How can I identify event called via user OR system generated, If I checked on generated text file from xero webhooks using PHP?

Question

I integrated Xero with webhook on my system. Every invoice-related change or create a new invoice then a new generated text file. How can I identify transaction was generated by the system(via Xero application login) OR via integrated API from my system?

If I checked the log from the application then separate both.

But I need to add it every time in a generated text file when calling webhook.

System log

Generated text file