Is it possible to customize ServiceNow for Slack? Can I view the code behind "Create an Incident"? Can I change the behavior? For example, can I cause it to set contact_type to "Slack"?
Sadly, ServiceNow for Slack in not customizable for now.
The best customization you can achieve is using slack workflows.
Check Customize incident workflows in the same link
Teams can create workflows to:
- Build a custom form with any ServiceNow field to capture a ServiceNow Incident in Slack
- Automatically create incident channels
- Send specific users messages in Slack when an incident is created from a workflow
- Leverage steps from other apps to trigger a ServiceNow Incident in response to an event in Slack
Limitation of workflows is that you can only associate it with a single channel.