I think these are the only parameter available in script alert action
Arg Environment Variable Value
0 SPLUNK_ARG_0 Script name
1 SPLUNK_ARG_1 Number of events returned
2 SPLUNK_ARG_2 Search terms
3 SPLUNK_ARG_3 Fully qualified query string
4 SPLUNK_ARG_4 Name of report
5 SPLUNK_ARG_5 Trigger reason
For example, "The number of events was greater than 1."
6 SPLUNK_ARG_6 Browser URL to view the report.
7 SPLUNK_ARG_7 Not used for historical reasons.
8 SPLUNK_ARG_8 File in which the results for the search are stored.
Contains raw results in gzip file format.