Google Calendar Automation via Rube MCP

Automate Google Calendar workflows including event creation, scheduling, availability checks, attendee management, and calendar browsing through Composio's Google Calendar toolkit.

Toolkit docs: composio.dev/toolkits/googlecalendar

Prerequisites

• Rube MCP must be connected (RUBE_SEARCH_TOOLS available)

• Active Google Calendar connection via RUBE_MANAGE_CONNECTIONS with toolkit googlecalendar

• Always call RUBE_SEARCH_TOOLS first to get current tool schemas

Setup

Get Rube MCP: Add https://rube.app/mcp as an MCP server in your client configuration. No API keys needed — just add the endpoint and it works.

• Verify Rube MCP is available by confirming RUBE_SEARCH_TOOLS responds

• Call RUBE_MANAGE_CONNECTIONS with toolkit googlecalendar

• If connection is not ACTIVE, follow the returned auth link to complete Google OAuth

• Confirm connection status shows ACTIVE before running any workflows

Core Workflows

1. Create and Manage Events

When to use: User wants to create, update, or delete calendar events

Tool sequence:

• GOOGLECALENDAR_LIST_CALENDARS

• Identify target calendar ID [Prerequisite]

• GOOGLECALENDAR_GET_CURRENT_DATE_TIME

• Get current time with proper timezone [Optional]

• GOOGLECALENDAR_FIND_FREE_SLOTS

• Check availability before booking [Optional]

• GOOGLECALENDAR_CREATE_EVENT

• Create the event [Required]

• GOOGLECALENDAR_PATCH_EVENT

• Update specific fields of an existing event [Alternative]

• GOOGLECALENDAR_UPDATE_EVENT

• Full replacement update of an event [Alternative]

• GOOGLECALENDAR_DELETE_EVENT

• Delete an event [Optional]

Key parameters:

• calendar_id : Use 'primary' for main calendar, or specific calendar ID

• start_datetime : ISO 8601 format 'YYYY-MM-DDTHH:MM:SS' (NOT natural language)

• timezone : IANA timezone name (e.g., 'America/New_York', NOT 'EST' or 'PST')

• event_duration_hour : Hours (0+)

• event_duration_minutes : Minutes (0-59 only; NEVER use 60+)

• summary : Event title

• attendees : Array of email addresses (NOT names)

• location : Free-form text for event location

Pitfalls:

• start_datetime must be ISO 8601; natural language like 'tomorrow' is rejected

• event_duration_minutes max is 59; use event_duration_hour=1 instead of event_duration_minutes=60

• timezone must be IANA identifier; abbreviations like 'EST', 'PST' are NOT valid

• attendees only accepts email addresses, not names; resolve names first

• Google Meet link creation defaults to true; may fail on personal Gmail accounts (graceful fallback)

• Organizer is auto-added as attendee unless exclude_organizer=true

2. List and Search Events

When to use: User wants to find or browse events on their calendar

Tool sequence:

• GOOGLECALENDAR_LIST_CALENDARS

• Get available calendars [Prerequisite]

• GOOGLECALENDAR_FIND_EVENT

• Search by title/keyword with time bounds [Required]

• GOOGLECALENDAR_EVENTS_LIST

• List events in a time range [Alternative]

• GOOGLECALENDAR_EVENTS_INSTANCES

• List instances of a recurring event [Optional]

Key parameters:

• query / q : Free-text search (matches summary, description, location, attendees)

• timeMin : Lower bound (RFC3339 with timezone offset, e.g., '2024-01-01T00:00:00-08:00')

• timeMax : Upper bound (RFC3339 with timezone offset)

• singleEvents : true to expand recurring events into instances

• orderBy : 'startTime' (requires singleEvents=true) or 'updated'

• maxResults : Results per page (max 2500)

Pitfalls:

• Timezone warning: UTC timestamps (ending in 'Z') don't align with local dates; use local timezone offsets instead

• Example: '2026-01-19T00:00:00Z' covers 2026-01-18 4pm to 2026-01-19 4pm in PST

• Omitting timeMin /timeMax scans the full calendar and can be slow

• pageToken in response means more results; paginate until absent

• orderBy='startTime' requires singleEvents=true

3. Manage Attendees and Invitations

When to use: User wants to add, remove, or update event attendees

Tool sequence:

• GOOGLECALENDAR_FIND_EVENT or GOOGLECALENDAR_EVENTS_LIST

• Find the event [Prerequisite]

• GOOGLECALENDAR_PATCH_EVENT

• Add attendees (replaces entire attendees list) [Required]

• GOOGLECALENDAR_REMOVE_ATTENDEE

• Remove a specific attendee by email [Required]

Key parameters:

• event_id : Unique event identifier (opaque string, NOT the event title)

• attendees : Full list of attendee emails (PATCH replaces entire list)

• attendee_email : Email to remove

• send_updates : 'all', 'externalOnly', or 'none'

Pitfalls:

• event_id is a technical identifier, NOT the event title; always search first to get the ID

• PATCH_EVENT attendees field replaces the entire list; include existing attendees to avoid removing them

• Attendee names cannot be resolved; always use email addresses

• Use GMAIL_SEARCH_PEOPLE to resolve names to emails before managing attendees

4. Check Availability and Free/Busy Status

When to use: User wants to find available time slots or check busy periods

Tool sequence:

• GOOGLECALENDAR_LIST_CALENDARS

• Identify calendars to check [Prerequisite]

• GOOGLECALENDAR_GET_CURRENT_DATE_TIME

• Get current time with timezone [Optional]

• GOOGLECALENDAR_FIND_FREE_SLOTS

• Find free intervals across calendars [Required]

• GOOGLECALENDAR_FREE_BUSY_QUERY

• Get raw busy periods for computing gaps [Fallback]

• GOOGLECALENDAR_CREATE_EVENT

• Book a confirmed slot [Required]

Key parameters:

• items : List of calendar IDs to check (e.g., ['primary'])

• time_min /time_max : Query interval (defaults to current day if omitted)

• timezone : IANA timezone for interpreting naive timestamps

• calendarExpansionMax : Max calendars (1-50)

• groupExpansionMax : Max members per group (1-100)

Pitfalls:

• Maximum span ~90 days per Google Calendar freeBusy API limit

• Very long ranges or inaccessible calendars yield empty/invalid results

• Only calendars with at least freeBusyReader access are visible

• Free slots responses may normalize to UTC ('Z'); check offsets

• GOOGLECALENDAR_FREE_BUSY_QUERY requires RFC3339 timestamps with timezone

Common Patterns

ID Resolution

• Calendar name -> calendar_id: GOOGLECALENDAR_LIST_CALENDARS to enumerate all calendars

• Event title -> event_id: GOOGLECALENDAR_FIND_EVENT or GOOGLECALENDAR_EVENTS_LIST

• Attendee name -> email: GMAIL_SEARCH_PEOPLE

Timezone Handling

• Always use IANA timezone identifiers (e.g., 'America/Los_Angeles')

• Use GOOGLECALENDAR_GET_CURRENT_DATE_TIME to get current time in user's timezone

• When querying events for a local date, use timestamps with local offset, NOT UTC

• Example: '2026-01-19T00:00:00-08:00' for PST, NOT '2026-01-19T00:00:00Z'

Pagination

• GOOGLECALENDAR_EVENTS_LIST returns nextPageToken ; iterate until absent

• GOOGLECALENDAR_LIST_CALENDARS also paginates; use page_token

Known Pitfalls

• Natural language dates: NOT supported; all dates must be ISO 8601 or RFC3339

• Timezone mismatch: UTC timestamps don't align with local dates for filtering

• Duration limits: event_duration_minutes max 59; use hours for longer durations

• IANA timezones only: 'EST', 'PST', etc. are NOT valid; use 'America/New_York'

• Event IDs are opaque: Always search to get event_id; never guess or construct

• Attendees as emails: Names cannot be used; resolve with GMAIL_SEARCH_PEOPLE

• PATCH replaces attendees: Include all desired attendees in the array, not just new ones

• Conference limitations: Google Meet may fail on personal accounts (graceful fallback)

• Rate limits: High-volume searches can trigger 403/429; throttle between calls

Quick Reference

Task Tool Slug Key Params

List calendars GOOGLECALENDAR_LIST_CALENDARS

max_results

Create event GOOGLECALENDAR_CREATE_EVENT

start_datetime , timezone , summary

Update event GOOGLECALENDAR_PATCH_EVENT

calendar_id , event_id , fields to update

Delete event GOOGLECALENDAR_DELETE_EVENT

calendar_id , event_id

Search events GOOGLECALENDAR_FIND_EVENT

query , timeMin , timeMax

List events GOOGLECALENDAR_EVENTS_LIST

calendarId , timeMin , timeMax

Recurring instances GOOGLECALENDAR_EVENTS_INSTANCES

calendarId , eventId

Find free slots GOOGLECALENDAR_FIND_FREE_SLOTS

items , time_min , time_max , timezone

Free/busy query GOOGLECALENDAR_FREE_BUSY_QUERY

timeMin , timeMax , items

Remove attendee GOOGLECALENDAR_REMOVE_ATTENDEE

event_id , attendee_email

Get current time GOOGLECALENDAR_GET_CURRENT_DATE_TIME

timezone

Get calendar GOOGLECALENDAR_GET_CALENDAR

calendar_id

Powered by Composio