The standard criteria to determine if and when an Initial Response or subsequent Update has been provided to the customer is the presence of a public comment made on the ticket by the agent.
However, depending upon the way in which your Customer Support process operates and how you communicate with your customers it might be the case that a public comment shouldn't be used as the criteria for this purpose.
The CloudSET extension framework therefore provides the option to achieve this as described in the following steps.
Configure your Model options to Ignore Public Comments
Depending upon the model in use as part of your setup (3) it will be possible to select the option to ignore public comments as the criteria to determine if an initial response has been made (4).
Selecting this option will ensure that the response timer will continue running and the SLA for the response event will not be passed if and when a public comment is applied to the ticket.
If this option is selected it will also be necessary to select the option to record the first response by another method to enable the use of alternative custom rules for this purpose.
*Note: a similar set of options is available against the Update event if opting to measure the SLA performance for regular updates against the tikcet.
Please see the article named Implementing Support for an Initial Response or Update made externally to Zendesk (e.g. by Phone) for for details on how to achieve this.