The 'HTTP Scripting Tool User Agent' detection rule designed for Splunk analyzes web access logs specifically from Nginx. It focuses on identifying non-standard user agents such as security tools, scripting languages, and automation frameworks that may be indicative of malicious activities. By executing a Splunk query against the Nginx access logs, the rule first normalizes the user agent strings and cross-references them against a lookup of known scripting tools. It then filters for and counts occurrences of these non-standard user agents, providing statistics such as first and last observed times and tools used. The primary objective is to flag potentially suspicious interactions with web endpoints, which may highlight attempts to exploit vulnerabilities or perform reconnaissance through unconventional means.