Problem Definition

On Jira Software one can access all issues that belong to an Epic from the REST API – GET /rest/agile/1.0/epic/<epicIdOrKey>/issue.

There's no feature in Automation for Jira that provides similar ability through a smart value.

On Atlassian Cloud there's an action to lookup issues based on a JQL, which isn't available on Data Center (JIRAAUTOSERVER-53).

Suggested Solution

When acting in an Epic issue, include a field to access all issues that belong to this Epic.
This would be similar to the issue.subtasks smart value available as a list of sub-task issues – Jira smart values - lists.

Workaround

These are possible workarounds:

• Send a web-request action to GET /rest/agile/1.0/epic/<epicIdOrKey>/issue
  • https://confluence.atlassian.com/automation/jira-automation-actions-993924834.html#Jiraautomationactions-sendwebrequest
  • https://docs.atlassian.com/jira-software/REST/9.5.0/#agile/1.0/epic-getIssuesForEpic
• Branch the rule on issues in Epic.
  • https://confluence.atlassian.com/automation/branch-automation-rules-to-perform-actions-on-related-issues-993924648.html