nextcloud-organizer-mcp

Let Claude run your Nextcloud tasks, calendar and notes.
A self-hosted MCP server for CalDAV tasks, events and the Notes app.

_{Real tool calls against a real Nextcloud · watch as video}

Ask in plain language, and your own Nextcloud changes. No copy-paste, no third-party calendar service: the data stays on your server and the tools talk to it over standard CalDAV and the Notes REST API.

Community project, not affiliated with or endorsed by Nextcloud GmbH. Formerly nextcloud-task-mcp.

What you can say

What Claude wrote shows up in the normal Nextcloud apps, immediately:

Features

• Tasks (VTODO): priorities, tags, reminders, subtasks, recurrence with exception dates, four-state status, batch update/delete/move.
• Calendars and events (VEVENT): recurring events, attendees and RSVP, free/busy, sharing, ICS import/export, birthdays, batch operations, trash bin.
• Timeboxing: turn a task into a calendar block and keep both linked.
• Notes: create, search, append, replace a passage or a single Markdown section.
• Combined day agenda: events and due tasks together.
• Safe by default: OAuth 2.1 with a password consent page, https:// enforced for Nextcloud, clean error messages instead of stack traces.
• 51 tools in total, documented in the tool reference.

Compatibility

The server speaks standard Streamable HTTP MCP with OAuth 2.1 (Dynamic Client Registration + PKCE), so other clients may work. The OAuth redirect allow-list defaults to claude.ai and claude.com; other clients need MCP_OAUTH_ALLOWED_REDIRECT_DOMAINS set. Reports from other clients are welcome.

Quick start

Requires Python 3.10+ and a Nextcloud with the Calendar/Tasks and Notes apps.

uv tool install nextcloud-organizer-mcp   # or: pipx install nextcloud-organizer-mcp

Create an app password under Settings → Security → Devices & sessions (never your account password), then set:

export NEXTCLOUD_BASE_URL=https://cloud.example.com
export NEXTCLOUD_USERNAME=your-username
export NEXTCLOUD_APP_PASSWORD=your-app-password
export PUBLIC_BASE_URL=https://your-host.ts.net   # the URL clients use
export MCP_OAUTH_PASSWORD=a-long-random-password  # required unless local

nextcloud-organizer-mcp     # listens on 127.0.0.1:8000, path /mcp

From a checkout instead: uv sync && cp .env.example .env, edit .env, then uv run nextcloud-organizer-mcp. Every setting is documented in .env.example. NEXTCLOUD_BASE_URL must be https:// unless it points at a local address.

Then expose the server (the deployment guide uses Tailscale Funnel for TLS) and add it in Claude under Settings → Connectors → Add custom connector with the URL <PUBLIC_BASE_URL>/mcp. Leave Client ID and Secret blank and enter your MCP_OAUTH_PASSWORD on the consent page that opens. Details: Authentication.

How it works

Claude ── HTTPS + OAuth 2.1 ──► your server (this project) ── CalDAV / Notes API ──► Nextcloud

• One CalDAV connection is opened at startup and reused for every request.
• No tool or CalDAV logic runs until a request carries a valid access token.
• The server binds to a local HTTP port and does not handle TLS itself.
• Timestamps use MCP_DEFAULT_TIMEZONE (default Europe/Berlin); naive inputs are interpreted in it.

Documentation

• Deployment guide — Ubuntu LXC + Tailscale + systemd + Claude connector setup
• Authentication — OAuth model, consent page, local security patches
• Tool reference — all tools with parameters, examples and error messages
• Architecture — module layout, request flow, design decisions
• Contributing — dev setup, checks, branches (main released, dev active)
• Changelog · Security policy

License

MIT