Status: supported via plugin (bot token + WebSocket events). Channels, groups, and DMs are supported. Mattermost is a self-hostable team messaging platform; see the official site at mattermost.com for product details and downloads.

Mattermost ships as a plugin and is not bundled with the core install.

Install via CLI (npm registry):

openclaw plugins install @openclaw/mattermost

Local checkout (when running from a git repo):

openclaw plugins install ./extensions/mattermost

If you choose Mattermost during configure/onboarding and a git checkout is detected, OpenClaw will offer the local install path automatically.

Details: Plugins

1. Install the Mattermost plugin.
2. Create a Mattermost bot account and copy the bot token.
3. Copy the Mattermost base URL (e.g., https://chat.example.com).
4. Configure OpenClaw and start the gateway.

Minimal config:

{
  channels: {
    mattermost: {
      enabled: true,
      botToken: "mm-token",
      baseUrl: "https://chat.example.com",
      dmPolicy: "pairing"
    }
  }
}

Set these on the gateway host if you prefer env vars:

• MATTERMOST_BOT_TOKEN=...
• MATTERMOST_URL=https://chat.example.com

Env vars apply only to the default account (default). Other accounts must use config values.

Mattermost responds to DMs automatically. Channel behavior is controlled by chatmode:

• oncall (default): respond only when @mentioned in channels.
• onmessage: respond to every channel message.
• onchar: respond when a message starts with a trigger prefix.

Config example:

{
  channels: {
    mattermost: {
      chatmode: "onchar",
      oncharPrefixes: [">", "!"]
    }
  }
}

Notes:

• onchar still responds to explicit @mentions.
• channels.mattermost.requireMention is honored for legacy configs but chatmode is preferred.

• Default: channels.mattermost.dmPolicy = "pairing" (unknown senders get a pairing code).
• Approve via:
  • openclaw pairing list mattermost
  • openclaw pairing approve mattermost <CODE>
• Public DMs: channels.mattermost.dmPolicy="open" plus channels.mattermost.allowFrom=["*"].

• Default: channels.mattermost.groupPolicy = "allowlist" (mention-gated).
• Allowlist senders with channels.mattermost.groupAllowFrom (user IDs or @username).
• Open channels: channels.mattermost.groupPolicy="open" (mention-gated).

Use these target formats with openclaw message send or cron/webhooks:

• channel:<id> for a channel
• user:<id> for a DM
• @username for a DM (resolved via the Mattermost API)

Bare IDs are treated as channels.

Mattermost supports multiple accounts under channels.mattermost.accounts:

{
  channels: {
    mattermost: {
      accounts: {
        default: { name: "Primary", botToken: "mm-token", baseUrl: "https://chat.example.com" },
        alerts: { name: "Alerts", botToken: "mm-token-2", baseUrl: "https://alerts.example.com" }
      }
    }
  }
}

• No replies in channels: ensure the bot is in the channel and mention it (oncall), use a trigger prefix (onchar), or set chatmode: "onmessage".
• Auth errors: check the bot token, base URL, and whether the account is enabled.
• Multi-account issues: env vars only apply to the default account.