Astrocal — Claude Code MCP server: what it does, how to install
Connects scheduling workflows to your AI assistant for slot checking, booking, and waitlists. Useful when an agent needs to handle meetings directly inside chat.
claude mcp add --transport http mcp-server https://api.astrocal.dev/mcpWhat Astrocal does
This MCP server hooks into the Astrocal platform, giving the model eight dedicated tools. The assistant can inspect open intervals across Google Calendar, Microsoft 365, or CalDAV. It books, reschedules, and cancels calls. Cancellations automatically email the invitee.
The toolset handles waitlist entries and supports paid appointments through Stripe Connect. Running it requires ASTROCAL_API_KEY. Defining ASTROCAL_DEFAULT_EVENT_TYPE_ID saves the model from needing an explicit event ID on every routine request.
Live keys immediately create calendar events and process charges. Test your prompts with ac_test_* keys first to avoid accidental emails or payment actions.
What it helps with
- Check open slots across Google Calendar, Microsoft 365, or CalDAV
- Book and reschedule appointments directly from chat
- Collect payments for sessions using Stripe Connect
- Place attendees on a waitlist when dates are fully booked
Example prompts for the agent
- Check if there are open slots for a consultation next week
- Book a meeting for [email protected] on March 17 at 14:00 UTC
- Reschedule booking book_123 to 15:00 UTC
How to install Astrocal
1Platform CLI: remote server
claude mcp add --transport http mcp-server https://api.astrocal.dev/mcp2Platform CLI
claude mcp add --env ASTROCAL_API_KEY=<ASTROCAL_API_KEY> --env ASTROCAL_API_URL=<ASTROCAL_API_URL> --env ASTROCAL_DEFAULT_EVENT_TYPE_ID=<ASTROCAL_DEFAULT_EVENT_TYPE_ID> --transport stdio astrocal -- npx -y @astrocal/mcp-serverReplace <…> with your own values
1Platform CLI: remote server
codex mcp add astrocal --url https://api.astrocal.dev/mcp2Platform CLI
codex mcp add astrocal --env ASTROCAL_API_KEY=<ASTROCAL_API_KEY> --env ASTROCAL_API_URL=<ASTROCAL_API_URL> --env ASTROCAL_DEFAULT_EVENT_TYPE_ID=<ASTROCAL_DEFAULT_EVENT_TYPE_ID> -- npx -y @astrocal/mcp-serverReplace <…> with your own values
Config file
{
"mcpServers": {
"astrocal": {
"url": "https://api.astrocal.dev/mcp"
}
}
}{
"mcpServers": {
"astrocal": {
"command": "npx",
"args": [
"-y",
"@astrocal/mcp-server"
],
"env": {
"ASTROCAL_API_KEY": "<ASTROCAL_API_KEY>",
"ASTROCAL_API_URL": "<ASTROCAL_API_URL>",
"ASTROCAL_DEFAULT_EVENT_TYPE_ID": "<ASTROCAL_DEFAULT_EVENT_TYPE_ID>"
}
}
}
}Replace <…> with your own values
Config file
{
"servers": {
"astrocal": {
"type": "http",
"url": "https://api.astrocal.dev/mcp"
}
}
}{
"servers": {
"astrocal": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"@astrocal/mcp-server"
],
"env": {
"ASTROCAL_API_KEY": "<ASTROCAL_API_KEY>",
"ASTROCAL_API_URL": "<ASTROCAL_API_URL>",
"ASTROCAL_DEFAULT_EVENT_TYPE_ID": "<ASTROCAL_DEFAULT_EVENT_TYPE_ID>"
}
}
}
}Replace <…> with your own values
1Platform CLI: remote server
gemini mcp add -t http astrocal https://api.astrocal.dev/mcp2Platform CLI
gemini mcp add -e ASTROCAL_API_KEY=<ASTROCAL_API_KEY> -e ASTROCAL_API_URL=<ASTROCAL_API_URL> -e ASTROCAL_DEFAULT_EVENT_TYPE_ID=<ASTROCAL_DEFAULT_EVENT_TYPE_ID> astrocal npx -y @astrocal/mcp-serverReplace <…> with your own values
Step by step, with commands for each platform: How to add an MCP server to Claude Code, Codex, Cursor, VS Code, Gemini CLI and more
Questions about Astrocal
How do I install Astrocal in Claude Code?
Run claude mcp add --transport http astrocal https://api.astrocal.dev/mcp for HTTP transport, or run `claude mcp add --env ASTROCAL_API_KEY=<ASTROCAL_API_KEY> --env ASTROCAL_API_URL=<ASTROCAL_API_URL> --env ASTROCAL_DEFAULT_EVENT_TYPE_ID=<ASTROCAL_DEFAULT_EVENT_TYPE_ID> --transport stdio astrocal -- npx -y @astrocal/mcp-server` to run it via stdio.
What does the Astrocal MCP server do?
It lets an AI assistant search calendar availability, reserve meeting slots, cancel or reschedule bookings, and track waitlist entries.
How can I safely test scheduling without notifying clients?
Use a key starting with ac_test_*. In sandbox mode, the server avoids creating real calendar events, sending emails, or processing Stripe charges.
