Ox MCP

What Rheopyrin/ox-mcp MCP server does

The Rheopyrin/ox-mcp MCP server exposes email, calendar, contact, and scheduling operations through MCP. It is designed for Open-Xchange deployments and other services that implement the relevant standards. A configuration can contain multiple named accounts, and each tool can target a specific account through its optional server argument.

Email capabilities include listing folders, reading and searching messages, sending or replying to mail, archiving, marking spam, and managing drafts and folders when the corresponding write features are enabled. Calendar support covers event listing and creation or changes, plus accepting, declining, or tentatively responding to invitations. Contact tools enumerate address books or search contacts by fields such as name, email, phone, and organization. The free/busy operation can check other people's availability.

How it works

The server groups configuration into independent mail, calDav, and cardDav sections. Each section has its own host, login, authentication settings, and feature controls, so deployments with protocol-specific credentials can use different app passwords. The mail section defaults to the Open-Xchange HTTP API. Setting its transport to imap switches mail access to direct IMAP and SMTP endpoints for generic standards-based hosts.

Rheopyrin/ox-mcp MCP server enables read tools by default and disables write tools by default. Tools only appear when their group is configured and the relevant feature is enabled. Environment variables take precedence over configuration-file values, with support for global and account-specific feature flags.

Search behavior depends on the mail transport. Searches through the Open-Xchange API match subjects and addresses of recent messages, while imap supports full-text search. Spam and archive actions locate folders using IMAP special-use attributes with name-based fallbacks.

Setup and configuration

Run the package with npx -y @rheopyrin/ox-mcp. Without a custom path, the first run creates ~/.ox-mcp/config.json with restrictive permissions and read features enabled. Use --config <file> or OX_MCP_CONFIG to load another configuration file; an override file must already exist.

The documented environment variables include OX_MCP_MAIL_SERVER, OX_MCP_MAIL_USER, and OX_MCP_MAIL_APP_PASSWORD for mail, along with corresponding OX_MCP_CALDAV_* and OX_MCP_CARDDAV_* variables for calendar and contacts. Authentication can use an email plus app password or OAuth2/OIDC. A configured section may be omitted when that protocol is not needed.

Rheopyrin/ox-mcp MCP server can be added to Claude Desktop using a stdio entry whose command is npx and whose arguments are -y and @rheopyrin/ox-mcp.

Tools and capabilities

• Search email across folders or restrict a search to one folder.
• Read, send, reply to, archive, and mark messages, subject to feature flags.
• Create and manage server-side mail filters using OX mail filters or ManageSieve.
• List calendar events and respond to invitations with accepted, declined, or tentative status.
• Find and list CardDAV contacts, including field-limited searches.
• Query free/busy availability using CalDAV and RFC 6638 support.

Mail filters support conditions on sender, recipient, subject, or arbitrary headers, combined with AND or OR logic. Available actions include moving mail to a folder, discarding it, marking it read, and redirecting it.

Limitations and notes

Write operations are disabled by default and must be enabled per section or through environment variables. RSVP tools share the respondEvent feature flag. When the imap transport is used, ox-mcp manages and activates its own Sieve script; other scripts can become inactive while it is active. Open-Xchange API search does not provide full message-body matching. The project states that it has no affiliation with Open-Xchange.