Salesforce allows you to make AI responses smarter by using Apex merge fields in a Field Generation Prompt Template. This helps Einstein Generative AI use real-time data from your org when creating AI-generated content.
Let’s understand this with a simple example.
Business Use Case
Imagine your sales team wants to see a summary of all open cases for a customer before making a sales call. Instead of checking multiple records, Salesforce AI can automatically generate this summary and store it on the Account record.
To do this, we use:
A Field Generation Prompt Template
An Apex class to fetch open case data
Using Apex with Prompt Templates
An Apex class can be written to:
Accept an Account as input
Find all open Cases related to that Account
Prepare the case details as text
Send this text to the AI model as part of the prompt
This Apex class is exposed to Prompt Builder using the @InvocableMethod annotation. Once exposed, it can be selected as a resource inside a prompt template.
Key parts explained:
@InvocableMethod
Required to expose the method to Prompt Builder
label
This is the name you see in the UI (“Open Cases”)
description
Explains what the method does
CapabilityType
Tells Salesforce this method is used for Field Generation Prompt Templates
Method signature rules:
Must be static
Must accept a List of Request
Must return a List of Response
Request Inner Class (Input)
public class Request {
@InvocableVariable(required=true)
public Account RelatedEntity;
}
What this does:
Defines what input the method receives
In this case, it receives an Account record
Important points:
@InvocableVariable exposes the variable to Salesforce
RelatedEntity is automatically populated when the prompt runs
This allows the method to know which Account to process
Response Inner Class (Output)
public class Response {
@InvocableVariable
public String Prompt;
}
What this does:
Defines what data is sent back to Prompt Builder
The Prompt field holds the final text
Einstein uses this text as input context for the LLM
Creating the Field Generation Prompt Template
After the Apex class is ready, follow these steps in Prompt Builder:
Create a custom field on the Account object
Example: Open Case Summary (Text Area – Long)
Open Prompt Builder and create a new prompt template
Prompt Template Type: Field Generation
Object: Account
Object Field: Open Case Summary
Paste a sample “Summarize open cases” prompt into the workspace
Insert resources into the prompt:
Add Account ID as a merge field
Add the Apex resource that fetches open case details
The Apex class provides live case data, and Einstein Generative AI uses it to generate a clear summary.
Final Result
When the prompt runs:
Salesforce calls the Apex class
Open case details are added to the prompt
Einstein Generative AI creates a summary
The summary is saved in the Account field
This gives users up-to-date, AI-generated insights without manual effort.
