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Channels

Zeph supports six I/O channels. Each implements the Channel trait and can be selected at runtime.

Overview

ChannelActivationStreamingConfirmation
CLIDefaultToken-by-token to stdouty/N prompt
DiscordZEPH_DISCORD_TOKEN (requires discord feature)Edit-in-place every 1.5sReply “yes”
SlackZEPH_SLACK_BOT_TOKEN (requires slack feature)chat.update every 2sReply “yes”
TelegramZEPH_TELEGRAM_TOKENEdit-in-place every 10sReply “yes”
TUI--tui flag (requires tui feature)Real-time in chat panelAuto-confirm
Loopback--daemon flag (requires daemon + a2a features)Via LoopbackEvent mpscAuto-confirm

CLI Channel

Default channel. Reads from stdin, writes to stdout with immediate streaming. Persistent input history (rustyline): arrow keys to navigate, prefix search, Emacs keybindings (Ctrl+A/E, Alt+B/F, Ctrl+W). History stored in SQLite across restarts.

Telegram Channel

See Run via Telegram for the setup guide. User whitelisting required (allowed_users must not be empty). MarkdownV2 formatting, voice/image support, 10s streaming throttle, 4096 char message splitting.

Discord Channel

Setup

  1. Create an application at the Discord Developer Portal
  2. Copy the bot token, select bot + applications.commands scopes
  3. Configure:
ZEPH_DISCORD_TOKEN="..." ZEPH_DISCORD_APP_ID="..." zeph

[discord]
allowed_user_ids = []
allowed_role_ids = []
allowed_channel_ids = []

When all allowlists are empty, the bot accepts messages from all users.

Slash Commands

CommandDescription
/ask <message>Send a message to the agent
/clearReset conversation context

Streaming: 1.5s throttle, messages split at 2000 chars.

Slack Channel

Setup

  1. Create a Slack app at api.slack.com/apps
  2. Add chat:write scope, install to workspace, copy Bot User OAuth Token
  3. Copy Signing Secret from Basic Information
  4. Enable Event Subscriptions, set URL to http://<host>:<port>/slack/events
  5. Subscribe to message.channels and message.im bot events
ZEPH_SLACK_BOT_TOKEN="xoxb-..." ZEPH_SLACK_SIGNING_SECRET="..." zeph

Security: HMAC-SHA256 signature verification, 5-minute replay protection, 256 KB body limit. Self-message filtering via auth.test at startup.

Streaming: 2s throttle via chat.update.

TUI Dashboard

Rich terminal interface based on ratatui. See TUI Dashboard for full documentation.

zeph --tui

Loopback Channel

Internal headless channel used by daemon mode. LoopbackChannel bridges the A2A TaskProcessor with the agent loop via two linked tokio mpsc pairs. The handle side (LoopbackHandle) exposes input_tx for sending user messages and output_rx for receiving LoopbackEvent variants (Chunk, Flush, FullMessage, Status, ToolOutput). Confirmations are auto-approved.

See Daemon Mode for usage.

Channel Selection Priority

  1. --daemon flag → Loopback (headless, requires daemon + a2a)
  2. --tui flag or ZEPH_TUI=true → TUI
  3. Discord config with token → Discord
  4. Slack config with bot_token → Slack
  5. ZEPH_TELEGRAM_TOKEN set → Telegram
  6. Default → CLI

Only one channel is active per session.

Message Queueing

Bounded FIFO queue (max 10 messages) handles input received during model inference. Consecutive messages within 500ms are merged. CLI is blocking (no queue). TUI shows a [+N queued] badge; press Ctrl+K to clear.

Attachments

Audio and image attachments are supported on Telegram, Slack, CLI/TUI (via /image). See Audio & Vision.