Tool system, external system, determination method, and non-transitory storage medium

A tool system comprising:

• a tool being configured to perform a fastening operation and including a first communications interface;
• and
• an external system including a second communications interface,
• the first communications interface being configured to transmit result information, including a fastening torque of the fastening operation and including a work order number, to the external system with progress of the work,
• the second communications interface being configured to receive the result information from the tool,
• the external system being configured to make a storage device store the result information received by the second communications interface,
• at least one of the tool or the external system further including a processor,
• the processor being configured to determine, based on progress information indicating the progress of the work being performed by the tool and the result information stored in the storage device, what part of the result information the second communications interface has failed to receive.