openclaw/docs/channels/mattermost.md

summary	read_when	title	sidebarTitle
Mattermost bot setup and OpenClaw config	Setting up Mattermost Debugging Mattermost routing	Mattermost	Mattermost

Status: downloadable plugin (bot token + WebSocket events). Channels, private channels, group DMs, and DMs are supported. Mattermost is a self-hostable team messaging platform (mattermost.com).

Install

```bash openclaw plugins install @openclaw/mattermost ``` ```bash openclaw plugins install ./path/to/local/mattermost-plugin ```

Details: Plugins

Quick setup

Install `@openclaw/mattermost` with the command above, then restart the Gateway if it is already running. Create a Mattermost bot account, copy the **bot token**, and add the bot to the teams and channels it should read. Copy the Mattermost **base URL** (e.g., `https://chat.example.com`). A trailing `/api/v4` is stripped automatically. Minimal config:

```json5
{
  channels: {
    mattermost: {
      enabled: true,
      botToken: "mm-token",
      baseUrl: "https://chat.example.com",
      dmPolicy: "pairing",
    },
  },
}
```

Non-interactive alternative:

```bash
openclaw channels add --channel mattermost --bot-token <token> --http-url https://chat.example.com
```

Self-hosted Mattermost on a private/LAN/tailnet address: outbound Mattermost API requests pass through an SSRF guard that blocks private and internal IPs by default. Opt in with `channels.mattermost.network.dangerouslyAllowPrivateNetwork: true` (per account: `channels.mattermost.accounts..network.dangerouslyAllowPrivateNetwork`).

Native slash commands

Native slash commands are opt-in. When enabled, OpenClaw registers oc_* slash commands on every team the bot is a member of and receives callback POSTs on the gateway HTTP server.

{
  channels: {
    mattermost: {
      commands: {
        native: true,
        nativeSkills: true,
        callbackPath: "/api/channels/mattermost/command",
        // Use when Mattermost cannot reach the gateway directly (reverse proxy/public URL).
        callbackUrl: "https://gateway.example.com/api/channels/mattermost/command",
      },
    },
  },
}

Registered commands: /oc_status, /oc_model, /oc_models, /oc_new, /oc_help, /oc_think, /oc_reasoning, /oc_verbose, /oc_queue. With nativeSkills: true, skill commands are also registered as /oc_<skill>.

- `native` and `nativeSkills` default to `"auto"`, which resolves to disabled for Mattermost. Set them to `true` explicitly. - `callbackPath` defaults to `/api/channels/mattermost/command`. - If `callbackUrl` is omitted, OpenClaw derives `http://:`. Wildcard bind hosts (`0.0.0.0`, `::`) fall back to `localhost`. - For multi-account setups, `commands` can be set at the top level or under `channels.mattermost.accounts..commands` (account values override top-level fields). - Existing slash commands with the same trigger created by other integrations are left untouched (registration skips them); commands the bot created are updated or recreated when the callback URL drifts. - Command callbacks are validated with the per-command tokens returned by Mattermost when OpenClaw registers `oc_*` commands. - OpenClaw refreshes current Mattermost command registration before accepting each callback, so stale tokens from deleted or regenerated slash commands stop being accepted without a gateway restart. - Callback validation fails closed if the Mattermost API cannot confirm the command is still current; failed validations are cached briefly, concurrent lookups are coalesced, and fresh lookup starts are rate-limited per command to bound replay pressure. - Slash callbacks fail closed when registration failed, startup was partial, or the callback token does not match the resolved command's registered token (a token valid for one command cannot reach upstream validation for a different command). - Accepted callbacks are acknowledged with an ephemeral "Processing..." reply; the real answer arrives as a normal message. The callback endpoint must be reachable from the Mattermost server.

- Do not set `callbackUrl` to `localhost` unless Mattermost runs on the same host/network namespace as OpenClaw.
- Do not set `callbackUrl` to your Mattermost base URL unless that URL reverse-proxies `/api/channels/mattermost/command` to OpenClaw.
- A quick check is `curl https://<gateway-host>/api/channels/mattermost/command`; a GET should return `405 Method Not Allowed` from OpenClaw, not `404`.

If your callback targets private/tailnet/internal addresses, set Mattermost `ServiceSettings.AllowedUntrustedInternalConnections` to include the callback host/domain.

Use host/domain entries, not full URLs.

- Good: `gateway.tailnet-name.ts.net`
- Bad: `https://gateway.tailnet-name.ts.net`

Environment variables (default account)

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_URL cannot be set from a workspace .env; see Workspace .env files.

Chat modes

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

Respond only when @mentioned in channels. Respond to every channel message. Respond when a message starts with a trigger prefix.

Config example:

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

Notes:

• onchar still responds to explicit @mentions.
• channels.mattermost.requireMention is still honored, but chatmode is preferred. Per-channel groups.<channelId>.requireMention settings win over both.
• After the bot sends a visible reply in a channel thread, later messages in that same thread are answered without a new @mention or onchar prefix, so multi-turn thread conversations keep flowing. Participation is remembered for 7 days after the bot last replied in that thread and persists across gateway restarts. Threads the bot has only observed are unaffected; start a new top-level message to require an explicit mention again.

Threading and sessions

Use channels.mattermost.replyToMode to control whether channel and group replies stay in the main channel or start a thread under the triggering post.

• off (default): only reply in a thread when the inbound post is already in one.
• first: for top-level channel/group posts, start a thread under that post and route the conversation to a thread-scoped session.
• all and batched: same behavior as first for Mattermost today, because once Mattermost has a thread root, follow-up chunks and media continue in that same thread.
• Direct messages ignore this setting and stay non-threaded.

{
  channels: {
    mattermost: {
      replyToMode: "all",
    },
  },
}

Thread-scoped sessions use the triggering post id as the thread root.

Access control (DMs)

• Default: channels.mattermost.dmPolicy = "pairing" (unknown senders get a pairing code). Other values: allowlist, open, disabled.
• Approve via:
  • openclaw pairing list mattermost
  • openclaw pairing approve mattermost <CODE>
• Public DMs: channels.mattermost.dmPolicy="open" plus channels.mattermost.allowFrom=["*"] (the config schema enforces the wildcard).
• channels.mattermost.allowFrom accepts user ids (recommended) and accessGroup:<name> entries. See Access groups.

Channels (groups)

• Default: channels.mattermost.groupPolicy = "allowlist" (mention-gated).
• Allowlist senders with channels.mattermost.groupAllowFrom (user IDs recommended).
• channels.mattermost.groupAllowFrom accepts accessGroup:<name> entries. See Access groups.
• Per-channel mention overrides live under channels.mattermost.groups.<channelId>.requireMention or channels.mattermost.groups["*"].requireMention for a default.
• @username matching is mutable and only enabled when channels.mattermost.dangerouslyAllowNameMatching: true.
• Open channels: channels.mattermost.groupPolicy="open" (mention-gated).
• Resolution order: channels.mattermost.groupPolicy, then channels.defaults.groupPolicy, then "allowlist".
• Runtime note: if the channels.mattermost section is completely missing, runtime fails closed to groupPolicy="allowlist" for group checks (even if channels.defaults.groupPolicy is set) and logs a one-time warning.

Example:

{
  channels: {
    mattermost: {
      groupPolicy: "open",
      groups: {
        "*": { requireMention: true },
        "team-channel-id": { requireMention: false },
      },
    },
  },
}

Targets for outbound delivery

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

Target	Delivers to
channel:<id>	Channel by id
channel:<name> or #channel-name	Channel by name, searched across the teams the bot belongs to
user:<id> or mattermost:<id>	DM with that user
@username	DM (username resolved via the Mattermost API)

Outbound sends support at most one attachment per message; split multiple files into separate sends.

Bare opaque IDs (like `64ifufp...`) are **ambiguous** in Mattermost (user ID vs channel ID).

OpenClaw resolves them user-first:

• If the ID exists as a user (GET /api/v4/users/<id> succeeds), OpenClaw sends a DM by resolving the direct channel via /api/v4/channels/direct.
• Otherwise the ID is treated as a channel ID.

If you need deterministic behavior, always use the explicit prefixes (user:<id> / channel:<id>).

DM channel retry

When OpenClaw sends to a Mattermost DM target and needs to resolve the direct channel first, it retries transient direct-channel creation failures by default.

Use channels.mattermost.dmChannelRetry to tune that behavior globally for the Mattermost plugin, or channels.mattermost.accounts.<id>.dmChannelRetry for one account. Defaults:

{
  channels: {
    mattermost: {
      dmChannelRetry: {
        maxRetries: 3,
        initialDelayMs: 1000,
        maxDelayMs: 10000,
        timeoutMs: 30000,
      },
    },
  },
}

Notes:

• This applies only to DM channel creation (/api/v4/channels/direct), not every Mattermost API call.
• Retries use exponential backoff with jitter and apply to transient failures such as rate limits, 5xx responses, and network or timeout errors.
• 4xx client errors other than 429 are treated as permanent and are not retried.

Preview streaming

Mattermost streams thinking, tool activity, and partial reply text into a single draft preview post that finalizes in place when the final answer is safe to send. The preview updates on the same post id instead of spamming the channel with per-chunk messages. Media/error finals cancel pending preview edits and use normal delivery instead of flushing a throwaway preview post.

Preview streaming is on by default in partial mode. Configure via channels.mattermost.streaming (a mode string, boolean, or an object like { mode: "progress" }):

{
  channels: {
    mattermost: {
      streaming: "partial", // off | partial | block | progress
    },
  },
}

- `partial` (default): one preview post that is edited as the reply grows, then finalized with the complete answer. - `block` uses append-style draft chunks inside the preview post. - `progress` shows a status preview while generating and only posts the final answer at completion. - `off` disables preview streaming. - If the stream cannot be finalized in place (for example the post was deleted mid-stream), OpenClaw falls back to sending a fresh final post so the reply is never lost. - Thinking-only payloads are suppressed from channel posts, including text that arrives as a `> Thinking` blockquote. Set `/reasoning on` to see thinking in other surfaces; the Mattermost final post keeps the answer only. - See [Streaming](/concepts/streaming#preview-streaming-modes) for the channel-mapping matrix.

Reactions (message tool)

• Use message action=react with channel=mattermost.
• messageId is the Mattermost post id.
• emoji accepts names like thumbsup or :+1: (colons are optional).
• Set remove=true (boolean) to remove a reaction.
• Reaction add/remove events are forwarded as system events to the routed agent session, subject to the same DM/group policy checks as messages.

Examples:

message action=react channel=mattermost target=channel:<channelId> messageId=<postId> emoji=thumbsup
message action=react channel=mattermost target=channel:<channelId> messageId=<postId> emoji=thumbsup remove=true

Config:

• channels.mattermost.actions.reactions: enable/disable reaction actions (default true).
• Per-account override: channels.mattermost.accounts.<id>.actions.reactions.

Interactive buttons (message tool)

Send messages with clickable buttons. When a user clicks a button, the agent receives the selection and can respond.

Buttons come from the semantic presentation payload (in normal agent replies and in message action=send). OpenClaw renders value buttons as Mattermost interactive buttons, keeps URL buttons visible in the message text, and downgrades select menus to readable text.

message action=send channel=mattermost target=channel:<channelId> presentation={"blocks":[{"type":"buttons","buttons":[{"label":"Yes","value":"yes"},{"label":"No","value":"no"}]}]}

Presentation button fields:

Display label (alias: `text`). Value sent back on click, used as the action ID (aliases: `callback_data`, `callbackData`). Required for a clickable button unless `url` is set. Link button; rendered as `label: url` text in the message body instead of an interactive button. Button style. Mattermost applies default styling to values it does not support.

To advertise button support in the agent system prompt, add inlineButtons to the channel capabilities:

{
  channels: {
    mattermost: {
      capabilities: ["inlineButtons"],
    },
  },
}

When a user clicks a button:

The clicker must pass the same DM/group policy checks as a message sender; unauthorized clicks get an ephemeral notice and are ignored. All buttons are replaced with a confirmation line (e.g., "✓ **Yes** selected by @user"). The agent receives the selection as an inbound message (plus a system event) and responds. - Button callbacks use HMAC-SHA256 verification (automatic, no config needed). - The whole attachment block is replaced on click, so all buttons are removed together - partial removal is not possible. - Action IDs containing hyphens or underscores are sanitized automatically (Mattermost routing limitation). - Clicks whose `action_id` does not match an action on the original post are rejected with `403` ("Unknown action"). - `channels.mattermost.capabilities`: array of capability strings. Add `"inlineButtons"` to enable the buttons tool description in the agent system prompt. - `channels.mattermost.interactions.callbackBaseUrl`: optional external base URL for button callbacks (for example `https://gateway.example.com`). Use this when Mattermost cannot reach the gateway at its bind host directly. - In multi-account setups, you can also set the same field under `channels.mattermost.accounts..interactions.callbackBaseUrl`. - If `interactions.callbackBaseUrl` is omitted, OpenClaw derives the callback URL from `gateway.customBindHost` + `gateway.port` (default 18789), then falls back to `http://localhost:`. The callback path is `/mattermost/interactions/`. - Reachability rule: the button callback URL must be reachable from the Mattermost server. `localhost` only works when Mattermost and OpenClaw run on the same host/network namespace. - `channels.mattermost.interactions.allowedSourceIps`: source-IP allowlist for button callbacks. Without it, only loopback sources (`127.0.0.1`, `::1`) are accepted, so a remote Mattermost server must be allowlisted here or its clicks are rejected with `403`. Behind a reverse proxy, also set `gateway.trustedProxies` so the real client IP is derived from forwarded headers. - If your callback target is private/tailnet/internal, add its host/domain to Mattermost `ServiceSettings.AllowedUntrustedInternalConnections`.

Direct API integration (external scripts)

External scripts and webhooks can post buttons directly via the Mattermost REST API instead of going through the agent's message tool. Use buildButtonAttachments() from the plugin when possible; if posting raw JSON, follow these rules:

Payload structure:

{
  channel_id: "<channelId>",
  message: "Choose an option:",
  props: {
    attachments: [
      {
        actions: [
          {
            id: "mybutton01", // alphanumeric only - see below
            type: "button", // required, or clicks are silently ignored
            name: "Approve", // display label
            style: "primary", // optional: "default", "primary", "danger"
            integration: {
              url: "https://gateway.example.com/mattermost/interactions/default",
              context: {
                action_id: "mybutton01", // must match button id
                action: "approve",
                // ... any custom fields ...
                _token: "<hmac>", // see HMAC section below
              },
            },
          },
        ],
      },
    ],
  },
}

**Critical rules**

1. Attachments go in props.attachments, not top-level attachments (silently ignored).
2. Every action needs type: "button" - without it, clicks are swallowed silently.
3. Every action needs an id field - Mattermost ignores actions without IDs.
4. Action id must be alphanumeric only ([a-zA-Z0-9]). Hyphens and underscores break Mattermost's server-side action routing (returns 404). Strip them before use.
5. context.action_id must match the button's id; the gateway rejects clicks whose action_id does not exist on the post.
6. context.action_id is required - the interaction handler returns 400 without it.
7. The callback source IP must be allowed (see interactions.allowedSourceIps above).

HMAC token generation

The gateway verifies button clicks with HMAC-SHA256. External scripts must generate tokens that match the gateway's verification logic:

`HMAC-SHA256(key="openclaw-mattermost-interactions", data=botToken)`, hex-encoded. Build the context object with all fields **except** `_token`. Serialize with **recursively sorted keys** and **no spaces** (the gateway canonicalizes nested objects too and produces compact JSON). `HMAC-SHA256(key=secret, data=serializedContext)` Add the resulting hex digest as `_token` in the context.

Python example:

import hmac, hashlib, json

secret = hmac.new(
    b"openclaw-mattermost-interactions",
    bot_token.encode(), hashlib.sha256
).hexdigest()

ctx = {"action_id": "mybutton01", "action": "approve"}
payload = json.dumps(ctx, sort_keys=True, separators=(",", ":"))
token = hmac.new(secret.encode(), payload.encode(), hashlib.sha256).hexdigest()

context = {**ctx, "_token": token}

- Python's `json.dumps` adds spaces by default (`{"key": "val"}`). Use `separators=(",", ":")` to match JavaScript's compact output (`{"key":"val"}`). - Always sign **all** context fields (minus `_token`). The gateway strips `_token` then signs everything remaining. Signing a subset causes silent verification failure. - Use `sort_keys=True` - the gateway sorts keys before signing, and Mattermost may reorder context fields when storing the payload. - Derive the secret from the bot token (deterministic), not random bytes. The secret must be the same across the process that creates buttons and the gateway that verifies.

Directory adapter

The Mattermost plugin includes a directory adapter that resolves channel and user names via the Mattermost API. This enables #channel-name and @username targets in openclaw message send and cron/webhook deliveries.

No configuration is needed - the adapter uses the bot token from the account config.

Multi-account

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" },
      },
    },
  },
}

Account values override top-level fields; channels.mattermost.defaultAccount picks which account is used when none is specified.

Troubleshooting

Ensure the bot is in the channel and mention it (oncall), use a trigger prefix (onchar), or set `chatmode: "onmessage"`. - Check the bot token, base URL, and whether the account is enabled. - Multi-account issues: env vars only apply to the `default` account. - Private/LAN Mattermost hosts need `network.dangerouslyAllowPrivateNetwork: true` (the SSRF guard blocks private IPs by default). - `Unauthorized: invalid command token.`: OpenClaw did not accept the callback token. Typical causes: - slash command registration failed or only partially completed at startup - the callback is hitting the wrong gateway/account - Mattermost still has old commands pointing at a previous callback target - the gateway restarted without reactivating slash commands - If native slash commands stop working, check logs for `mattermost: failed to register slash commands` or `mattermost: native slash commands enabled but no commands could be registered`. - If `callbackUrl` is omitted and logs warn that the callback resolved to a loopback URL like `http://localhost:18789/...`, that URL is probably only reachable when Mattermost runs on the same host/network namespace as OpenClaw. Set an explicit externally reachable `commands.callbackUrl` instead. - Buttons appear as white boxes or not at all: the button data is malformed. Each presentation button needs a `label` and a `value` (buttons missing either are dropped). - Buttons render but clicks do nothing: verify the gateway is reachable from the Mattermost server, the Mattermost server IP is included in `channels.mattermost.interactions.allowedSourceIps` (only loopback is accepted without it), and `ServiceSettings.AllowedUntrustedInternalConnections` includes the callback host for private targets. - Buttons return 404 on click: the button `id` likely contains hyphens or underscores. Mattermost's action router breaks on non-alphanumeric IDs. Use `[a-zA-Z0-9]` only. - Gateway logs `rejected callback source`: the click came from an IP outside `interactions.allowedSourceIps`. Allowlist the Mattermost server or your ingress, and set `gateway.trustedProxies` behind a reverse proxy. - Gateway logs `invalid _token`: HMAC mismatch. Check that you sign all context fields (not a subset), use sorted keys, and use compact JSON (no spaces). See the HMAC section above. - Gateway logs `missing _token in context`: the `_token` field is not in the button's context. Ensure it is included when building the integration payload. - Gateway rejects the click with `Unknown action`: `context.action_id` does not match any action `id` on the post. Set both to the same sanitized value. - Agent does not offer buttons: add `capabilities: ["inlineButtons"]` to the Mattermost channel config.

Related

• Channel Routing - session routing for messages
• Channels Overview - all supported channels
• Groups - group chat behavior and mention gating
• Pairing - DM authentication and pairing flow
• Security - access model and hardening