Google Calendar day summary tool

What it is

This n8n workflow is a tool for an AI agent, and another workflow has to call it. The caller passes the user’s question as query, such as what is on tomorrow. Seven nodes run in a line. The first asks gpt-4o which day the question means, from n8n’s own clock, and gets that day and the next one back. A Google Calendar node reads the events between them, ten at most. Two more nodes keep each event’s name and times and have gpt-4o write a note on it. The last two join the notes into a response field.

Who it suits

People who build an n8n agent that answers questions about a schedule, from a chat or a voice message, and want the calendar part ready as one tool. Anyone with no agent can still use it from a scheduled workflow that calls it with query set to today.

Where to use it

Any n8n that can reach Google Calendar and OpenAI will do, on n8n Cloud or on a server of your own. Nothing happens until something calls it. An agent’s Call n8n Workflow Tool node is the usual caller, behind a chat or a Telegram bot. An Execute Workflow node in a morning schedule works too, with the next node sending the reply on.

Setup

Get it saves a zip with workflow.json and Mindket’s setup notes in your downloads folder. Have two things ready: an OpenAI key, and a Google account whose calendar n8n may read.

1. In n8n, create a workflow, open its menu, choose Import from File and pick workflow.json.
2. Add an OpenAI credential and select it in Find Current Date and in Summarize Calendar.
3. Add a Google Calendar OAuth2 credential and select it in Google Calendar.
4. In the same node, pick your calendar in the Calendar field, which holds YOUR_CALENDAR_ID.
5. Save, then add the node that runs it to the calling workflow. For an agent, give the tool one line saying what it does, because the agent reads that line to decide when to use it.

The caller passes one text field and gets one back. The agent’s words arrive as query, and the notes leave as response:

in:  { "query": "What is on my calendar tomorrow?" }
out: { "response": "<a short note on each event>" }

How to use it

Ask the agent about a day in its own words. It hands the question to the tool, which works out the date. The agent then builds its answer from response. To try it without an agent, pin an item with a query field on Execute Workflow Trigger and run the workflow from the editor.

Example

Ask about tomorrow on a day that holds a stand-up and a dentist visit. Find Current Date answers with the two dates below, Google Calendar returns both events, and Summarize Calendar writes a note on each, which the agent gets in response:

{
  "Requested day": "2026-11-03",
  "Next day": "2026-11-04"
}

For newcomers and experts

If you are new. A sub-workflow is an ordinary workflow that starts from Execute Workflow Trigger and waits to be called. Run it on its own first. Every node shows what it received and what it sent, so a wrong date or an empty calendar turns up there before an agent is involved.

For experts. Both OpenAI nodes use gpt-4o, and the note-writing node makes one call per event, so a full day costs eleven calls. A question about next week still gets one day’s range, because the date node is asked for a single day. Raise limit for busier days. Rewrite the date node’s prompt if the agent should ask for longer ranges.

Good to know

Each question costs money. The event names leave your calendar for OpenAI too.

• Billing: OpenAI charges for the date call and for each event’s note
• All-day events: Google gives them a date and no time, and the workflow reads times, so their start and end arrive empty
• Time zone: the day comes from n8n’s clock, so check the time zone in the workflow’s settings
• Credentials: the JSON holds none, and nothing from its author’s account