Overnight Gemma Agent：以 Google Gemma 在本地生成 WhatsApp 晨間摘要

Overnight Gemma Agent: Local WhatsApp & Telegram Morning Digest with Google Gemma

This is a submission for the Hacktoberfest Open-Source AI Challenge.

What I Built

Overnight Gemma Agent is a private, 100% local morning briefing assistant for your WhatsApp group chats powered by Google Gemma (gemma2:2b).

The Problem

Every morning, developers, managers, and students wake up to dozens of notifications and 100+ unread messages in team channels and group chats. Reading through all of them takes 20+ minutes of cognitive load, and critical blockers or emergency server issues get buried under casual chit-chat.

Sending confidential company chats or private group conversations to third-party cloud LLM APIs poses huge privacy, compliance, and cost issues.

The Solution: Overnight Gemma Agent

Overnight Gemma Agent monitors selected WhatsApp or Telegram groups overnight while you sleep, collects conversations in a local SQLite database, and at your designated morning hour (e.g., 7:00 AM), runs Google Gemma locally to deliver an executive Strict Two-Line Digest:

1. Line 1 (The Vibe / Core Topic): What the group talked about overnight in under 20 words.
2. Line 2 (Action Items & Blockers): Clear, prioritized tasks, deadlines, decisions, or emergency bug fixes.

Key Features

• 🔒 Zero Data Leakage / 100% Private: Your chat logs, contacts, and group messages never leave your local machine.
• ⚡ Local Google Gemma Inference: Powered by gemma2:2b running locally via Ollama with zero API cost and ultra-low latency.
• 📱 Multi-Platform Support: Seamless integration for WhatsApp (instant QR code connection via Baileys) and Telegram.
• ⏰ Morning Scheduler: Automated delivery schedule (set your morning wake-up time).
• 🧪 Instant Mock Seed Simulator: Test group conversations and prompt engineering instantly without waiting overnight.
• 💻 Clean React + Vite Dashboard: Real-time connection status, group selector, scheduled time configuration, and interactive digest card.

Architecture & How It Works

┌─────────────────────────────────┐      ┌─────────────────────────────┐
│  WhatsApp / Adapters   │ ───► │  Local SQLite Message Store │
│   (Baileys / Bot API)  │      │     (overnight_chats.db)    │
└─────────────────────────────────┘      └──────────────┬──────────────┘
                                                        │
                                                        ▼
┌─────────────────────────────────┐      ┌─────────────────────────────┐
│      Modern React Dashboard     │ ◄─── │      Gemma 2B Pipeline      │
│  (Vite + Tailwind / Responsive) │      │  (Ollama Local API / 11434) │
└─────────────────────────────────┘      └─────────────────────────────┘

The Gemma Two-Line Extraction Prompt

In backend/src/agent/gemmaSummarizer.js, Gemma is configured with deterministic parameters (temperature: 0.2, num_predict: 90) to eliminate hallucinations and output strictly actionable morning briefings:

const prompt = `You are an overnight group chat summarizer agent.
Read the following chat transcript from the group "${groupName}" and output STRICTLY TWO LINES of plain text.
Line 1: Summarize the core discussion or vibe in under 20 words.
Line 2: List any action items, deadlines, decisions, or important links (or write "No action items." if none).
Do NOT include bullet points, bold text, labels like "Line 1:", or greetings.

Chat Transcript:
${chatTranscript}`;

How to Run Locally

1. Prerequisites

• Node.js v18+
• Ollama installed with Gemma:

  ollama pull gemma2:2b

2. Start Backend Server

cd backend
npm install
node server.js

The backend starts on http://localhost:4000.

3. Start Frontend Dashboard

cd frontend
npm install
npm run dev

Open http://localhost:5173 in your browser.

Why Open Innovation & Local Models Matter

Group chats are deeply personal and sensitive. Open-weight models like Google Gemma democratize on-device AI:

• Zero API bills: Run continuous overnight cron jobs for unlimited groups at $0 marginal cost.
• Offline Resilience: Functions even if your external internet connection drops during the night.
• Complete Data Sovereignty: Compliance-friendly for workplace internal teams.

My Agent Session

This entire agent architecture, DevRelay connection, and verification was recorded live using Google Antigravity and DevRelay:

🔗 Interactive Session Replay: View Session on DEV

Recorded with DevRelay in Google Antigravity (Gemini 3.8 Flash)