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carddav-mcp - Address Book Operations over CardDAV for Agents

Local stdio MCP server (TypeScript, MIT) - carddav-mcp reads and writes address books over CardDAV from an MCP client: contacts, groups and contact photos on any server that implements RFC 6352 - Radicale, Baikal, Nextcloud, SOGo, Fastmail, iCloud and hosted providers generally. Part of the ni-c suite alongside imap-mcp, smtp-mcp and caldav-mcp.

Server type: Local (stdio, TypeScript)
Auth: CardDAV account credentials; no vendor API
Install: npx @ni-c/carddav-mcp
Tools: 17 (10 read, 7 write); CARDDAV_READ_ONLY=true unregisters the write tools
Pricing: Free software
Category: Productivity
Built by: ni-c (github.com/ni-c/carddav-mcp)

Why This Matters for Operators

Contact data has a long tail of legacy detail - a vCard property a phone wrote in 2014, a group defined in the Apple convention that the other convention cannot see - and naive contact tools destroy exactly that. carddav-mcp's writes are read-modify-write over the parsed card guarded with If-Match, never a document rebuilt from the fields the server models, so unknown properties, photos and parameters survive every edit.

Both group conventions are read (vCard 4 KIND:group with MEMBER, and Apple's X-ADDRESSBOOKSERVER-KIND), and a written group follows whichever convention the address book already uses - because a group in the other convention is invisible in the client the person is looking at.

Tools & Capabilities

Group What the agent does
Contact operations Read, create, update and delete contacts with full property preservation
Groups Read both group conventions; write in the address book's existing convention
Photos Read and write contact photos
Search Single addressbook-query per search with local re-checking of results
Safety controls CARDDAV_READ_ONLY unregisters write tools; CARDDAV_ALLOW_TOOLS=essential narrows to a curated six

Installation

npx @ni-c/carddav-mcp

Configuration

{
  "mcpServers": {
    "carddav": {
      "command": "npx",
      "args": ["@ni-c/carddav-mcp"],
      "env": {
        "CARDDAV_URL": "https://dav.example.com",
        "CARDDAV_USERNAME": "ops@example.com"
      }
    }
  }
}

Set CARDDAV_READ_ONLY=true for a strictly read-only surface, or CARDDAV_ALLOW_TOOLS=essential to narrow to a curated six-tool set.

Business Relevance

  • Sales teams let the agent maintain CRM-adjacent contact books on self-hosted servers.
  • Teams on Nextcloud or Fastmail get agent contact management without platform lock-in.
  • Privacy-conscious operators keep contact data on their own CardDAV server, not a vendor CRM.
  • Developers complete the ni-c stack: imap-mcp (mail), smtp-mcp (send), caldav-mcp (calendar), carddav-mcp (contacts).

Integration with CorpusIQ

CorpusIQ holds the revenue relationships; carddav-mcp holds the people. A composed workflow: the agent identifies top accounts in CorpusIQ's Stripe data, then updates the stakeholder contacts and groups in the team's CardDAV address book so every touchpoint has current details.

Limitations

  • Brand new listing (issue #3966, Sep 6, 2026); repo and package are days old (0 stars).
  • Requires a CardDAV-compatible server; proprietary contact stores are out of scope.
  • Write safety depends on the server honoring If-Match.

See Also

Contact Terms Privacy Pricing