ServiceNow MCP Server

Instructions

Implementation Reference

• src/servicenow_mcp/tools/changeset_tools.py:368-446 (handler)

  Main handler function implementing the create_changeset tool. Validates input parameters using Pydantic model, constructs the ServiceNow API request to create a new changeset in the sys_update_set table, handles authentication and errors, and returns the result.

  def create_changeset(
      auth_manager: AuthManager,
      server_config: ServerConfig,
      params: Union[Dict[str, Any], CreateChangesetParams],
  ) -> Dict[str, Any]:
      """
      Create a new changeset in ServiceNow.
  
      Args:
          auth_manager: The authentication manager.
          server_config: The server configuration.
          params: The parameters for creating a changeset. Can be a dictionary or a CreateChangesetParams object.
  
      Returns:
          The created changeset.
      """
      # Unwrap and validate parameters
      result = _unwrap_and_validate_params(
          params, 
          CreateChangesetParams, 
          required_fields=["name", "application"]
      )
      
      if not result["success"]:
          return result
      
      validated_params = result["params"]
      
      # Prepare the request data
      data = {
          "name": validated_params.name,
          "application": validated_params.application,
      }
      
      # Add optional fields if provided
      if validated_params.description:
          data["description"] = validated_params.description
      if validated_params.developer:
          data["developer"] = validated_params.developer
      
      # Get the instance URL
      instance_url = _get_instance_url(auth_manager, server_config)
      if not instance_url:
          return {
              "success": False,
              "message": "Cannot find instance_url in either server_config or auth_manager",
          }
      
      # Get the headers
      headers = _get_headers(auth_manager, server_config)
      if not headers:
          return {
              "success": False,
              "message": "Cannot find get_headers method in either auth_manager or server_config",
          }
      
      # Add Content-Type header
      headers["Content-Type"] = "application/json"
      
      # Make the API request
      url = f"{instance_url}/api/now/table/sys_update_set"
      
      try:
          response = requests.post(url, json=data, headers=headers)
          response.raise_for_status()
          
          result = response.json()
          
          return {
              "success": True,
              "message": "Changeset created successfully",
              "changeset": result["result"],
          }
      except requests.exceptions.RequestException as e:
          logger.error(f"Error creating changeset: {e}")
          return {
              "success": False,
              "message": f"Error creating changeset: {str(e)}",
          }

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

  Pydantic BaseModel defining the input schema for the create_changeset tool, including required fields name and application, and optional description and developer.

  class CreateChangesetParams(BaseModel):
      """Parameters for creating a changeset."""
  
      name: str = Field(..., description="Name of the changeset")
      description: Optional[str] = Field(None, description="Description of the changeset")
      application: str = Field(..., description="Application the changeset belongs to")
      developer: Optional[str] = Field(None, description="Developer responsible for the changeset")

• src/servicenow_mcp/utils/tool_utils.py:635-641 (registration)

  Tool registration entry in get_tool_definitions() function, mapping 'create_changeset' to its handler, input schema, description, and serialization details for use in the MCP server.

  "create_changeset": (
      create_changeset_tool,
      CreateChangesetParams,
      str,  # Expects JSON string
      "Create a new changeset in ServiceNow",
      "json_dict",  # Tool returns Pydantic model
  ),

• src/servicenow_mcp/tools/__init__.py:36-36 (registration)

  Export of create_changeset function from tools package, making it available for import in tool_utils.py.

  create_changeset,

• src/servicenow_mcp/tools/changeset_tools.py:81-133 (helper)

  Helper function used by create_changeset (and other tools) to unwrap dictionary or Pydantic model parameters, validate against the schema, check required fields, and return validated params or error.

  def _unwrap_and_validate_params(
      params: Union[Dict[str, Any], BaseModel], 
      model_class: Type[T], 
      required_fields: Optional[List[str]] = None
  ) -> Dict[str, Any]:
      """
      Unwrap and validate parameters.
  
      Args:
          params: The parameters to unwrap and validate. Can be a dictionary or a Pydantic model.
          model_class: The Pydantic model class to validate against.
          required_fields: List of fields that must be present.
  
      Returns:
          A dictionary with success status and validated parameters or error message.
      """
      try:
          # Handle case where params is already a Pydantic model
          if isinstance(params, BaseModel):
              # If it's already the correct model class, use it directly
              if isinstance(params, model_class):
                  model_instance = params
              # Otherwise, convert to dict and create new instance
              else:
                  model_instance = model_class(**params.dict())
          # Handle dictionary case
          else:
              # Create model instance
              model_instance = model_class(**params)
          
          # Check required fields
          if required_fields:
              missing_fields = []
              for field in required_fields:
                  if getattr(model_instance, field, None) is None:
                      missing_fields.append(field)
              
              if missing_fields:
                  return {
                      "success": False,
                      "message": f"Missing required fields: {', '.join(missing_fields)}",
                  }
          
          return {
              "success": True,
              "params": model_instance,
          }
      except Exception as e:
          return {
              "success": False,
              "message": f"Invalid parameters: {str(e)}",
          }