AddEvent MCP server

Read AddEvent calendars, events, RSVPs and subscribers; create and update calendars and events. Hosted by usefulapi: connect it to Claude, ChatGPT, Cursor or any MCP client.

Connect AddEvent50 free tool calls a month

What can I ask?

Turn on the AddEvent connector, then ask in plain words. The AI picks the tools.

Which events do I have scheduled next month?
List all the calendars in my account with their titles.
Who has RSVP'd so far to my open house event, and what did they answer?
Show the dates and times of the open house events in my account.

What you can do with AddEvent in Claude and ChatGPT

For event organizers and marketers who publish events and calendars with AddEvent.

List upcoming events and their dates

Searches events by calendar, text or date and shows title, start and end, timezone, location and RSVP settings. One event can be opened in full.

See who has RSVP'd to an event

Lists RSVP attendees for a calendar or event, filtered by response (going, maybe, not going), with their email and form answers.

Check our calendars and their subscribers

Lists calendars with timezone and counts of events and subscribers, opens one calendar, and lists the people subscribed to the calendars.

Create or update an event

Creates an event on a calendar with a timezone, RSVP form and landing page template, or changes fields of an existing event. Changes go live on its landing page.

Changes data

Create or update a calendar

Creates a new calendar with a title, or changes the title, description or timezone of an existing one. Changes show on its landing page.

Changes data

Add or update an RSVP attendee

Adds one RSVP attendee to an event by email, or changes an attendee's email, response or form answers.

Changes data

How do I connect AddEvent?

Before you connect

The login page asks for your AddEvent API key.

Find it in the AddEvent dashboard under Account settings. API access needs a paid AddEvent plan. The key gives full access to your account's calendars and events; it is used only to call the AddEvent API on your behalf and is never shown to anyone.

Claude claude.ai · Desktop

Open Customize → Connectors, then click + Add → Add custom connector.
Enter the name AddEvent and this URL, then click Add:
https://addevent.usefulapi.io/mcp
Claude opens the login page: enter your AddEvent API key.
In a chat, click + → Connectors and turn on AddEvent.

Team and Enterprise: an Owner adds the connector for the organization first.

ChatGPT chatgpt.com

Open Plugins, click +, then Add custom MCP server.
Enter the name AddEvent and this URL, choose OAuth as the authentication, confirm the warning and create it:
https://addevent.usefulapi.io/mcp
ChatGPT opens the login page: enter your AddEvent API key.
In Plugins, install AddEvent, then choose it in a chat.

No Add custom MCP server option? It depends on your account or workspace settings: see OpenAI's guide.

Claude Code

Run this command, then run /mcp in Claude Code to log in:

claude mcp add --transport http addevent https://addevent.usefulapi.io/mcp

Cursor

Add to Cursor or add this to ~/.cursor/mcp.json:

{
  "mcpServers": {
    "addevent": {
      "url": "https://addevent.usefulapi.io/mcp"
    }
  }
}

VS Code

Add to VS Code or add this to .vscode/mcp.json:

{
  "servers": {
    "addevent": {
      "type": "http",
      "url": "https://addevent.usefulapi.io/mcp"
    }
  }
}

Codex

Run these commands. The second one opens the login page:

codex mcp add addevent --url https://addevent.usefulapi.io/mcp

codex mcp login addevent

Other clients

Windsurf, Cline, Zed and other MCP clients: add this URL as a remote MCP server (Streamable HTTP). The client then opens the login page in your browser.

https://addevent.usefulapi.io/mcp

Add only the URL. Do not add an Authorization header or an API key to the client config. The server signs you in with OAuth: the login page asks for your AddEvent API key. If the config has such a header, remove it: some clients then send that header instead of the login token, and every call fails with 401.

Pricing

Plan	Price	Limit
Free	$0	50 tool calls / month
Proper account	$9/mo · $90/yr	10,000 tool calls / month
Pro+per account	$39/mo · $390/yr	100,000 tool calls / month

Each paid plan covers this AddEvent server only. Ask your AI to run addevent_upgrade and choose Pro or Pro+, billed monthly or yearly (it returns a Stripe Checkout link). If you already have Pro, ask to change it to Pro+. The change requires your confirmation, keeps your billing interval and charges the price difference for the rest of the period immediately. Cancel any time with addevent_cancel_subscription: your paid plan continues to the end of the paid period, with no refund for the current period, and asking to resume the same plan with addevent_upgrade before then undoes the cancel. Or write to support@usefulapi.io.

Tools 22

Show all 22 tools (the AI picks them for you)

Read only · 12

List calendarsaddevent_list_calendars
List the account's calendars (newest first by default) with id, title, timezone, whether it is the default calendar, landing-page links and counts of events and subscribers.
Get calendaraddevent_get_calendar
One calendar by id: title, timezone, week start, template ids, subscriber and event counts, links, custom data.
List eventsaddevent_list_events
Search the account's events (newest created first; by start time when a date filter is used): title, start/end, timezone, location, RSVP settings and stats, landing-page links. Filter by calendar, event ids, text, date window or a custom_data pair.
Get eventaddevent_get_event
One event by id (evt-...): all fields incl. description, organizer, reminder, recurring rule, RSVP settings and stats, custom data and share links.
List RSVP attendeesaddevent_list_rsvp_attendees
List RSVP attendees (personal data: e-mail addresses and the answers they gave on the RSVP form). Filter by calendar, event or response (going/maybe/not-going). Paged, 20 at most per page: read only what the task needs. IP address and coordinates are removed from the reply.
Get RSVP attendeeaddevent_get_rsvp_attendee
One RSVP attendee by id (personal data: e-mail and form answers; IP address and coordinates removed).
List calendar subscribersaddevent_list_calendar_subscribers
List people subscribed to the account's calendars (personal data: the form answers they gave, such as name and e-mail; calendar app type, sync status). Paged, 20 at most per page. IP address and coordinates are removed.
Get calendar subscriberaddevent_get_calendar_subscriber
One calendar subscriber by id (personal data; IP address and coordinates removed).
List RSVP formsaddevent_list_rsvp_forms
The account's RSVP forms (id, name), newest first. Use the id as rsvp_form_id on an event.
List event landing page templatesaddevent_list_event_templates
The account's event landing page templates (id, name), newest first. Use the id as landing_page_template_id on an event.
List calendar templatesaddevent_list_calendar_templates
The account's calendar landing page templates or embeddable calendar templates (id, name), newest first. Use the id as landing_page_template_id / embeddable_calendar_template_id on a calendar.
List timezonesaddevent_list_timezones
Timezone names AddEvent supports (use them as the timezone of events and calendars), with current UTC offset. Optional text filter on the name.

Changes data · 6

Create calendaraddevent_create_calendar
WRITE: creates a new calendar in the AddEvent account (a new, empty calendar; nothing existing is changed and nobody is notified). Needs a title.
Update calendaraddevent_update_calendar
WRITE: changes fields of an existing calendar (only the fields you pass; the rest stay). Title, description and timezone changes show on its landing page and can reach people who subscribe to the calendar feed. Not reversible by this server (no previous values are kept), so read the calendar first.
Create eventaddevent_create_event
WRITE: creates a new event on a calendar (the account's default calendar if calendar_id is omitted). Creates a public event landing page and share links; it does not e-mail anyone, though people subscribed to that calendar's feed will see the event on their next sync. Needs title and datetime_start.
Update eventaddevent_update_event
WRITE: changes fields of an existing event (only the fields you pass; the rest stay). The change goes live on its landing page and share links, and people who subscribed to the calendar or added the event with a live link are updated on their next calendar sync, so a time or location change can notify real people. No previous values are kept: read the event first.
Create RSVP attendeeaddevent_create_rsvp_attendee
WRITE: adds ONE RSVP attendee (one e-mail address, personal data) to an event. This server never asks AddEvent to send the confirmation or organizer notification e-mails, but the event's own reminder and follow-up e-mails (if the event has them) will later go to this address, so only add someone who really RSVP'd. The e-mail must be unique per event.
Update RSVP attendeeaddevent_update_rsvp_attendee
WRITE: changes ONE RSVP attendee (email, response or form answers; only the fields you pass). The event's reminder and update e-mails go to the e-mail address stored here, so changing it redirects those e-mails to that person. This server never triggers the confirmation or organizer notification e-mails.

Your usefulapi plan · 4

Usage status (free-tier meter)addevent_usage_status
Report the caller's current usage: the plan, calls used this month, the limit of the plan (the free monthly cap or the Pro fair use limit), remaining, and whether the limit is reached. Read-only; does not count against the meter.
Request a missing featureaddevent_request_feature
Tell usefulapi that the user needs something the AddEvent tools cannot do yet (a missing tool, field or filter). Call it only when the user asks for something none of the tools can do, and tell the user that you send the request. Do not call it for errors or for normal requests. Do not include personal data, credentials or customer records. Stored with the product name and the client type (for example Claude or Cursor), without the user's account. At most 5 requests per day. Does not count against the meter.
Upgrade to Pro or Pro+addevent_upgrade
Get a paid plan for AddEvent (the free tier caps monthly usage). Pro: 10,000 tool calls a month, for normal use — plan "monthly" ($9/month) or "yearly" ($90/year, 2 months free). Pro+: 100,000 tool calls a month, for automations and heavy use — plan "plus" ($39/month) or "plus_yearly" ($390/year). Without a plan it returns both Pro and Pro+, each with a payment link, for the user to choose; with a plan, one link. An existing Pro subscription changes to Pro+ in place: call without confirm first, as the reply states the exact charge for this account (the price difference for the rest of the period, or in a free Pro trial the full Pro+ price, as the trial ends); then call with confirm: true. Cancel any time: the plan then runs to the end of the paid period, so it also suits a one-time job. A link opens Stripe Checkout in the browser; after payment the account upgrades automatically. Does not count against the meter.
Cancel the Pro subscriptionaddevent_cancel_subscription
Cancel the caller's AddEvent Pro subscription at the end of the paid period (no refund for the current period; Pro continues until then, then the free tier applies). Requires confirm: true. Run addevent_upgrade later to undo the cancel before the period ends. Does not count against the meter.

FAQ

What can I do with AddEvent in Claude or ChatGPT?

List upcoming events and their dates. See who has RSVP'd to an event. Check our calendars and their subscribers. Create or update an event. Create or update a calendar. Add or update an RSVP attendee. See what you can do for the details.

Is this an official AddEvent product?

No. usefulapi is an independent service. It is not affiliated with or endorsed by AddEvent. The server calls the AddEvent API with your own AddEvent access, so it sees only the data that your account can see.

Can I connect AddEvent to Claude or ChatGPT?

Yes. In Claude, add this server's URL as a custom connector. In ChatGPT, add it as a custom MCP server in Plugins. Then log in once. Cursor, VS Code, Claude Code and Codex work too. See the setup steps.

What do I need to connect?

The login page asks for your AddEvent API key. See Before you connect for where to find it.

Do I put my AddEvent key or an Authorization header in the client config?

No. Add only the URL. Do not add an Authorization header or an API key to the client config. The server signs you in with OAuth: the login page asks for your AddEvent API key. If the config has such a header, remove it: some clients then send that header instead of the login token, and every call fails with 401.

How do you keep my AddEvent credentials?

The login stores them encrypted in the authorization grant of your connection. The server uses them to call the AddEvent API for you and to derive a private account id for usage metering. usefulapi does not show them on any page or in any reply. To stop all access, remove the connector and change or delete these credentials in AddEvent.

Can the AI change my AddEvent data?

Yes, if you approve it. 6 of the 18 AddEvent tools can create or change data. The other 12 are marked read-only. Most MCP clients ask you to approve a tool call before it runs.

What does it cost?

The Free plan gives 50 tool calls / month. Pro costs $9/mo or $90/yr, with 10,000 tool calls / month. Pro+ costs $39/mo or $390/yr, with 100,000 tool calls / month. Each subscription covers this AddEvent server only. Cancel any time: your paid plan then runs to the end of the paid period. Run addevent_usage_status to see how many calls you used.

How do I subscribe or cancel?

Ask the AI to run addevent_upgrade and choose Pro or Pro+, billed monthly or yearly: it returns a Stripe Checkout link. If you already have Pro, ask to change it to Pro+. After you confirm, your existing subscription changes in place, keeps its billing interval and charges the price difference for the rest of the period immediately. To cancel, run addevent_cancel_subscription. Your paid plan continues to the end of the paid period.

What if a AddEvent tool that I need is missing?

Tell the AI what you wanted to do. It can send the request with addevent_request_feature. We store the text with the server name, the type of AI client and the tool you tried, not with your account, and read every request when we plan new tools. You can send up to 5 requests per day.

Which AI clients can I use?

Any client that supports remote MCP servers (Streamable HTTP) with OAuth login: Claude (web and desktop), Claude Code, ChatGPT, Codex, Cursor, VS Code, Windsurf and others.

This is a Model Context Protocol endpoint — meant to be connected from an AI client, not opened in a browser. An invalid_token response at the URL is the auth gate working as designed; clients authenticate automatically.

Need a tool this server does not have, or a connection to another system? We build custom integrations and MCP servers.

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