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mm-mcp

mm-mcp is an MCP server for Mattermost. It lets an AI agent read and search your Mattermost, and, when you allow it, post and reply, as you or as a bot.

mm-mcp is an independent project. It is not affiliated with, endorsed by or supported by Mattermost, Inc.; Mattermost is a trademark of Mattermost, Inc.

Early development

mm-mcp is young: its tools read, search, post and handle files, and are tested against a real Mattermost, but nothing is released yet. The issues are the plan.

What it is for

  • Reading and searching channels, threads, unread messages and mentions, and looking up people and channels.
  • Posting and replying, editing and deleting your own posts, reacting and pinning, once you allow writes, each confirmed by you before it is sent.
  • Your own things: following threads, saving posts, reminders, drafts and the typing indicator, once you allow writes, without a question each time.
  • Files and attachments, read, uploaded and saved to your machine.

Planned, not yet built: views in the chat, so that in a client that renders MCP Apps a thread appears as Mattermost lays it out and a draft appears before it is posted (ADR-022).

How it behaves

  • Read-only unless you say otherwise. The tools that post or change anything are not even offered until MM_MCP_ALLOW_WRITES is true. Then each change others see asks you first; following a thread, saving a post, a reminder, a draft only you see and the typing indicator do not (ADR-021).
  • One server, one identity. It acts as whoever owns the token it is given: a personal access token, a bot's token, or a session token from your own login (ADR-019).
  • stdio or HTTP. A desktop or IDE client starts it as a local process; over Streamable HTTP it serves a loopback address for now (ADR-020).
  • Tested against a real Mattermost. Every tool is exercised against Team Edition, on the current Extended Support Release and the newest release (ADR-004).

Next to Mattermost's own MCP server

Mattermost publishes an MCP server of its own, inside its Agents plugin. mm-mcp differs on purpose:

  • Any edition, no plugin. mm-mcp talks to Mattermost's REST API as a client does, so it runs against Team Edition as well; the other's write tools need an Enterprise licence, and it runs inside a plugin on the server.
  • As you. It acts with your own token or a bot's, and every post says it was written with AI.
  • Asks before every write others see, through your MCP client, showing what will be posted, where and as whom.
  • Tools shaped for an agent rather than one per endpoint: a post comes with its author, channel, team, files and reactions, and names are found as a person writes them (ADR-030).

Start with Installation.