ServiceNow MCP Server

Instructions

Implementation Reference

• src/servicenow_mcp/tools/changeset_tools.py:286-366 (handler)

  Main handler function implementing the get_changeset_details tool logic, fetches changeset and its changes from ServiceNow REST APIs.

  def get_changeset_details(
      auth_manager: AuthManager,
      server_config: ServerConfig,
      params: Union[Dict[str, Any], GetChangesetDetailsParams],
  ) -> Dict[str, Any]:
      """
      Get detailed information about a specific changeset.
  
      Args:
          auth_manager: The authentication manager.
          server_config: The server configuration.
          params: The parameters for getting changeset details. Can be a dictionary or a GetChangesetDetailsParams object.
  
      Returns:
          Detailed information about the changeset.
      """
      # Unwrap and validate parameters
      result = _unwrap_and_validate_params(
          params, 
          GetChangesetDetailsParams, 
          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",
          }
      
      # Make the API request
      url = f"{instance_url}/api/now/table/sys_update_set/{validated_params.changeset_id}"
      
      try:
          response = requests.get(url, headers=headers)
          response.raise_for_status()
          
          result = response.json()
          
          # Get the changeset details
          changeset = result.get("result", {})
          
          # Get the changes in this changeset
          changes_url = f"{instance_url}/api/now/table/sys_update_xml"
          changes_params = {
              "sysparm_query": f"update_set={validated_params.changeset_id}",
          }
          
          changes_response = requests.get(changes_url, params=changes_params, headers=headers)
          changes_response.raise_for_status()
          
          changes_result = changes_response.json()
          changes = changes_result.get("result", [])
          
          return {
              "success": True,
              "changeset": changeset,
              "changes": changes,
              "change_count": len(changes),
          }
      except requests.exceptions.RequestException as e:
          logger.error(f"Error getting changeset details: {e}")
          return {
              "success": False,
              "message": f"Error getting changeset details: {str(e)}",
          }

• src/servicenow_mcp/tools/changeset_tools.py:34-38 (schema)

  Pydantic model defining the input parameters for the tool, requiring 'changeset_id'.

  class GetChangesetDetailsParams(BaseModel):
      """Parameters for getting changeset details."""
  
      changeset_id: str = Field(..., description="Changeset ID or sys_id")

• src/servicenow_mcp/utils/tool_utils.py:582-588 (registration)

  Registers the tool in the central tool_definitions dictionary used by the MCP server, specifying handler, params model, description, and serialization.

  "get_changeset_details": (
      get_changeset_details_tool,
      GetChangesetDetailsParams,
      str,  # Expects JSON string
      "Get detailed information about a specific changeset",
      "json",  # Tool returns list/dict
  ),

• src/servicenow_mcp/tools/__init__.py:143-143 (registration)

  Includes the tool in the __all__ export list of the tools module.

  "get_changeset_details",

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

  Helper function used by the handler 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)}",
          }