dav-mcp

dav-mcp

An MCP server for CalDAV and CardDAV. Exposes calendar and contact management as tools callable by LLM clients (Claude Desktop, Cursor, etc.).

Transport: stdio. No HTTP server, no daemon — the client spawns the process and communicates over stdin/stdout per the MCP spec.

Requirements

• Go 1.22+
• A CalDAV / CardDAV server (Nextcloud, Radicale, iCloud, Fastmail, …)

Build

make          # tidy deps + build → bin/dav-mcp
make test     # run tests with race detector + coverage
make check    # fmt + vet + test

Configuration

Single account

Set three environment variables and the server auto-connects on the first tool call — no explicit dav_connect needed.

Variable	Required	Description
DAV_URL	yes	Base URL of the DAV server
DAV_USERNAME	yes	Username for Basic Auth
DAV_PASSWORD	yes	Password for Basic Auth
DAV_DEBUG	no	Set to 1 for verbose HTTP logging

Multiple accounts (DAV_ACCOUNTS)

Set DAV_ACCOUNTS to a JSON array of account objects. When present, it takes priority over DAV_URL / DAV_USERNAME / DAV_PASSWORD.

export DAV_ACCOUNTS='[
  {"name": "personal", "url": "https://cloud.example.com",  "username": "alice", "password": "s3cr3t"},
  {"name": "work",     "url": "https://dav.corp.example",   "username": "alice@corp", "password": "w0rkp@ss"}
]'

Field	Required	Description
name	no	Account label used in tool calls; defaults to account1, account2, …
url	yes	Base URL of the DAV server
username	no	Username for Basic Auth
password	no	Password for Basic Auth

All accounts are connected in parallel at startup. Pass "account": "work" to any tool to target a specific account. Omitting account selects the first configured account.

MCP Client Setup

Single account — Claude Desktop (claude_desktop_config.json)

{
  "mcpServers": {
    "dav": {
      "command": "/path/to/bin/dav-mcp",
      "env": {
        "DAV_URL": "https://dav.example.com",
        "DAV_USERNAME": "alice",
        "DAV_PASSWORD": "secret"
      }
    }
  }
}

Multiple accounts — Claude Desktop

{
  "mcpServers": {
    "dav": {
      "command": "/path/to/bin/dav-mcp",
      "env": {
        "DAV_ACCOUNTS": "[{\"name\":\"personal\",\"url\":\"https://cloud.example.com\",\"username\":\"alice\",\"password\":\"s3cr3t\"},{\"name\":\"work\",\"url\":\"https://dav.corp.example\",\"username\":\"alice@corp\",\"password\":\"w0rkp@ss\"}]"
      }
    }
  }
}

Cursor (~/.cursor/mcp.json)

{
  "mcpServers": {
    "dav": {
      "command": "/path/to/bin/dav-mcp",
      "env": {
        "DAV_ACCOUNTS": "[{\"name\":\"personal\",\"url\":\"https://cloud.example.com\",\"username\":\"alice\",\"password\":\"s3cr3t\"},{\"name\":\"work\",\"url\":\"https://dav.corp.example\",\"username\":\"alice@corp\",\"password\":\"w0rkp@ss\"}]"
      }
    }
  }
}

Tools

Every tool accepts an optional "account" parameter to target a specific configured account. When omitted, the first (primary) account is used.

Session

Tool	Description
dav_connect	Connect to a CalDAV/CardDAV server and discover calendars and address books
dav_reconnect	Reconnect one or all accounts from environment config

Calendar (CalDAV)

Tool	Description
calendar_calendar_list	List all discovered calendar collections
calendar_event_list	List events in a time range
calendar_event_create	Create a new event
calendar_event_create_recurring	Create a recurring event (RFC 5545 rrule, e.g. FREQ=WEEKLY;BYDAY=MO,WE)
calendar_event_update	Update an existing event by UID (only supplied fields are changed)
calendar_event_delete	Delete an event by UID

Tasks (CalDAV — VTODO)

Tool	Description
calendar_todo_list	List VTODO items; optionally filter by status (NEEDS-ACTION, IN-PROCESS, COMPLETED, CANCELLED)
calendar_todo_get	Get a single todo by UID
calendar_todo_create	Create a new todo (summary, due, priority, status)
calendar_todo_update	Update an existing todo by UID (only supplied fields are changed)
calendar_todo_delete	Delete a todo by UID

Journal (CalDAV — VJOURNAL)

Tool	Description
calendar_journal_list	List VJOURNAL entries; optionally filter by status (DRAFT, FINAL, CANCELLED)
calendar_journal_get	Get a single journal entry by UID
calendar_journal_create	Create a new journal entry (summary, description, date, status)
calendar_journal_update	Update an existing journal entry by UID (only supplied fields are changed)
calendar_journal_delete	Delete a journal entry by UID

Contacts (CardDAV)

Tool	Description
contacts_list	List all contacts in an address book
contacts_get	Get a single contact by UID
contacts_search	Search contacts by name, email, phone, or org
contacts_create	Create a new contact (vCard 4.0)
contacts_update	Update an existing contact (only supplied fields are changed)
contacts_delete	Delete a contact by UID

Server Capabilities

During connection, dav-mcp queries supported-calendar-component-set for each calendar collection. Tools that require a component type the server does not advertise return an explanatory message instead of attempting the operation:

VTODO is not supported by this CalDAV server.

Debugging

Enable verbose HTTP logging to stderr:

DAV_DEBUG=1 DAV_URL=https://dav.example.com DAV_USERNAME=alice DAV_PASSWORD=secret ./bin/dav-mcp

Project Layout

cmd/dav-mcp/      entry point
internal/
  config/         env-based configuration (DAV_URL / DAV_ACCOUNTS)
  dav/            WebDAV HTTP client (Propfind, Report, Put, Delete) + session store
  ical/           iCalendar builder and parser (VEVENT, VTODO, VJOURNAL)
  mcp/            MCP protocol (stdio transport, JSON-RPC 2.0)
  tools/          tool handlers (calendar, tasks, journal, contacts)
  vcard/          vCard 4.0 builder and parser

License

MIT