how can we add case comment in the prompt builder?

Hi @Dhirendra verma You can use Case Comments in Prompt Builder, but if the CaseComments related list is missing, please check a few things.

Try these steps:

1. Go to Setup → Object Manager → Case → Page Layouts.
2. Open the Case page layout and check whether the Case Comments related list is added.
3. In Prompt Builder, confirm that your prompt template uses Case as its input object.
4. Click Insert Resource → Case and look for CaseComments under related lists.
5. Also verify that your user has Read access to the Case Comment records.

Salesforce's Trailhead example uses this related list:

{!$RelatedList:Case.CaseComments.Records} 

If it's still not showing:

You can use a Template-Triggered Prompt Flow as an alternative.

• Use Get Records on the Case Comment object.
• Filter using Parent ID = current Case ID.
• Loop through the comments and collect their CommentBody values.
• Use Add Prompt Instructions to pass the comments into the prompt template.

Useful Salesforce Documentation:

• Quick Start: Prompt Builder – Case Comments
• Build a Field Generation Prompt Template Using Flow
• Grounding with Related List Merge Fields

Related Trailblazer Discussion:

• Case Resource Missing in Prompt Builder

Check the Case page layout first. Prompt Builder only displays supported related lists available on the relevant page layout. If CaseComments still doesn't appear, the Flow approach is a good alternative.

Hope this helps!