I have this App.
https://splunkbase.splunk.com/app/3525/#/details
Almost everyone does and I don't see how I can add my .json into the message body so this active action has my Splunk search results link or RAW log in the .json message. There must be a TAG I am not using because the script in this App has the JSON library in the code.
The Slack Webhook Alert supports the same inline tokens as the email alert, as detailed in https://docs.splunk.com/Documentation/Splunk/7.0.2/Alert/EmailNotificationTokens.
For example, for your license usage example, if your search returns a results with a usage_gb
field, you can set your Slack message as follows:
We used $result.usage_gb$ GB of our license today.
Hope this helps.