Liam Nicholls

It is possible via the API to apply internal comments.

I realise not everyone has the resources to make use of the Zendesk API. We have 3rd party systems that update Zendesk tickets by way of an internal comment.

One 3rd party app we've integrated with is Github which will update Zendesk tickets with an internal comment when a fix for an issue in place. So technically this is feasible.

Zendesk should allow you could create triggers to do this via the front end, as not every organisation has the resources to make use of the API.