Gmail meeting requests answered with free calendar slots

Gmail meeting requests answered with free calendar slots

An n8n workflow that watches Gmail for unread mail. An OpenAI model decides whether a message asks for a meeting or a
call. When it does, an AI agent reads your Google Calendar, writes a reply that proposes a time, and the reply goes back to
the sender.

What is inside

• workflow.json: the workflow as n8n exports it, 17 nodes beside 4 sticky notes. It holds no credential.
• README.md: these notes.

What we changed from the original copy

Mindket changed a few details so the file runs today:

• Both chat model nodes named gpt-4, which OpenAI shut down on 23 October 2026. Mindket's copy names gpt-5.6-sol, the
  replacement OpenAI gives for it. Both nodes had a temperature set, 0.1 and 0. Mindket could not confirm that the new
  model takes one, so it left both out.
• The calendar node held a sample address. It now reads <YOUR_CALENDAR_EMAIL>.
• The agent's prompt joined its lines with a typed backslash and the letter n, which a model reads as two characters. It
  now uses real line breaks.
• No credential is inside.

Before you start

• An n8n instance, on n8n Cloud or your own server.
• An OpenAI API key.
• A Google account, for a Gmail OAuth2 credential and a Google Calendar OAuth2 credential.

Set it up

1. In n8n, create a workflow, open its menu and choose Import from File. Pick workflow.json.
2. Add a Gmail OAuth2 credential and select it in Gmail Trigger, Mark as read and Send Reply.
3. Add an OpenAI credential and select it in Chat OpenAI and Chat OpenAI1.
4. Add a Google Calendar OAuth2 credential and select it in Google Calendar. Replace <YOUR_CALENDAR_EMAIL> with the
   address of the calendar to read.
5. Save the workflow before you test. Workflow Tool runs this same workflow by its id, {{ $workflow.id }}. If you split
   the workflow in two, put the second workflow's id there.
6. Send yourself an email that asks for a meeting, then run Gmail Trigger once.

How a run goes

1. Gmail Trigger checks Gmail every minute for unread mail, with spam and trash left out.
2. Classify appointment asks Chat OpenAI whether the subject and the snippet suggest a meeting or a call. With
   Structured Output Parser, the answer is a field is_appointment that is true or false.
3. Is appointment request lets only the true ones through.
4. Agent is a Conversational agent, version 1, with Chat OpenAI1 as its model. Its prompt holds the sender, the subject,
   the snippet and the date and time now. It can call Workflow Tool, named Calendar_Availability.
5. The tool runs the other branch of this workflow, which starts at Execute Workflow Trigger. The node Google Calendar
   reads every event from one day back to one month ahead. Then Filter only confirmed and with set time keeps confirmed
   events that have a start time. After that, Extract start, end and name writes a start, an end, a name and a sort key.
   Next, Sort orders them, and Format response and Stringify Response hand them back as one text.
6. The agent's instructions tell it to aim for a specific time, to leave 15 minutes after the previous meeting and always to
   propose a new time when you are busy.
7. Send Reply answers the sender only, and Mark as read marks the email as read.

Change the look

• What counts as a meeting request: the prompt in Classify appointment.
• The rules for the reply: the system message under the options of Agent.
• How far the calendar is read: timeMin and timeMax in Google Calendar.
• Draft first: swap Send Reply for a Gmail step that makes a draft, and read each one before it goes.
• The models: Chat OpenAI and Chat OpenAI1.

Good to know

• The reply goes out by itself. Send Reply sends the agent's text with no check, and the model can be wrong about your
  calendar. Any unread mail the model takes for a meeting request gets an answer, including newsletters and automatic
  messages.
• The model reads only the snippet, the short preview Gmail gives, and not the whole email.
• Each unread email costs one model call, and a meeting request costs at least one more, plus a further call when the agent
  asks for your calendar.
• Your calendar's event titles and times go to OpenAI in the tool's answer, and so do the sender, the subject and the snippet.
• n8n marks the agent type used here as deprecated and says it is removed in version 3. A newer AI Agent node replaces it.
• The workflow reads one calendar, and its dates are written in the time zone n8n uses.
• The JSON holds no credential.