Build an Automated Email Drafting AI Agent with n8n and OpenAI

System Prompt for Email Agent

User Prompt Template

Getting Started & Workflow Setup

1. Click the '+' icon at the top of the screen and select 'Workflow'.
2. Choose the project you want to use (e.g., 'Personal Project').
3. Click the '+' button in the middle of the canvas to add your first node.
4. Search for 'Gmail' in the search bar and select the node.
5. Select 'On Message Received' as the main Trigger.
6. Click the pencil icon to connect your Gmail account via 'Sign in with Google'.
7. Grant the necessary permissions required by Google for n8n access.
8. Ensure the connection status shows a green check mark.

Configuring the OpenAI Node for Email Analysis

1. Click the '+' button after the Gmail node and search for 'OpenAI'.
2. Choose the 'Message a Model' action from the options list.
3. Click the '+' button under 'Credential for OpenAI API' to enter your API Key.
4. Select the 'gpt-4o-mini' model (or any other model available in your account).
5. Change the message type to 'Assistant' to set the System Prompt.
6. Enter your system instructions in the prompt field.
7. Change the 'Message' input type from 'Fixed' to 'Expression' to enable dynamic data.
8. Toggle the data view to 'Schema' format to simplify the drag-and-drop process.
9. Drag the 'From' (Sender Email), 'Subject' (Subject), and 'Snippet' (Content) data from the Gmail output into the OpenAI User Prompt field.

Automatically Generating Reply Drafts

1. Click the '+' button after the OpenAI node and select 'Gmail' again.
2. Set Resource to 'Draft' and Operation to 'Create'.
3. Use the same Gmail account you connected earlier.
4. Change the 'Message' setting to 'Expression'.
5. Drag the 'Content' output from the OpenAI node into the Gmail 'Message' field.
6. Click 'Add Option' and select 'Thread ID'.
7. Drag the 'Thread ID' from the original Gmail Trigger into the 'Thread ID' field to keep the reply within the same thread.
8. Drag the 'Subject' from the original Gmail Trigger into the Gmail Draft subject field.
9. Click 'Test Step' to test the workflow and check your Gmail Drafts folder.
10. Activate the workflow by switching the 'Active' toggle in the top right.