How to customize Participant Step dialog with dynamic checkbox values from workflow metadata?

Hi all,

I'm working on an AEMaaCS workflow and would like to implement a custom Participant Step dialog with dynamic data coming from a previous Process Step.

Here is my use case:

1. An editor starts a workflow on a Content Fragment

2. Editor receives a notification and completes the first task

3. A custom Process Step collects all referenced nodes under the Content Fragment and stores them into workflow metadata like below:

   item.getWorkflow().getWorkflowData().getMetaDataMap()
   .put("discoveredNodePaths", collectedPaths.toArray(new String[0]));
    

4. In the next Participant Step:

   • Editor opens the task from Inbox
   • A dialog should display all discovered node paths as a checkbox group
   • Editor selects some nodes and clicks "Ok"
   • The selected nodes should be saved back into workflow metadata

5. Next Reviewer step:

   • Reviewer opens task and sees selected nodes
   • Can approve or reject

6. If approved, a Process Step publishes all selected nodes

My questions is about step4:

1. How can I customize the Participant Step dialog in AEMaaCS?

   • Especially how to build a dynamic checkbox group based on workflow metadata?

2. How can I read workflow metadata inside the dialog (Granite UI / Coral UI)?

3. After user clicks "Ok", how can I persist selected values back into workflow metadata for next steps?

4. Is this achievable with standard Participant Step dialog configuration,
   or do I need a completely custom Inbox action / UI extension?

Any guidance or example would be greatly appreciated. Thanks!