CalDAV MCP Server

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Expose CalDAV calendar operations as MCP tools for AI assistants.

How to install ↓ Compare GitHub source repository ↗

Category: Collaboration #29 of 55
Stars: ★ 103 Popular
Transport: stdio (local process)
Runtime: Node.js
Credentials: API key / credential required
License: MIT
Last commit: 26 days ago
Tools: 10

53FMRS · D

This server provides AI assistants with the ability to access CalDAV calendars and tasks via MCP. It is feature-rich but requires user-provided CalDAV credentials, posing some security risks.

Strongest · Maintenance 13/20 Weakest · Reliability 7/20

Reliability

7/20

Security and permissions

11/20

Maintenance

13/20

Documentation

12/20

Setup experience

10/20

Why each score

Reliability 7/20: The server manifest and README describe tools, but static review only provides README-generated tool list; no actual source code to verify implementation or tests. No test evidence provided, CI workflows not shown in provided content. Therefore, reliability capped at 12 due to static limitation, and deductions made for lack of verifiable test evidence and source.
Security and permissions 11/20: Credentials handled via environment variables, password marked as secret. However, no source code provided to inspect error handling or data minimization. Delete operations (delete event/todo) may lack confirmation, but UID parameters exist. No red lines detected, but lack of detailed source review for security practices results in moderate score.
Maintenance 13/20: Repository has MIT license, not archived, has semantic-release and CI badges. Release workflow present. However, no commit history or version details provided. Maintenance activity inferred from signals but not fully verified.
Documentation 12/20: README provides setup example, tool parameter descriptions, and feature list. It lacks in-depth troubleshooting, limitations, and detailed execution examples. Documentation usable but evidence limited to README and generated docs.
Setup experience 10/20: Installation via npm and npx, with client configuration example. Environment variables documented. However, no execution steps or platform compatibility tests provided. Instructions simple, but complexity may vary with CalDAV server.

Static review · not runListed 2026-08-07

Read the FMRS scoring method →

Fit and risk

What it can accessUses the network

Best for

AI assistants that need calendar integration
Users with CalDAV-compatible servers
Scenarios requiring task management

Not for

Direct Google Calendar integration (non-CalDAV)
Users who need complex calendar permission management
Users with high security concerns who don't trust third-party MCP servers

Required permissions

Requires access to CalDAV server credentials (username and password)
Requires read and write capabilities for calendars and tasks

Risks and side effects

Credential leakage: password may be stored in configuration
If the MCP client is maliciously controlled, calendar data could be modified or deleted

Setup

Before you start

Runtime：Node.js

CALDAV_BASE_URL required Base URL of your CalDAV server, e.g. https://caldav.example.com, provided by your calendar service.

CALDAV_USERNAME required Username for CalDAV authentication, typically your calendar account name.

CALDAV_PASSWORD requiredsecret Password for CalDAV authentication; prefer an app-specific password from your calendar service and treat it as a secret.

Add the following configuration to your MCP client:

{
  "mcpServers": {
    "calendar": {
      "command": "npx",
      "args": ["caldav-mcp"],
      "env": {
        "CALDAV_BASE_URL": "<CalDAV server URL>",
        "CALDAV_USERNAME": "<CalDAV username>",
        "CALDAV_PASSWORD": "<CalDAV password>"
      }
    }
  }
}

claude_desktop_config.json

{
  "mcpServers": {
    "calendar": {
      "command": "npx",
      "args": ["caldav-mcp"],
      "env": {
        "CALDAV_BASE_URL": "<CalDAV server URL>",
        "CALDAV_USERNAME": "<CalDAV username>",
        "CALDAV_PASSWORD": "<CalDAV password>"
      }
    }
  }
}

Shown for Claude Desktop. Other clients may use a different file or key (VS Code uses "servers") — the configurator below converts it.

.vscode/mcp.json

{
  "servers": {
    "calendar": {
      "command": "npx",
      "args": [
        "caldav-mcp"
      ],
      "env": {
        "CALDAV_BASE_URL": "<CalDAV server URL>",
        "CALDAV_USERNAME": "<CalDAV username>",
        "CALDAV_PASSWORD": "<CalDAV password>"
      }
    }
  }
}

Goes in your project's .vscode/mcp.json (VS Code uses a "servers" key).

Terminal

claude mcp add calendar -e 'CALDAV_BASE_URL=<CalDAV server URL>' -e 'CALDAV_USERNAME=<CalDAV username>' -e 'CALDAV_PASSWORD=<CalDAV password>' -- npx caldav-mcp

Run it in a terminal; replace any <…> placeholders with your own values first.

Generate and validate client config

Check that it works

After installing and setting the environment variables, the client's tool list should show the 10 tools including list-calendars, list-events and create-event. Calling list-calendars and getting calendar names and URLs back proves the CalDAV connection works.

Troubleshooting

Check if CALDAV_BASE_URL is correct and a valid CalDAV endpoint
Verify username and password are valid
Ensure network can reach the CalDAV server

Things to try

Once connected, you can ask your AI assistant things like:

List all my calendars on the CalDAV server
Show me all events in my calendar from next Monday to Friday
Create an event in my main calendar for a meeting on Friday at 2pm in meeting room A
List all my open tasks that are due today

Tools 10

list-calendars read-only

List all calendars returning both name and URL.

list-events read-only

List all events between start and end date in the specified calendar.

create-event writes

Create an event in the specified calendar.

update-event writes

Update an existing event.

delete-event destructive

Delete an event by UID.

list-todos read-only

List tasks (VTODOs) with optional status and date filters.

create-todo writes

Create a task.

update-todo writes

Update an existing task.

Show 2 more tools

complete-todo writes

Mark a task as completed.

delete-todo destructive

Delete a task.

Use cases

AI assistants can query and manipulate calendar events

Create and manage tasks/to-dos

Integrate with CalDAV servers to automate scheduling

Supported clients

Claude Desktop

Listed from the project's documentation, not tested by this site.

Overview

CalDAV MCP Server is a Model Context Protocol (MCP) server that exposes calendar operations (such as listing, creating, updating, and deleting events) as tools for AI assistants. It supports CalDAV servers, allowing AI assistants to manage calendar events and tasks (VTODO).

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Source revision 725de72d9dc2 Data synced 2026-10-12 Read the FMRS scoring method