Mattermost with DevFlow: setup, scope and limits

DevFlow connects to your Mattermost server as a bot and listens in allowlisted channels. A teammate mentions the bot, gets a read-only answer about the repository and can turn the thread into a task whose plan is approved by reply. Setup is 4 steps in Workspace Settings → Integrations.

Kind

Chat bridge

Where to set it up

Workspace Settings → Integrations

Plan

All plans

Agent roles

planning, summarizer

Verified

1 Oct 2026

Setup steps

1. Create a bot account. In Mattermost, create a bot account, copy its access token, and note the IDs of the team and of every channel the bot should serve.
2. Open the Integrations tab. As a workspace owner, open the Integrations tab of Workspace Settings and scroll to the chat bridge panels at the bottom.
3. Fill in the connection. Enter "Server URL", "Bot token", "Team ID" and "Channel IDs" as a comma-separated list.
4. Save and let DevFlow verify. Click "Save". DevFlow checks the address, calls /api/v4/users/me with the token and refuses the save with "could not authenticate bot token" when that call fails; on success the listener starts at once.

What it does

Unlike a webhook integration, DevFlow opens an outbound WebSocket to /api/v4/websocket on your server and sends the bot token as its authentication challenge. If the socket drops, the listener reconnects after 1 second and doubles the wait on each failure, up to 30 seconds.

Only posted events count, and only when the post mentions the bot or replies inside a thread. Replies go back through the REST endpoint /api/v4/posts, in the same thread as the question.

A first mention gets an answer from the planning role, which reads the default branch of the workspace's first repository with Read, Grep and Glob for up to 3 minutes. Replying go then turns the conversation into a task, and the thread receives the planner's questions, the plan with a link and the final pull request links.

Each author is identified by the email of their Mattermost account, read through the bot. DevFlow rejects an unverified email by default, because an address a user can set freely must not grant someone else's DevFlow identity.

The server address is checked twice: when the connection is saved, and again for each dial, so a later DNS change cannot point the bot at an internal host.

Every outbound post is defanged first: @channel, @here and @all in agent-written text get a zero-width space, so a plan or a title can never notify a whole channel.

If an exploration fails, or the workspace is over its monthly budget, the thread gets a short apology pointing to DevFlow instead of an answer. A second message that arrives while an exploration is still running does not start another one.

Requirements

• A server reachable from DevFlow at a public address over http or https.
• A bot token: the server URL and the token are both required on every save.
• The owner role in the DevFlow workspace; members can read the connection status but cannot change it.
• Authors whose account email is verified (by default), belongs to a DevFlow workspace member or an instance admin, and passes the login domain check.

Limits

• Addresses that resolve to loopback, private, link-local, unspecified or multicast ranges are refused.
• A channel can belong to one DevFlow workspace only, and messages from channels outside the saved list are dropped.
• Each author can send 15 messages per minute per workspace before further messages are dropped silently.

Sources

Every fact above comes from these files in the DevFlow repository.

• internal/mattermost/listener.go
• internal/mattermost/client.go
• internal/mattermost/safeurl.go
• internal/mattermost/provider.go
• internal/api/handlers_chat.go
• internal/api/server.go
• internal/api/chat_pipeline.go
• internal/chatbridge/bridge.go
• internal/chatbridge/intent.go
• internal/chatbridge/outbox.go
• internal/agent/planning.go
• internal/notify/dispatcher.go
• internal/api/handlers_notification.go
• web/src/lib/components/MattermostConnect.svelte
• web/src/lib/components/WorkspaceSettings.svelte