There is documentation on agent naming
https://docops.ca.com/ca-apm/10-7/en/implementing-agents/java-agent/configure-java-monitoring/java-agent-naming/
There is no mechanism we can rely on in Tomcat to derive a name for the agent, unlike domain/server or cell/node information in Weblogic/WebSphere, so a Tomcat agent has to be named manually.
The name "Tomcat Agent" will be coming from the agent profile (Method 5 as described in the documentation), so you can change the name there to what you want,
Assuming each Tomcat application will have its own profile, you can use that method to give unique names.
The documentation mentions other ways that the name can be created based on system properties, if these are available and meaningful.
The name can, or example, be specified as part of JVM arguments as again mentioned in the documentation.