ServiceNow MCP Server

Instructions

Implementation Reference

• src/servicenow_mcp/tools/change_tools.py:860-958 (handler)

  Implements the core logic for the reject_change tool: validates parameters, finds approval record, updates approval to rejected, sets change request state to canceled with rejection reason in work notes.
  def reject_change( auth_manager: AuthManager, server_config: ServerConfig, params: Dict[str, Any], ) -> Dict[str, Any]: """ Reject a change request in ServiceNow. Args: auth_manager: The authentication manager. server_config: The server configuration. params: The parameters for rejecting a change request. Returns: The result of the rejection. """ # Unwrap and validate parameters result = _unwrap_and_validate_params( params, RejectChangeParams, required_fields=["change_id", "rejection_reason"] ) 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", } # First, find the approval record approval_query_url = f"{instance_url}/api/now/table/sysapproval_approver" query_params = { "sysparm_query": f"document_id={validated_params.change_id}", "sysparm_limit": 1, } try: approval_response = requests.get(approval_query_url, headers=headers, params=query_params) approval_response.raise_for_status() approval_result = approval_response.json() if not approval_result.get("result") or len(approval_result["result"]) == 0: return { "success": False, "message": "No approval record found for this change request", } approval_id = approval_result["result"][0]["sys_id"] # Now, update the approval record to rejected approval_update_url = f"{instance_url}/api/now/table/sysapproval_approver/{approval_id}" headers["Content-Type"] = "application/json" approval_data = { "state": "rejected", "comments": validated_params.rejection_reason, } approval_update_response = requests.patch(approval_update_url, json=approval_data, headers=headers) approval_update_response.raise_for_status() # Finally, update the change request state to "canceled" change_url = f"{instance_url}/api/now/table/change_request/{validated_params.change_id}" change_data = { "state": "canceled", # This may vary depending on ServiceNow configuration "work_notes": f"Change request rejected: {validated_params.rejection_reason}", } change_response = requests.patch(change_url, json=change_data, headers=headers) change_response.raise_for_status() return { "success": True, "message": "Change request rejected successfully", } except requests.exceptions.RequestException as e: logger.error(f"Error rejecting change: {e}") return { "success": False, "message": f"Error rejecting change: {str(e)}", }
• src/servicenow_mcp/tools/change_tools.py:99-105 (schema)

  Pydantic model defining the input parameters for the reject_change tool: required change_id and rejection_reason, optional approver_id.
  class RejectChangeParams(BaseModel): """Parameters for rejecting a change request.""" change_id: str = Field(..., description="Change request ID or sys_id") approver_id: Optional[str] = Field(None, description="ID of the approver") rejection_reason: str = Field(..., description="Reason for rejection")
• src/servicenow_mcp/utils/tool_utils.py:482-488 (registration)

  Registers the reject_change tool in the central tool_definitions dictionary, mapping name to (function, params model, return type, description, serialization).
  "reject_change": ( reject_change_tool, RejectChangeParams, str, "Reject a change request", "str", # Tool returns simple message ),
• src/servicenow_mcp/tools/__init__.py:125-125 (registration)

  Includes reject_change in the __all__ export list for the tools module.
  "reject_change",
• src/servicenow_mcp/tools/change_tools.py:107-159 (helper)

  Helper function used by reject_change (and other tools) to unwrap, validate parameters against Pydantic model, and check required fields.
  def _unwrap_and_validate_params(params: Any, model_class: Type[T], required_fields: List[str] = None) -> Dict[str, Any]: """ Helper function to unwrap and validate parameters. Args: params: The parameters to unwrap and validate. model_class: The Pydantic model class to validate against. required_fields: List of required field names. Returns: A tuple of (success, result) where result is either the validated parameters or an error message. """ # Handle case where params might be wrapped in another dictionary if isinstance(params, dict) and len(params) == 1 and "params" in params and isinstance(params["params"], dict): logger.warning("Detected params wrapped in a 'params' key. Unwrapping...") params = params["params"] # Handle case where params might be a Pydantic model object if not isinstance(params, dict): try: # Try to convert to dict if it's a Pydantic model logger.warning("Params is not a dictionary. Attempting to convert...") params = params.dict() if hasattr(params, "dict") else dict(params) except Exception as e: logger.error(f"Failed to convert params to dictionary: {e}") return { "success": False, "message": f"Invalid parameters format. Expected a dictionary, got {type(params).__name__}", } # Validate required parameters are present if required_fields: for field in required_fields: if field not in params: return { "success": False, "message": f"Missing required parameter '{field}'", } try: # Validate parameters against the model validated_params = model_class(**params) return { "success": True, "params": validated_params, } except Exception as e: logger.error(f"Error validating parameters: {e}") return { "success": False, "message": f"Error validating parameters: {str(e)}", }