How to integrate Google Calendar MCP with Hermes

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Introduction

Hermes is a 24/7 autonomous agent that lives on your computer or server — it remembers what it learns and evolves as your usage grows.

This guide explains the easiest and most robust way to connect your Google Calendar account to Hermes. You can do this through either Composio Connect CLI or Composio Connect MCP. For personal use we recommend the CLI, but you won't go wrong with MCP either.

Also integrate Google Calendar with

What is Composio Connect?

Composio Connect is a consumer offering that lets anyone plug 1,000+ applications directly into their agent harness — including Hermes. It can:

  • Search and load tools from relevant toolkits on-demand, reducing context usage.
  • Chain multiple tools to accomplish complex workflows via a remote workbench, without excessive back-and-forth with the LLM.
  • Manage app authentication end-to-end with zero manual overhead.

Integrating Google Calendar with Hermes

Using Composio Connect CLI

1. Install the Composio CLI

Run the install script directly, or paste https://composio.dev/hermes into your Hermes chat box to have it installed for you.

bash
curl -fsSL https://composio.dev/install | bash
Hermes authenticating with Composio

2. Authenticate

Once the CLI is installed, ask Hermes to authenticate with Composio.

3. Connect to Google Calendar

Ask your agent to connect to Google Calendar, or simply request any Google Calendar-related task. Hermes will prompt you to authenticate and authorize access.

4. Done. You're all set with a new Google Calendar connection.

Using Composio Connect MCP

1. Get your MCP URL and API Key

Go to dashboard.composio.dev and copy your Connect MCP URL and API key.

Copy MCP URL and API key from Composio dashboard

What is the Google Calendar MCP server, and what's possible with it?

The Google Calendar MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Google Calendar account. It provides structured and secure access to your calendars and events, so your agent can schedule meetings, create or modify events, list upcoming appointments, and manage calendars—all on your behalf.

  • Automated event creation and scheduling: Easily instruct your agent to add new events, meetings, or reminders with specific times, attendees, and details.
  • Event listing and agenda overview: Have your agent list all upcoming, past, or filtered events on any of your calendars to keep you on top of your schedule.
  • Calendar management and customization: Direct your agent to create new calendars, update calendar details, or even insert calendars into your list for better organization.
  • Event updating and deletion: Let your agent modify existing events or remove events that are no longer needed, keeping your calendar up to date.
  • Complete calendar clearing: Ask your agent to clear all events from a primary calendar or delete secondary calendars entirely when you need a fresh start.

Supported Tools & Triggers

Tools
Triggers
Insert Calendar into ListInserts an existing calendar into the user's calendar list.
Update Calendar List EntryUpdates an existing entry on the user\'s calendar list.
Delete CalendarDeletes a secondary calendar.
Update CalendarUpdates metadata for a calendar.
Clear CalendarClears a primary calendar.
Create EventCreates an event on a google calendar, needing rfc3339 utc start/end times (end after start) and write access to the calendar.
Delete eventDeletes a specified event by `event id` from a google calendar (`calendar id`); this action is idempotent and raises a 404 error if the event is not found.
Create a calendarCreates a new, empty google calendar with the specified title (summary).
Get Event InstancesReturns instances of the specified recurring event.
List EventsReturns events on the specified calendar.
Move EventMoves an event to another calendar, i.
Watch EventsWatch for changes to events resources.
Find eventFinds events in a specified google calendar using text query, time ranges (event start/end, last modification), and event types; ensure `timemin` is not chronologically after `timemax` if both are provided.
Find free slotsFinds free/busy time slots in google calendars for specified calendars within a defined time range (defaults to the current day utc if `time min`/`time max` are omitted), enhancing busy intervals with event details; `time min` must precede `time max` if both are provided.
Query Free/Busy InformationReturns free/busy information for a set of calendars.
Get Google CalendarRetrieves a specific google calendar, identified by `calendar id`, to which the authenticated user has access.
Get current date and timeGets the current date and time, allowing for a specific timezone offset.
List ACL RulesRetrieves the list of access control rules (acls) for a specified calendar, providing the necessary 'rule id' values required for updating specific acl rules.
List Google CalendarsRetrieves calendars from the user's google calendar list, with options for pagination and filtering.
Patch CalendarPartially updates (patches) an existing google calendar, modifying only the fields provided; `summary` is mandatory and cannot be an empty string, and an empty string for `description` or `location` clears them.
Patch EventUpdates specified fields of an existing event in a google calendar using patch semantics (array fields like `attendees` are fully replaced if provided); ensure the `calendar id` and `event id` are valid and the user has write access to the calendar.
Quick Add EventParses natural language text to quickly create a basic google calendar event with its title, date, and time, suitable for simple scheduling; does not support direct attendee addition or recurring events, and `calendar id` must be valid if not 'primary'.
Remove attendee from eventRemoves an attendee from a specified event in a google calendar; the calendar and event must exist.
List SettingsReturns all user settings for the authenticated user.
Watch SettingsWatch for changes to settings resources.
Sync EventsSynchronizes google calendar events, performing a full sync if no `sync token` is provided or if a 410 gone error (due to an expired token) necessitates it, otherwise performs an incremental sync for events changed since the `sync token` was issued.
Update ACL RuleUpdates an access control rule for the specified calendar.
Update Google eventUpdates an existing event by `event id` in a google calendar; this is a full put replacement, so provide all desired fields as unspecified ones may be cleared or reset.

Way Forward

With Google Calendar connected, Hermes can now act on your behalf whenever it detects a relevant task or you ask it to.

From here, you can extend Hermes further:

  • Connect more apps: Calendar, Slack, Notion, Linear, and hundreds of others are available through the same Composio Connect setup. Each new integration compounds what Hermes can do for you.
  • Build workflows across tools: Once multiple apps are connected, Hermes can chain actions together — turn an email into a calendar invite, a Slack message into a Linear ticket, or a meeting note into a follow-up draft.
  • Let it learn your patterns: The more you use Hermes, the better it gets at anticipating how you'd handle recurring tasks. Give it feedback on drafts and decisions, and it will adapt.

If you run into trouble or want to share what you've built, join the community or check out the Docs for deeper configuration options.

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FAQ

What are the differences in Tool Router MCP and Google Calendar MCP?

With a standalone Google Calendar MCP server, the agents and LLMs can only access a fixed set of Google Calendar tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Google Calendar and many other apps based on the task at hand, all through a single MCP endpoint.

Can I use Tool Router MCP with Hermes?

Yes, you can. Hermes fully supports MCP integration. You get structured tool calling, message history handling, and model orchestration while Tool Router takes care of discovering and serving the right Google Calendar tools.

Can I manage the permissions and scopes for Google Calendar while using Tool Router?

Yes, absolutely. You can configure which Google Calendar scopes and actions are allowed when connecting your account to Composio. You can also bring your own OAuth credentials or API configuration so you keep full control over what the agent can do.

How safe is my data with Composio Tool Router?

All sensitive data such as tokens, keys, and configuration is fully encrypted at rest and in transit. Composio is SOC 2 Type 2 compliant and follows strict security practices so your Google Calendar data and credentials are handled as safely as possible.

Used by agents from

Context
Letta
glean
HubSpot
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Context
Letta
glean
HubSpot
Agent.ai
Altera
DataStax
Entelligence
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Context
Letta
glean
HubSpot
Agent.ai
Altera
DataStax
Entelligence
Rolai

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