I was fed up with receiving 5-minute voice messages on Signal just to find out someone was asking if I'm free next Tuesday. No automatic transcription, no way to quickly scan the content. You have to listen to the whole thing, often at the worst possible moment.

So I built n8n-nodes-signal-cli - an n8n extension that integrates with Signal CLI to automatically transcribe voice messages and send back a concise summary directly in the conversation.

The problem

Voice messages suck when:

• People take 5 minutes to say what could be written in 3 lines
• You're in a meeting and can't listen
• You need to find specific information buried in a long monologue
• Signal doesn't offer automatic transcription

The solution

My n8n extension adds two nodes:

• Signal CLI Trigger: fires when receiving new Signal messages
• Signal CLI: sends messages back to Signal

My workflow:

Signal message received 
    → Filter voice messages only
    → Download audio file
    → Transcribe with local Whisper (or equivalent)
    → Summarize with LLM
    → Send transcript back to Signal conversation
    

Result: That 3-minute rambling voice message becomes:

📝 Transcript: "Are you available next Tuesday at 2 PM for a meeting?"

My self-hosted n8n runs on my NAS locked behind a Zero Trust Network thanks to France nuage. 

Installation

Prerequisites:

• n8n installed and running
• signal-cli configured with your phone number

Install the extension:

npm install n8n-nodes-signal-cli

Setup:

1. Add Signal CLI credentials in n8n
2. Create new workflow
3. Add "Signal CLI Trigger" node
4. Build your processing logic
5. Use "Signal CLI" node to send messages back

Beyond transcription

This opens up tons of automation possibilities:

• Reminder bot - schedule reminders via Signal
• Auto-archiving - save important messages automatically
• Instant translation - translate messages on the fly
• Smart notifications - filter and route messages by content
• Service integration - connect Signal to Slack, Discord, etc.

Results

Since using this:

• I never miss important info hidden in long voice messages
• I can "read" voice messages anywhere, anytime
• People actually appreciate seeing their rambling transcribed concisely
• Saved tons of time not listening to minutes of audio

Check it out on GitHub. Star it if you find it useful. Report bugs. Send PRs. The usual drill.