Mattermost MCP

What conarti/mattermost-mcp MCP server does

The conarti/mattermost-mcp MCP server connects an MCP client to a Mattermost workspace through the Mattermost API. It supports both read and write workflows: an agent can discover channels, retrieve messages, publish new messages, respond in threads, add reactions, and inspect users.

The server also includes topic monitoring. Monitoring can inspect configured channels for messages containing configured topics, run on a cron-style schedule, and send notifications when matching discussions are found. A monitoring run can be triggered manually through an MCP tool or at process startup.

How it works

The process requires three pieces of Mattermost configuration: the API URL, a personal access token, and a team ID. Configuration can be supplied as command-line options, environment variables, or JSON files. Command-line values take precedence over environment variables, which take precedence over config.local.json and then config.json.

For channel history, the client can request a fixed number of messages, all messages, date-bounded results, or cursor-based results using post IDs. Channel listing supports pagination and can optionally include private channels and direct messages.

Setup and configuration

The published npm package can be run with npx:

npx -y @conarti/mattermost-mcp

The required environment variables are MATTERMOST_URL, MATTERMOST_TOKEN, and MATTERMOST_TEAM_ID. Equivalent command-line options are --url, --token, and --team-id. The API URL normally ends with /api/v4.

A JSON configuration can also define monitoring settings, including whether monitoring is enabled, its cron schedule, channels, topics, message limit, and optional notification or user identifiers. The --run-monitoring option starts a monitoring pass immediately; adding --exit-after-monitoring makes the process stop afterward, which supports scheduled command-line use.

Tools and capabilities

The conarti/mattermost-mcp MCP server provides tools for:

• Listing channels and retrieving channel history
• Posting messages and replying to threads
• Adding reactions and reading thread replies
• Listing workspace users and retrieving user profiles
• Triggering topic monitoring on demand

History queries accept channel IDs and can use limits, pages, date filters, or before/after post IDs. Monitoring uses configured channels and topic strings rather than an unrestricted workspace search.

Limitations and notes

The server needs a valid Mattermost personal access token with sufficient permissions, along with a correct API URL and team ID. Private channels and direct messages are not included in channel results by default; the caller must request them through the relevant option. When no history limit is provided, the history tool returns all messages, so callers should choose a limit or other filters when handling large channels. Monitoring configuration is separate from basic channel and messaging access and may require notification settings to be specified.