CardDAV address books MCP server

carddav-mcp

<!-- badges: start -->

<!-- badges: end -->

A Model Context Protocol (MCP) server for CardDAV, the open contacts standard behind Nextcloud, Radicale, Baikal, SOGo, Fastmail, mailbox.org and iCloud.

Lets MCP clients like Claude Code, Claude Desktop or Codex work with your address book: find a person, read their card in full, add and correct contacts, keep groups, and fetch a contact photo — against your own server, with no vendor API in between.

Seventeen tools is the ceiling, not the floor: CARDDAVALLOWTOOLS=essential registers a curated six instead, and a model picks the right tool far more reliably from six than from seventeen — see choosing which tools load.

What makes it different

A listing stays cheap on a real address book. list_contacts asks the server for a dozen named properties rather than for whole cards, which is the difference between a few kilobytes and several megabytes once inline photos are involved. The entries it returns say partial out loud, because a card retrieved that way is missing everything nobody asked for — and the write path refuses to build on one, re-fetching every time.

Both group conventions, read and written. vCard 4 defines KIND:group with MEMBER. Apple got there first and shipped X-ADDRESSBOOKSERVER-KIND on top of vCard 3, and that is what Apple Contacts, Nextcloud and most of the installed base actually store. This server reads both and writes whichever the address book already uses — a group written in the other convention is not a compatibility footnote, it is invisible in the client the person is looking at.

Shortened. The full README is on GitHub.