Signal

Connect Comis to Signal with step-by-step setup

Connect your Comis agent to Signal private and group messages. Signal supports reactions, file attachments up to 100 MB, signal-text-styles formatting, and block-streaming responses. Signal requires an external signal-cli daemon running alongside Comis.

You don’t need to understand the technical details to use this feature. The configuration examples below are copy-paste ready.

Prerequisites

• Comis installed and running (Quickstart)

• A phone number to register with Signal
• signal-cli installed and running (see Step 1)

Signal is the only adapter that requires an external daemon. Comis does not connect to Signal directly — it communicates with a locally-running signal-cli REST API. You must install and register signal-cli before enabling the Signal adapter.

Setup

1. Install and register signal-cli

   Install signal-cli from the official repository. Follow the installation instructions for your platform.

   Register your phone number:

   signal-cli -u [phone] register
   

   Verify with the code sent to your phone:

   signal-cli -u [phone] verify CODE
   

   Start the signal-cli HTTP daemon:

   signal-cli -u [phone] daemon --http :8080
   

   The Comis Signal adapter talks to signal-cli over HTTP at this address. If you prefer a containerised setup, the signal-cli-rest-api Docker image exposes a compatible HTTP endpoint on port 8080.

   Verify the daemon is running:

   curl http://127.0.0.1:8080/v1/about
   

   You should get a JSON response with version information.

2. Configure Comis

   Add the Signal channel to your Comis configuration file (~/.comis/config.yaml):

   channels:
     signal:
       enabled: true
       baseUrl: "http://127.0.0.1:8080"
       account: "[phone]"
   

   Replace [phone] with the phone number you registered in Step 1.

   Never store API keys, tokens, or passwords directly in config.yaml. Use the .env file or Secret Manager for credential management.

3. Restart and verify

   Restart the Comis daemon to pick up the new configuration:

   comis daemon stop && comis daemon start
   

   Check the logs for a successful connection:

   comis daemon logs
   

   Look for a line containing “Signal adapter connected” or “channel-signal activated”. If you see this, the adapter is online.

   Send a Signal message to the registered phone number from another device to confirm the agent responds.

4. Keep signal-cli running

   The signal-cli daemon must stay running alongside Comis. If signal-cli stops, the Signal adapter will log connection errors and be unable to send or receive messages.

   For a production setup, consider running signal-cli as a systemd service or in a screen/tmux session to ensure it survives terminal closures and restarts automatically.

Configuration

These options go under channels.signal in your config.yaml:

Option	Type	Default	What it does
enabled	boolean	false	Turns on the Signal adapter
baseUrl	string	http://127.0.0.1:8080	URL of the signal-cli REST API daemon
account	string	(required)	Phone number registered with Signal (include country code with +)
cliPath	string	(optional)	Path to the signal-cli binary for auto-spawn mode. When set, Comis starts signal-cli automatically instead of requiring a separate daemon.
allowFrom	string[]	[] (all)	Restrict to specific Signal phone numbers. Empty means all contacts can talk to the bot.
mediaProcessing.transcribeAudio	boolean	true	Transcribe voice messages to text before passing to the agent
mediaProcessing.analyzeImages	boolean	true	Describe images sent to the bot using AI vision
mediaProcessing.describeVideos	boolean	true	Extract descriptions from video content
mediaProcessing.extractDocuments	boolean	true	Extract text from PDFs, DOCX, and other documents
mediaProcessing.understandLinks	boolean	true	Fetch and summarize URLs included in messages

What your agent can do

Once connected to Signal, your agent can:

• Send and delete messages (Signal supports remote-delete; edit is not available in the Signal protocol)
• React to messages with Unicode emoji
• Send file attachments up to 100 MB
• Send native voice messages (audio attachments uploaded as Signal voice notes via signal-cli)
• Receive native Signal read receipts — the agent sees when its messages have been read on the recipient’s device
• Use signal-text-styles formatting (bold, italic, monospace, strikethrough, spoiler)
• Stream responses as separate message blocks (updates every 500 ms)

Signal does not support editing messages, threads, typing indicators, fetching message history, buttons, cards/embeds, native polls, or mentions.

Platform limits

Limit	Value	What Comis does about it
Message length	65,536 characters	Rarely hit; automatically splits if exceeded
Attachment size	100 MB	Files over 100 MB are rejected with a user-friendly error message

Troubleshooting

Connection refused to localhost:8080

What happened: The signal-cli daemon is not running or is listening on a different port.

How to fix it: Start signal-cli with signal-cli -u YOUR_NUMBER daemon --http :8080 and verify it responds at http://127.0.0.1:8080/v1/about. If you changed the port, update baseUrl in your Comis config to match.

Signal adapter connects but no messages arrive

What happened: The account in your config does not match the phone number registered with signal-cli.

How to fix it: Make sure the account field includes the country code with + (e.g. "[phone]") and matches exactly what you used during signal-cli register.

Registration failed

What happened: Signal may require CAPTCHA verification for new registrations, especially from servers or cloud instances.

How to fix it: Follow the signal-cli CAPTCHA documentation for CAPTCHA-assisted registration. You may need to solve a CAPTCHA challenge in a browser and pass the token to signal-cli.

Delivery Infrastructure

How streaming, typing indicators, and retry logic work under the hood.

Multiple users & teams

Run one install for a whole team - private per person, isolated per agent.

All Channels

Compare all 9 supported platforms side by side.

Agent Configuration

Set up your agent’s personality, tools, and behavior.

Secret Management

Learn how to manage API keys and tokens securely.