Astrocal

Name: Astrocal
Author: astrocal

@astrocalMCP server · External

AI-native scheduling: check availability, book meetings, cancel and reschedule via MCP

Calendarv0.1.6MITTypeScript

Freeno charge per call

One address for any MCP client. You sign in at api.astrocal.dev once, after adding it.

What it does

Reads
Writes
High impact

At most: moves money, runs code or commands, deletes data, or sends messages for you.

What it costs

Free

Odel charges nothing per call. The publisher may charge for its own service.

What it asks for at sign-in

Access to	Read	Change
Event types
Availability
Bookings
Waitlist

From the sign-in at api.astrocal.dev, as the endpoint publishes it. You approve it there.

Tools

None listed · checked 12 Oct 2026

Odel could not list its tools without signing in.

Try it in the Inspector

README4 min readView on GitHub

@astrocal/mcp-server

Give your AI agents the power to schedule meetings. The official Model Context Protocol server for Astrocal — the API-first scheduling platform built for developers and AI agents.

Works with Claude Desktop, Cursor, Windsurf, and any MCP-compatible client. Your AI assistant can check availability, book meetings, cancel, reschedule, and manage waitlists — all through natural conversation.

Get your API key | Documentation | API Reference

Why Astrocal for AI Agents?

Purpose-built for AI — Not a Calendly bolt-on. Astrocal's scheduling API was designed from day one for programmatic and AI-agent access.
8 tools, zero config — Check availability, book, cancel, reschedule, list event types, manage waitlists. Everything an agent needs.
Calendar sync built in — Connects to Google Calendar, Microsoft 365, and CalDAV. Your agent books against real availability.
Payments included — Stripe Connect integration means your agent can book paid consultations, not just free meetings.
Sandbox mode — Test with ac_test_* keys. No emails sent, no calendar events created, no charges made.

Quick Start

Claude Desktop

Add to your claude_desktop_config.json:

json

{
  "mcpServers": {
    "astrocal": {
      "command": "npx",
      "args": ["-y", "@astrocal/mcp-server"],
      "env": {
        "ASTROCAL_API_KEY": "ac_live_xxxxxxxxxxxxx"
      }
    }
  }
}

Restart Claude Desktop and the scheduling tools will be available immediately.

Other MCP Clients

Install globally:

bash

npm install -g @astrocal/mcp-server

Run:

bash

ASTROCAL_API_KEY=ac_live_xxx astrocal-mcp

Environment Variables

Variable	Required	Description
`ASTROCAL_API_KEY`	Yes	Your Astrocal API key (get one free)
`ASTROCAL_API_URL`	No	API base URL (default: `https://api.astrocal.dev`)
`ASTROCAL_DEFAULT_EVENT_TYPE_ID`	No	Default event type ID — your agent won't need to specify it on every call

Available Tools

`check_availability`

Check available time slots for booking.

event_type_id (string, optional) — Event type to check. Optional if ASTROCAL_DEFAULT_EVENT_TYPE_ID is set.
start_date (string, required) — Start date in ISO 8601 format (e.g., 2026-03-15)
end_date (string, required) — End date in ISO 8601 format (e.g., 2026-03-22)
timezone (string, optional) — IANA timezone (e.g., America/New_York). Defaults to UTC.

`create_booking`

Book a meeting at a specific time.

event_type_id (string, optional) — Event type to book. Optional if default is set.
start_time (string, required) — ISO 8601 datetime (e.g., 2026-03-15T14:00:00Z)
invitee_name (string, required) — Full name of the person booking
invitee_email (string, required) — Email address for calendar invitation
invitee_timezone (string, optional) — IANA timezone. Defaults to UTC.
notes (string, optional) — Meeting notes (max 1000 characters)

`cancel_booking`

Cancel an existing booking. The invitee receives a cancellation email automatically.

booking_id (string, required) — ID of the booking to cancel
reason (string, optional) — Cancellation reason (max 500 characters)

`reschedule_booking`

Reschedule a booking to a new time. Check availability first.

booking_id (string, required) — ID of the booking to reschedule
new_start_time (string, required) — New time in ISO 8601 format
reason (string, optional) — Reason for rescheduling (max 500 characters)

`list_bookings`

List bookings with optional filters.

status (string, optional) — Filter: confirmed, cancelled, or pending_payment
limit (number, optional) — Max results (default: 10, max: 100)
event_type_id (string, optional) — Filter by event type

`list_event_types`

List available event types that can be booked. No input required.

`join_waitlist`

Join the waitlist when all slots are full.

event_type_id (string, required) — Event type to join the waitlist for
name (string, required) — Full name
email (string, required) — Email address
preferred_times (string, optional) — Preferred time ranges or notes

`check_waitlist`

Check your position on a waitlist.

waitlist_entry_id (string, required) — Waitlist entry ID returned from join_waitlist

Example Conversation

User: "What meetings can I book?"

Agent: calls list_event_types — "You have two event types: a 30-minute consultation (free) and a 1-hour strategy session ($50)."

User: "Check if next Tuesday at 2pm is free for a consultation"

Agent: calls check_availability — "Tuesday at 2pm is available."

User: "Book it for jane@example.com"

Agent: calls create_booking — "Done! Meeting confirmed for Tuesday, March 17 at 2:00 PM UTC with Jane. A calendar invitation has been sent."

User: "Actually, move it to 3pm"

Agent: calls reschedule_booking — "Rescheduled to 3:00 PM. Jane has been notified."

Part of the Astrocal Platform

This MCP server is one of several ways to integrate with Astrocal:

REST API — Full scheduling API with OpenAPI 3.1 spec
React SDK (@astrocal/react) — Typed hooks, provider, and booking widget for React apps
Embeddable Widget (@astrocal/widget) — Drop-in booking UI for any website
Dashboard — Manage event types, bookings, team members, and billing
Webhooks — Real-time notifications for booking events