lettabot/docs/configuration.md

Configuration Reference

Complete reference for LettaBot configuration options.

Config File Locations

LettaBot checks these locations in order:

1. LETTABOT_CONFIG env var - Explicit path override
2. ./lettabot.yaml - Project-local (recommended)
3. ./lettabot.yml - Project-local alternate
4. ~/.lettabot/config.yaml - User global
5. ~/.lettabot/config.yml - User global alternate

For global installs (npm install -g), either:

• Create ~/.lettabot/config.yaml, or
• Set export LETTABOT_CONFIG=/path/to/your/config.yaml

Example Configuration

# Server connection
server:
  mode: cloud                    # 'cloud' or 'selfhosted'
  apiKey: letta_...              # Required for cloud mode

# Agent settings (single agent mode)
# For multiple agents, use `agents:` array instead -- see Multi-Agent section
agent:
  name: LettaBot
  model: claude-sonnet-4
  # id: agent-...                # Optional: use existing agent

# Channel configurations
channels:
  telegram:
    enabled: true
    token: "123456:ABC-DEF..."
    dmPolicy: pairing

  slack:
    enabled: true
    botToken: xoxb-...
    appToken: xapp-...
    dmPolicy: pairing

  discord:
    enabled: true
    token: "..."
    dmPolicy: pairing

  whatsapp:
    enabled: true
    selfChat: true               # IMPORTANT: true for personal numbers
    dmPolicy: pairing

  signal:
    enabled: true
    phone: "+1234567890"
    selfChat: true
    dmPolicy: pairing

# Features
features:
  cron: true
  heartbeat:
    enabled: true
    intervalMin: 60

# Polling (background checks for Gmail, etc.)
polling:
  enabled: true
  intervalMs: 60000              # Check every 60 seconds
  gmail:
    enabled: true
    account: user@example.com

# Voice transcription
transcription:
  provider: openai
  apiKey: sk-...                 # Optional: falls back to OPENAI_API_KEY
  model: whisper-1

# Attachment handling
attachments:
  maxMB: 20
  maxAgeDays: 14

# API server (health checks, CLI messaging)
api:
  port: 8080                     # Default: 8080 (or PORT env var)
  # host: 0.0.0.0               # Uncomment for Docker/Railway
  # corsOrigin: https://my.app   # Uncomment for cross-origin access

Server Configuration

Option	Type	Description
server.mode	'cloud' | 'selfhosted'	Connection mode
server.apiKey	string	API key for Letta Cloud
server.baseUrl	string	URL for self-hosted server (e.g., http://localhost:8283)

Self-Hosted Mode

server:
  mode: selfhosted
  baseUrl: http://localhost:8283

Run Letta server with Docker:

docker run -v ~/.letta/.persist/pgdata:/var/lib/postgresql/data \
  -p 8283:8283 \
  -e OPENAI_API_KEY="..." \
  letta/letta:latest

Agent Configuration (Single Agent)

The default config uses agent: and channels: at the top level for a single agent:

Option	Type	Description
agent.id	string	Use existing agent (skips creation)
agent.name	string	Name for new agent
agent.model	string	Model ID (e.g., claude-sonnet-4)

For multiple agents, see Multi-Agent Configuration below.

Multi-Agent Configuration

Run multiple independent agents from a single LettaBot instance. Each agent gets its own channels, state, cron, heartbeat, and polling services.

Use the agents: array instead of the top-level agent: and channels: keys:

server:
  mode: cloud
  apiKey: letta_...

agents:
  - name: work-assistant
    model: claude-sonnet-4
    # id: agent-abc123           # Optional: use existing agent
    channels:
      telegram:
        token: ${WORK_TELEGRAM_TOKEN}
        dmPolicy: pairing
      slack:
        botToken: ${SLACK_BOT_TOKEN}
        appToken: ${SLACK_APP_TOKEN}
    features:
      cron: true
      heartbeat:
        enabled: true
        intervalMin: 30

  - name: personal-assistant
    model: claude-sonnet-4
    channels:
      signal:
        phone: "+1234567890"
        selfChat: true
      whatsapp:
        enabled: true
        selfChat: true
    features:
      heartbeat:
        enabled: true
        intervalMin: 60

Per-Agent Options

Each entry in agents: accepts:

Option	Type	Required	Description
name	string	Yes	Agent name (used for display, creation, and state isolation)
id	string	No	Use existing agent ID (skips creation)
model	string	No	Model for agent creation
channels	object	No	Channel configs (same schema as top-level channels:). At least one agent must have channels.
features	object	No	Per-agent features (cron, heartbeat, maxToolCalls)
polling	object	No	Per-agent polling config (Gmail, etc.)
integrations	object	No	Per-agent integrations (Google, etc.)

How it works

• Each agent is a separate Letta agent with its own conversation history and memory
• Agents have isolated state, channels, and services (see known limitations for exceptions)
• The LettaGateway orchestrates startup, shutdown, and message delivery across agents
• Legacy single-agent configs (agent: + channels:) continue to work unchanged

Migrating from single to multi-agent

Your existing config:

agent:
  name: MyBot
channels:
  telegram:
    token: "..."
features:
  cron: true

Becomes:

agents:
  - name: MyBot
    channels:
      telegram:
        token: "..."
    features:
      cron: true

The server:, transcription:, attachments:, and api: sections remain at the top level (shared across all agents).

Known limitations

• Two agents cannot share the same channel type without ambiguous API routing (#219)
• WhatsApp/Signal session paths are not yet agent-scoped (#220)
• Heartbeat prompt and target are not yet configurable per-agent (#221)

Channel Configuration

All channels share these common options:

Option	Type	Description
enabled	boolean	Enable this channel
dmPolicy	'pairing' | 'allowlist' | 'open'	Access control mode
allowedUsers	string[]	User IDs/numbers for allowlist mode

DM Policies

Note: For WhatsApp/Signal with selfChat: true (personal number), dmPolicy is ignored - only you can message via "Message Yourself" / "Note to Self".

For dedicated bot numbers (selfChat: false), onboarding defaults to allowlist:

• allowlist (default for dedicated numbers): Only specified phone numbers can message
• pairing: New users get a code, approve with lettabot pairing approve
• open: Anyone can message (not recommended)

Channel-Specific Options

Telegram

Option	Type	Description
token	string	Bot token from @BotFather

Slack

Option	Type	Description
botToken	string	Bot User OAuth Token (xoxb-...)
appToken	string	App-Level Token (xapp-...) for Socket Mode

Discord

Option	Type	Description
token	string	Bot token from Discord Developer Portal

WhatsApp

Option	Type	Description
selfChat	boolean	Critical: true = only "Message Yourself" works

Signal

Option	Type	Description
phone	string	Phone number with + prefix
selfChat	boolean	true = only "Note to Self" works

Features Configuration

Heartbeat

features:
  heartbeat:
    enabled: true
    intervalMin: 60    # Check every 60 minutes

Heartbeats are background tasks where the agent can review pending work.

Custom Heartbeat Prompt

You can customize what the agent is told during heartbeats. The custom text replaces the default body while keeping the silent mode envelope (time, trigger metadata, and messaging instructions).

Inline in YAML:

features:
  heartbeat:
    enabled: true
    intervalMin: 60
    prompt: "Check your todo list and work on the highest priority item."

From a file (re-read each tick, so edits take effect without restart):

features:
  heartbeat:
    enabled: true
    intervalMin: 60
    promptFile: ./prompts/heartbeat.md

Via environment variable:

HEARTBEAT_PROMPT="Review recent conversations" npm start

Precedence: prompt (inline YAML) > HEARTBEAT_PROMPT (env var) > promptFile (file) > built-in default.

Field	Type	Default	Description
features.heartbeat.prompt	string	(none)	Custom heartbeat prompt text
features.heartbeat.promptFile	string	(none)	Path to prompt file (relative to working dir)

Cron Jobs

features:
  cron: true

Enable scheduled tasks. See Cron Setup.

No-Reply (Opt-Out)

The agent can choose not to respond to a message by sending exactly:

<no-reply/>

When the bot receives this marker, it suppresses the response and nothing is sent to the channel. This is useful in group chats where the agent shouldn't reply to every message.

The agent is taught about this behavior in two places:

• System prompt: A "Choosing Not to Reply" section explains when to use it (messages not directed at the agent, simple acknowledgments, conversations between other users, etc.)
• Message envelope: Group messages include a hint reminding the agent of the <no-reply/> option. DMs do not include this hint.

The bot also handles this gracefully during streaming -- it holds back partial output while the response could still become <no-reply/>, so users never see a partial match leak through.

Polling Configuration

Background polling for integrations like Gmail. Runs independently of agent cron jobs.

polling:
  enabled: true                # Master switch (default: auto-detected from sub-configs)
  intervalMs: 60000            # Check every 60 seconds (default: 60000)
  gmail:
    enabled: true
    account: user@example.com  # Gmail account to poll

Option	Type	Default	Description
polling.enabled	boolean	auto	Master switch. Defaults to true if any sub-config is enabled
polling.intervalMs	number	60000	Polling interval in milliseconds
polling.gmail.enabled	boolean	auto	Enable Gmail polling. Auto-detected from account
polling.gmail.account	string	-	Gmail account to poll for unread messages

Legacy config path

For backward compatibility, Gmail polling can also be configured under integrations.google:

integrations:
  google:
    enabled: true
    account: user@example.com
    pollIntervalSec: 60

The top-level polling section takes priority if both are present.

Environment variable fallback

Env Variable	Polling Config Equivalent
GMAIL_ACCOUNT	polling.gmail.account
POLLING_INTERVAL_MS	polling.intervalMs
PORT	api.port
API_HOST	api.host
API_CORS_ORIGIN	api.corsOrigin

Transcription Configuration

Voice message transcription via OpenAI Whisper:

transcription:
  provider: openai
  apiKey: sk-...       # Optional: uses OPENAI_API_KEY env var
  model: whisper-1     # Default

Attachments Configuration

attachments:
  maxMB: 20           # Max file size to download (default: 20)
  maxAgeDays: 14      # Auto-delete after N days (default: 14)

Attachments are stored in /tmp/lettabot/attachments/.

API Server Configuration

The built-in API server provides health checks and CLI messaging endpoints.

api:
  port: 9090          # Default: 8080
  host: 0.0.0.0       # Default: 127.0.0.1 (localhost only)
  corsOrigin: "*"      # Default: same-origin only

Option	Type	Default	Description
api.port	number	8080	Port for the API/health server
api.host	string	127.0.0.1	Bind address. Use 0.0.0.0 for Docker/Railway
api.corsOrigin	string	(none)	CORS origin header for cross-origin access

Environment Variables

Environment variables override config file values:

Env Variable	Config Equivalent
LETTABOT_CONFIG	Path to config file (overrides search order)
LETTA_API_KEY	server.apiKey
LETTA_BASE_URL	server.baseUrl
LETTA_AGENT_ID	agent.id
LETTA_AGENT_NAME	agent.name
LETTA_MODEL	agent.model
TELEGRAM_BOT_TOKEN	channels.telegram.token
TELEGRAM_DM_POLICY	channels.telegram.dmPolicy
SLACK_BOT_TOKEN	channels.slack.botToken
SLACK_APP_TOKEN	channels.slack.appToken
DISCORD_BOT_TOKEN	channels.discord.token
WHATSAPP_ENABLED	channels.whatsapp.enabled
WHATSAPP_SELF_CHAT_MODE	channels.whatsapp.selfChat
SIGNAL_PHONE_NUMBER	channels.signal.phone
OPENAI_API_KEY	transcription.apiKey
GMAIL_ACCOUNT	polling.gmail.account
POLLING_INTERVAL_MS	polling.intervalMs

See SKILL.md for complete environment variable reference.