
      except ValueError as e:
          logger.error(f"Error getting auth and config: {e}")
          return {"error": str(e)}
      
      workflow_id = params.get("workflow_id")
      if not workflow_id:
          return {"error": "Workflow ID is required"}
      
      # Convert parameters to ServiceNow query format
      query_params = {
          "sysparm_query": f"workflow={workflow_id}",
          "sysparm_limit": params.get("limit", 10),
          "sysparm_offset": params.get("offset", 0),
      }
      
      # Make the API request
      try:
          headers = auth_manager.get_headers()
          url = f"{server_config.instance_url}/api/now/table/wf_workflow_version"
          
          response = requests.get(url, headers=headers, params=query_params)
          response.raise_for_status()
          
          result = response.json()
          return {
              "versions": result.get("result", []),
              "count": len(result.get("result", [])),
              "total": int(response.headers.get("X-Total-Count", 0)),
              "workflow_id": workflow_id,
          }
      except requests.RequestException as e:
          logger.error(f"Error listing workflow versions: {e}")
          return {"error": str(e)}
      except Exception as e:
          logger.error(f"Unexpected error listing workflow versions: {e}")
          return {"error": str(e)}

• src/servicenow_mcp/tools/workflow_tools.py:40-46 (schema)

  Pydantic BaseModel for input parameters validation: requires workflow_id, optional limit and offset.

  class ListWorkflowVersionsParams(BaseModel):
      """Parameters for listing workflow versions."""
      
      workflow_id: str = Field(..., description="Workflow ID or sys_id")
      limit: Optional[int] = Field(10, description="Maximum number of records to return")
      offset: Optional[int] = Field(0, description="Offset to start from")

• src/servicenow_mcp/utils/tool_utils.py:561-567 (registration)

  Tool registration entry in get_tool_definitions(): maps name to handler (aliased import), schema, return type hint, description, and JSON serialization method.

  "list_workflow_versions": (
      list_workflow_versions_tool,
      ListWorkflowVersionsParams,
      str,  # Expects JSON string
      "List workflow versions from ServiceNow",
      "json",  # Tool returns list/dict
  ),

• src/servicenow_mcp/tools/workflow_tools.py:126-135 (helper)

  Helper function to normalize input params to dict, unwrapping Pydantic models if needed; used at line 317 in handler.

  def _unwrap_params(params: Any, param_class: Type[T]) -> Dict[str, Any]:
      """
      Unwrap parameters if they're wrapped in a Pydantic model.
      This helps handle cases where the parameters are passed as a model instead of a dict.
      """
      if isinstance(params, dict):
          return params
      if isinstance(params, param_class):
          return params.dict(exclude_none=True)
      return params

• src/servicenow_mcp/tools/workflow_tools.py:138-181 (helper)

  Helper function to correctly order and extract AuthManager and ServerConfig from arguments, handling possible swaps; used in handler.

  def _get_auth_and_config(
      auth_manager_or_config: Union[AuthManager, ServerConfig],
      server_config_or_auth: Union[ServerConfig, AuthManager],
  ) -> tuple[AuthManager, ServerConfig]:
      """
      Get the correct auth_manager and server_config objects.
      
      This function handles the case where the parameters might be swapped.
      
      Args:
          auth_manager_or_config: Either an AuthManager or a ServerConfig.
          server_config_or_auth: Either a ServerConfig or an AuthManager.
          
      Returns:
          tuple[AuthManager, ServerConfig]: The correct auth_manager and server_config.
          
      Raises:
          ValueError: If the parameters are not of the expected types.
      """
      # Check if the parameters are in the correct order
      if isinstance(auth_manager_or_config, AuthManager) and isinstance(server_config_or_auth, ServerConfig):
          return auth_manager_or_config, server_config_or_auth
      
      # Check if the parameters are swapped
      if isinstance(auth_manager_or_config, ServerConfig) and isinstance(server_config_or_auth, AuthManager):
          return server_config_or_auth, auth_manager_or_config
      
      # If we get here, at least one of the parameters is not of the expected type
      if hasattr(auth_manager_or_config, "get_headers"):
          auth_manager = auth_manager_or_config
      elif hasattr(server_config_or_auth, "get_headers"):
          auth_manager = server_config_or_auth
      else:
          raise ValueError("Cannot find get_headers method in either auth_manager or server_config")
      
      if hasattr(auth_manager_or_config, "instance_url"):
          server_config = auth_manager_or_config
      elif hasattr(server_config_or_auth, "instance_url"):
          server_config = server_config_or_auth
      else:
          raise ValueError("Cannot find instance_url attribute in either auth_manager or server_config")
      
      return auth_manager, server_config