Add Mattermost

Add Mattermost Channel

Adds Mattermost DMs, channels, threads, files, reactions, and interactive approval cards. Messages arrive over Mattermost's WebSocket; card clicks return to NanoClaw over an authenticated HTTP callback. Every step is safe to re-run.

Discover the server first

Do this before installing the adapter or asking for a URL. The goal is to reuse a healthy Mattermost the user already has and establish one canonical base URL.

1. Check an existing MATTERMOST_BASE_URL in the current environment and NanoClaw env/config files. Do not print tokens or dump whole env files.
2. Probe likely local URLs, at least http://localhost:8065 and http://127.0.0.1:8065, using GET /api/v4/system/ping. A listening port alone is not evidence that the service is Mattermost.
3. Inspect Docker/Compose for Mattermost containers. If a matching container exists but is stopped, offer to start it; do not start or recreate it without the user's approval.
4. If one healthy server is found, tell the user and use it. If multiple distinct servers are found, ask which one to use. Treat localhost and 127.0.0.1 endpoints for the same container as one server and prefer the hostname in its configured Site URL; otherwise prefer localhost.
5. If nothing local is found, ask whether the user has a remote Mattermost. If not, offer the local evaluation installation in LOCAL_SERVER.md. Read that file only for local server discovery, repair, or installation.

Set MATTERMOST_BASE_URL to the chosen canonical URL (scheme included, no trailing slash), then use that exact hostname in browser/Desktop setup. Do not silently install Mattermost: it runs containers, binds a port, and persists data, so show what will be created and get approval first.

Apply

1. Detect the server

Probe a configured URL and the conventional local endpoints. The detector always returns structured output: found binds base_url; none leaves it for the guarded prompt below.

node .claude/skills/add-mattermost/scripts/discover-server.mjs

No healthy configured or local Mattermost server was detected. If you have a remote server, provide its URL next. Otherwise install the local evaluation server by following LOCAL_SERVER.md, then provide http://localhost:8065.

Mattermost base URL including the scheme, such as `https://mattermost.example.com`.

2. Copy and register the channel

Copy the canonical adapter and registration test from the channels branch.

src/channels/mattermost.ts
src/channels/mattermost-registration.test.ts
src/channels/mattermost-adapter/adapter.ts
src/channels/mattermost-adapter/format.ts
src/channels/mattermost-adapter/index.ts
src/channels/mattermost-adapter/rest.ts
src/channels/mattermost-adapter/thread-id.ts
src/channels/mattermost-adapter/types.ts
src/channels/mattermost-adapter/websocket.ts

Append the channel's single reach-in to the barrel, skipping it if present.

import './mattermost.js';

Remove the unscoped chat-adapter-mattermost package when it is installed. Nothing in this repository imports it: it is typosquat-shaped against the scoped @chat-adapter family, so any copy in package.json is stale or mistaken and would sit beside the audited implementation copied from the channels branch.

if node -e "const p=require('./package.json'); process.exit(p.dependencies?.['chat-adapter-mattermost'] ? 0 : 1)"; then pnpm remove chat-adapter-mattermost; fi

Install the vendored adapter's direct WebSocket dependencies at the exact supported versions.

ws@8.21.3
@types/ws@8.18.1

3. Create and authenticate the bot

Tell the operator:

Create a dedicated Mattermost bot:
1. As a System Admin, open System Console → Integrations → Bot Accounts and enable bot-account creation.
2. Create a bot such as `nanoclaw`, then copy the access token shown after creation.
3. Add the bot to every team and channel where it should receive messages. Bots do not join channels automatically.
4. Keep the token private. If it is lost, create a new token and deactivate the obsolete one after replacement.

Mattermost bot access token (20 or more letters, digits, underscores, or hyphens).

Confirm the credential and capture the bot identity. A failure means the URL, token, or bot-account status is wrong.

curl -sf "{{base_url}}/api/v4/users/me" -H "Authorization: Bearer {{bot_token}}"

4. Configure authenticated card callbacks

Approvals require Mattermost itself—not the browser—to reach NanoClaw. Ask for a URL routable from the Mattermost server. It may be NanoClaw's base URL or the full /webhook/mattermost route; the adapter normalizes either form.

Callback URL reachable from Mattermost, such as `https://nanoclaw.example.com` or `http://host.docker.internal:3000/webhook/mattermost`.

Mattermost does not sign action callbacks. Generate a random shared secret for the server-only callback context.

openssl rand -hex 32

Store the channel configuration. Existing keys remain unchanged on a re-run.

MATTERMOST_BASE_URL={{base_url}}
MATTERMOST_BOT_TOKEN={{bot_token}}
MATTERMOST_CALLBACK_URL={{callback_url}}
MATTERMOST_CALLBACK_SECRET={{callback_secret}}

Tell the operator:

From the Mattermost server, verify the callback host is reachable. For a private host or Docker bridge name, add that hostname or IP under System Console → Environment → Developer → Allow untrusted internal connections. Use a publicly trusted HTTPS certificate in production.

5. Resolve the owner's DM

Ask for the Mattermost username that will own this NanoClaw installation.

Your Mattermost username, without `@`.

Resolve that user and open the DM shared with the bot.

curl -sf "{{base_url}}/api/v4/users/username/{{owner_username}}" -H "Authorization: Bearer {{bot_token}}"

curl -sf -X POST "{{base_url}}/api/v4/channels/direct" -H "Authorization: Bearer {{bot_token}}" -H "Content-Type: application/json" -d '["{{owner_user_id}}","{{bot_user_id}}"]' | jq -er '"mattermost:" + .id'

The resolved platform_id and owner_username are used by /init-first-agent. If an owner exists, use /manage-channels instead.

6. Build, test, and restart

Build the composed host to guard the typed Chat SDK bridge call and dependency.

pnpm run build

Run the registration test through the real channel barrel.

pnpm exec vitest run src/channels/mattermost-registration.test.ts

Restart NanoClaw so the channel and credentials load.

bash setup/lib/restart.sh

Next steps

For a first channel, continue with /init-first-agent using mattermost, {{platform_id}}, and {{owner_username}}. Otherwise run /manage-channels.

Send the bot a DM and mention it in a joined channel. The first mention in an unwired channel sends an approval card to the owner's bot DM. Approve it there; NanoClaw replays the held message after creating the wiring.

Click a real approval card to verify callbacks. Success replaces the buttons with the chosen result. An unsigned probe must return 401:

curl -sS -o /dev/null -w '%{http_code}\n' -X POST \
  -H 'content-type: application/json' -d '{}' \
  http://<nanoclaw-host>:3000/webhook/mattermost

Channel information

• type: mattermost
• platform ID: mattermost:<channel-id> for channels and DMs
• threads: channel posts use optional Mattermost reply roots
• group trigger: mention-sticky, scoped per thread
• DM trigger: every message
• unknown channels: request owner approval
• transport: WebSocket inbound, REST outbound, HTTP action callbacks

Troubleshooting

The token check returns 401. The token is stale, belongs to a deactivated bot, or was pasted incorrectly. Create a replacement token and deactivate the old token after the replacement works.

The bot ignores a channel. Add it to that team and channel. Membership changes are observed, but restarting NanoClaw forces a fresh subscription.

A new channel gets no immediate reply. Check the owner's DM with the bot. NanoClaw holds the first message behind a channel-approval card and deduplicates later mentions until that card is resolved.

Desktop messages appear only after a manual refresh. This is usually the Desktop client's WebSocket origin being rejected. Keep the Desktop server URL, MATTERMOST_BASE_URL, and Mattermost ServiceSettings.SiteURL on the same canonical hostname. Check server logs for request origin not allowed, and verify /api/v4/websocket returns 101 Switching Protocols for that Origin. For a local server that genuinely needs both hostnames, persist a space-separated ServiceSettings.AllowCorsFrom containing http://localhost:8065 and http://127.0.0.1:8065; do not use *. Preview images may regenerate config.json on restart, so make the setting part of container startup rather than relying on an in-container edit.

Cards render but clicks do nothing. From the Mattermost server, POST to the callback URL. A 401 proves the path reaches NanoClaw; timeout or refusal means routing or firewall failure. Mattermost logs report blocked hosts and TLS errors.

The adapter repeatedly reconnects. Confirm /api/v4/websocket supports WebSocket upgrades through every reverse proxy and that idle connections live longer than the adapter heartbeat.

Messages arrive but no agent runs. Inspect ncl dropped-messages list and ncl wirings list. no_agent_wired means approval is pending or no wiring was created; it is not an adapter failure.