turnstone/docs/channels.md

Channel Integrations

The turnstone-channel gateway connects external messaging platforms to turnstone workstreams via Redis MQ. Each platform adapter translates platform-native events (messages, button clicks, slash commands) into turnstone MQ messages, and renders workstream output back into the platform's UI.

Discord ships as the first adapter. The adapter protocol is designed for future Slack and Teams integrations.

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Architecture

Discord Gateway
      |
      v
turnstone-channel  (Discord adapter)
      |
      v
  Redis MQ
      |
      v
turnstone-bridge  ──>  turnstone-server

Key components:

• ChannelAdapter protocol (turnstone/channels/_protocol.py) — generic interface for any messaging platform. Defines start(), stop(), send(), edit_message(), send_approval_request(), send_plan_review(), and create_thread().
• ChannelRouter (turnstone/channels/_routing.py) — maps channel/thread IDs to turnstone workstream IDs. Handles workstream creation via MQ, stale route detection, and user identity resolution.
• AsyncRedisBroker (turnstone/mq/async_broker.py) — async Redis client compatible with discord.py's event loop. Used by the router for pub/sub and queue operations.
• channel_users table — maps (channel_type, channel_user_id) to a turnstone user_id. Messages from unlinked users are silently dropped.
• channel_routes table — persistent channel-to-workstream mappings. Survives bot restarts. Stale routes (evicted workstreams) are detected and refreshed on the next message.

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Discord Setup

1. Create a Discord Application

1. Go to https://discord.com/developers/applications
2. Click New Application and give it a name
3. Navigate to the Bot tab and click Reset Token to generate a bot token. Copy it immediately — it is shown only once.
4. On the same Bot tab, scroll down to Privileged Gateway Intents and enable MESSAGE CONTENT INTENT
5. Navigate to OAuth2 > URL Generator
6. Under Scopes, check bot and applications.commands
7. Under Bot Permissions, check:
   • View Channels
   • Send Messages
   • Send Messages in Threads
   • Create Public Threads
   • Read Message History
   • Add Reactions
   • Embed Links
8. Copy the generated URL, open it in a browser, and add the bot to your Discord server

2. Configure Turnstone

Environment variables (recommended for Docker):

TURNSTONE_DISCORD_TOKEN=your-bot-token-here
TURNSTONE_DISCORD_GUILD=123456789  # optional, restrict to one guild

CLI flags (bare-metal):

turnstone-channel \
  --discord-token "your-bot-token" \
  --discord-guild 123456789 \
  --redis-host localhost \
  --redis-port 6379

Docker Compose (production profile):

# In .env file:
TURNSTONE_DISCORD_TOKEN=your-bot-token
TURNSTONE_DISCORD_GUILD=123456789

Then start the stack:

docker compose --profile production up

The channel service starts automatically when TURNSTONE_DISCORD_TOKEN is set.

3. Link User Accounts

Discord users must link their account to a turnstone user before they can interact with the bot. Unlinked users' messages are silently ignored.

1. The user must have a turnstone API token — created via the admin panel or turnstone-admin create-token
2. In Discord, the user runs /link. A modal appears prompting for the API token (the token is never visible in Discord audit logs because it is submitted via modal, not as a slash command argument).
3. The token is validated against the database. If valid, a channel_users mapping is created.
4. The user can now @mention the bot or use slash commands.

An admin can also force-link or unlink users via the console admin panel (Admin > Channels tab).

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Usage

Conversations

• @mention the bot in any allowed channel to start a new conversation. The bot creates a Discord thread from the message and a turnstone workstream behind it.
• All subsequent messages in the thread are routed to the same workstream.
• The bot streams responses via message edits, updated approximately every 1.5 seconds.
• If the workstream is evicted for capacity, the next message in the thread auto-creates a new workstream and atomically resumes the previous session via the resume_session field on CreateWorkstreamMessage. The server resumes the session during workstream creation (same HTTP request), and the bridge emits a SessionResumedEvent back to the channel. The thread receives a "Session resumed: {name} ({count} messages restored)" confirmation.

Slash Commands

Command	Description
/link	Link Discord account to turnstone (opens modal for API token)
/unlink	Unlink Discord account
/ask <message>	Create a new thread and workstream with an initial message
/status	Show workstream info for the current thread (ephemeral)
/close	Close the workstream, delete the route, and archive the thread

Tool Approvals

When manual approval is enabled (the default), tool calls are displayed as an orange embed with:

• Tool name and argument preview
• Approve (green), Reject (red), Always Approve (gray) buttons
• Only linked users can interact with approval buttons
• The approval decision is forwarded through MQ to the bridge, which relays it to the server

Buttons use static custom_id values so they survive bot restarts. Correlation data (ws_id, correlation_id) is stored in the embed footer.

Auto-approval: When auto_approve is true (via --auto-approve), or when all tools in the request match the auto_approve_tools list in the adapter config, the bot auto-responds with approval and posts a "Tool auto-approved." notice to the thread instead of showing buttons. The auto_approve_tools list is set via the ChannelConfig.auto_approve_tools field (useful for allowing specific tools like bash or read_file while still requiring manual approval for others).

Plan Reviews

Plan review requests are displayed as a blue embed with:

• Approve Plan (green) button — approves the plan with empty feedback
• Request Changes (gray) button — opens a modal for feedback text (up to 2000 characters)
• Feedback is forwarded through MQ as a PlanFeedbackMessage

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Configuration Reference

CLI Flag	Env Var	Default	Description
--discord-token	TURNSTONE_DISCORD_TOKEN	—	Bot token (required to enable Discord)
--discord-guild	—	0 (all guilds)	Restrict to a single Discord guild
--discord-channels	—	empty (all)	Comma-separated channel IDs to allow
--redis-host	REDIS_HOST	localhost	Redis host
--redis-port	—	6379	Redis port
--redis-password	REDIS_PASSWORD	—	Redis password
--redis-db	—	0	Redis DB number
--model	—	server default	Default model for new workstreams
--auto-approve	—	false	Auto-approve ALL tool calls (skips approval buttons entirely)
--http-host	—	127.0.0.1	HTTP server bind address for notify endpoint
--http-port	TURNSTONE_CHANNEL_PORT	8091	HTTP server port
--auth-token	TURNSTONE_CHANNEL_AUTH_TOKEN	—	Static auth token for /v1/api/notify (alternative to JWT)
--log-level	TURNSTONE_LOG_LEVEL	INFO	Log level
--log-format	TURNSTONE_LOG_FORMAT	auto	Log format (auto/json/text)

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User Identity

• The channel_users table maps (channel_type, channel_user_id) to a turnstone user_id
• Self-service linking via the /link slash command (modal input, not visible in Discord audit logs)
• Admin can force-link or unlink via the console admin panel (Admin > Channels tab). Unlinking uses a styled confirmation modal.
• Unlinked users' messages are silently dropped
• A user can be linked across multiple platforms (e.g. Discord + Slack)

See Security: Database Schema for the channel_users table definition.

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Workstream Lifecycle

1. Creation — @mention or /ask creates a Discord thread and a turnstone workstream. The ChannelRouter persists the mapping in the channel_routes table.
2. Active — messages are routed bidirectionally. The bot streams responses via message edits (updated every ~1.5 seconds).
3. Eviction — the server evicts an idle workstream for capacity. The route is preserved and the thread stays open.
4. Reactivation — the next message in the thread detects the stale route (no MQ owner), looks up the old session via get_session_id_by_ws(), and creates a new workstream with resume_session set atomically on the CreateWorkstreamMessage. The server resumes the session during creation (no separate command needed). The bridge emits a SessionResumedEvent to the channel, and the thread displays "Session resumed: {name} ({count} messages restored)". If the old session was pruned, the workstream starts fresh with no error.
5. Close — /close command closes the workstream via MQ, deletes the route, unsubscribes from events, and archives the Discord thread.

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Notifications

See also: Notification Flow diagram

The notify tool allows the LLM to proactively send notifications to users or channels on external platforms. This is useful for alerting people about task completion, errors, or important updates without waiting for them to check in.

Targeting

Two modes:

• Username — provide a turnstone username. The gateway resolves it via the channel_users table and sends to all linked channels (e.g. Discord + future Slack).
• Direct — provide channel_type + channel_id to target a specific platform channel or user DM.

Delivery Flow

Notifications bypass MQ for lower latency. The server calls the channel gateway directly over HTTP:

1. The LLM calls the notify tool with a message and target
2. _exec_notify() queries the services table for healthy channel gateways (heartbeat within the last 120 seconds)
3. The server mints a service JWT (aud: turnstone-channel) via ServiceTokenManager and POSTs to the first healthy gateway
4. The gateway validates the JWT, resolves the target, and calls adapter.send() on the appropriate platform adapter
5. On failure, the server tries the next gateway. If all fail, it retries up to 2 more times (delays: 1s, 3s), re-querying the service registry on each attempt

Service Registry

The channel gateway registers itself in the services database table on startup and sends a heartbeat every 30 seconds. On shutdown it deregisters. Services are considered stale after 120 seconds (4 missed heartbeats) and are excluded from list_services() queries.

The services table schema:

Column	Description
service_type	Service category (e.g. "channel")
service_id	Unique instance ID (channel-<hostname>-<random>)
url	HTTP base URL for the service
last_heartbeat	ISO 8601 timestamp of last heartbeat
created	ISO 8601 timestamp of initial registration

Security

• Authentication — the gateway's POST /v1/api/notify endpoint requires authentication. Configure either TURNSTONE_JWT_SECRET (the server mints JWTs with aud: turnstone-channel automatically) or a static token via --auth-token. If neither is set, the gateway fails closed and rejects all requests with 401. Server JWTs (aud: turnstone-server) are rejected.
• Rate limit — maximum 5 notifications per turn. The counter only increments on successful delivery, so failures don't consume the budget.
• SSRF protection — only http:// and https:// service URLs are allowed. Other schemes are silently skipped.
• Mention sanitization — discord.utils.escape_mentions() is applied before sending, preventing @everyone / @here abuse.
• Error redaction — generic error messages are returned to the LLM. Internal details (service IDs, URLs, exception messages) are logged server-side only.

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Adding New Adapters

The ChannelAdapter protocol defines the interface any platform adapter must implement:

class ChannelAdapter(Protocol):
    channel_type: str

    async def start(self) -> None: ...
    async def stop(self) -> None: ...
    async def send(self, channel_id: str, content: str) -> str: ...
    async def edit_message(self, channel_id: str, message_id: str, content: str) -> None: ...
    async def send_approval_request(self, channel_id: str, ws_id: str, correlation_id: str, items: list[dict]) -> None: ...
    async def send_plan_review(self, channel_id: str, ws_id: str, correlation_id: str, content: str) -> None: ...
    async def create_thread(self, parent_channel_id: str, name: str, message_id: str = "") -> str: ...

To add a new platform:

1. Create turnstone/channels/<platform>/ package
2. Implement the ChannelAdapter protocol
3. Add a --<platform>-token flag and detection logic in turnstone/channels/cli.py
4. Add the optional dependency in pyproject.toml (e.g. turnstone[slack])

See turnstone/channels/discord/ as a reference implementation.