ServiceNow MCP Server

Instructions

Implementation Reference

• src/servicenow_mcp/tools/changeset_tools.py:616-692 (handler)

  The core handler function implementing the publish_changeset tool. It validates input parameters, retrieves ServiceNow instance details, and performs a PATCH request to set the changeset state to 'published'.

  def publish_changeset(
      auth_manager: AuthManager,
      server_config: ServerConfig,
      params: Union[Dict[str, Any], PublishChangesetParams],
  ) -> Dict[str, Any]:
      """
      Publish a changeset in ServiceNow.
  
      Args:
          auth_manager: The authentication manager.
          server_config: The server configuration.
          params: The parameters for publishing a changeset. Can be a dictionary or a PublishChangesetParams object.
  
      Returns:
          The published changeset.
      """
      # Unwrap and validate parameters
      result = _unwrap_and_validate_params(
          params, 
          PublishChangesetParams, 
          required_fields=["changeset_id"]
      )
      
      if not result["success"]:
          return result
      
      validated_params = result["params"]
      
      # 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"
      
      # Prepare the request data for the publish action
      data = {
          "state": "published",
      }
      
      # Add publish notes if provided
      if validated_params.publish_notes:
          data["description"] = validated_params.publish_notes
      
      # Make the API request
      url = f"{instance_url}/api/now/table/sys_update_set/{validated_params.changeset_id}"
      
      try:
          response = requests.patch(url, json=data, headers=headers)
          response.raise_for_status()
          
          result = response.json()
          
          return {
              "success": True,
              "message": "Changeset published successfully",
              "changeset": result["result"],
          }
      except requests.exceptions.RequestException as e:
          logger.error(f"Error publishing changeset: {e}")
          return {
              "success": False,
              "message": f"Error publishing changeset: {str(e)}",
          }

• src/servicenow_mcp/tools/changeset_tools.py:66-71 (schema)

  Pydantic BaseModel defining the input schema for the publish_changeset tool, including required changeset_id and optional publish_notes.

  class PublishChangesetParams(BaseModel):
      """Parameters for publishing a changeset."""
  
      changeset_id: str = Field(..., description="Changeset ID or sys_id")
      publish_notes: Optional[str] = Field(None, description="Notes for publishing")

• src/servicenow_mcp/utils/tool_utils.py:667-673 (registration)

  Tool registration in the get_tool_definitions() function's dictionary. Associates the tool name with its handler (publish_changeset_tool), input schema (PublishChangesetParams), return type (str), description, and serialization method.

  "publish_changeset": (
      publish_changeset_tool,
      PublishChangesetParams,
      str,
      "Publish a changeset in ServiceNow",
      "str",  # Tool returns simple message
  ),

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

  Shared helper function used by publish_changeset (and other tools) to validate and unwrap input parameters against the Pydantic schema.

  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)}",
          }

• src/servicenow_mcp/tools/changeset_tools.py:135-162 (helper)

  Helper function to retrieve the ServiceNow instance URL from either auth_manager or server_config, used by publish_changeset.

  def _get_instance_url(auth_manager: AuthManager, server_config: ServerConfig) -> Optional[str]:
      """
      Get the instance URL from either auth_manager or server_config.
  
      Args:
          auth_manager: The authentication manager.
          server_config: The server configuration.
  
      Returns:
          The instance URL or None if not found.
      """
      # Try to get instance_url from server_config
      if hasattr(server_config, 'instance_url'):
          return server_config.instance_url
      
      # Try to get instance_url from auth_manager
      if hasattr(auth_manager, 'instance_url'):
          return auth_manager.instance_url
      
      # If neither has instance_url, check if auth_manager is actually a ServerConfig
      # and server_config is actually an AuthManager (parameters swapped)
      if hasattr(server_config, 'get_headers') and not hasattr(auth_manager, 'get_headers'):
          if hasattr(auth_manager, 'instance_url'):
              return auth_manager.instance_url
      
      logger.error("Cannot find instance_url in either auth_manager or server_config")
      return None