Getting started

Requirements

• Node.js ≥ 22
• A CalDAV account — Nextcloud, Radicale, Baikal, SOGo, Fastmail, mailbox.org, iCloud, or anything else that speaks the standard
• Its URL, your username, and a password. There is no token to obtain and no scopes to grant; see Configuration, and use an app-specific password where the provider offers one

Run it

CALDAV_URL=https://dav.example.net \
CALDAV_USERNAME=you \
CALDAV_PASSWORD=your-app-password \
  npx -y @ni-c/caldav-mcp

Nothing is written on startup, and nothing is read either: the server registers its tools and waits. The first tool call is what walks from that URL to the principal and the calendar home set.

Two more worth setting straight away:

CALDAV_TIMEZONE=Europe/Berlin   # for a time somebody types without an offset
CALDAV_READ_ONLY=true           # registers the read tools and nothing else

CALDAV_TIMEZONE defaults to UTC, which is rarely what a person means by "three o'clock". CALDAV_READ_ONLY is worth trying first: it is the cheapest way to see what the server does before letting it change anything.

Without credentials the server still starts and still lists its tools; every call then fails with setup instructions rather than reaching the network. That is deliberate — a client that probes the tool list at launch should not need a configured account to see one.

Next: connect a client, or read the tool reference.