Start at https://support.atlassian.com/jira-cloud-administration/docs/configure-issue-security-schemes/
You're going to need to think about how you identify issues as belonging to specific agents, that's not something we can help you with directly. But there is one easy scheme we can suggest - if you have a security level that says "assignee can see the issue", you can use the assignee to do it dynamically (and probably automate "set security level when issue assigned")
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