WhatsApp RAG Agent (Text + Voice) with Weekly Google Drive Sync
One-line summary : Answers WhatsApp in under 100 words, understands voice notes, and retrieves trusted answers from your Google Drive docs (RAG) kept fresh weekly.
What this template does
- Reply to WhatsApp messages in a polite, human tone with ≤100 words.
- Understands text and voice notes : auto-downloads audio and transcribes to text.
- Retrieves answers from your knowledge base (RAG) : Google Drive docs → chunk → embed → store in Supabase → rerank with Cohere.
- Keeps short-term memory across the conversation to avoid repetition.
- Weekly doc sync from a selected Google Drive folder so non-technical staff can update content without touching n8n.
Why it matters
- Zero busywork: Update a Google Doc; the bot learns it on the next sync.
- Trustworthy answers: Responses come from your vetted docs, not random web text.
- Voice-first friendly: Handles the WhatsApp reality of “send a voice note.”
- Safer by design: Guardrails—no pricing unless in KB, no pushy sales, no medical advice.
Triggers
- WhatsApp Trigger: Receives incoming messages (text or audio).
- Google Drive Trigger (weekly): Detects new/updated files in the chosen folder for ingestion.
App credentials required
- WhatsApp Business Cloud (App ID, Token, Phone Number ID)
- OpenAI (Chat + Embeddings)
- Cohere (Rerank)
- Supabase (SUPABASE_URL, ANON_KEY)
- Google Drive (OAuth2) + target Folder ID
Suggested environment variables
WHATSAPP_APP_ID=
WHATSAPP_TOKEN=
WHATSAPP_PHONE_NUMBER_ID=
OPENAI_API_KEY=
COHERE_API_KEY=
SUPABASE_URL=
SUPABASE_ANON_KEY=
GDRIVE_FOLDER_ID=
RAG_TABLE_NAME="documents" # table to store vectors/metadata
MAX_ANSWER_WORDS=100 # guardrail for concise replies
Architecture overview
-
Answer-time lane (RAG Tool):
- Receive WhatsApp message → 2) Transcribe audio if present → 3) Maintain short-term memory → 4) Retrieve from Supabase vectors (topK) → 5) Rerank with Cohere → 6) Compose ≤100-word reply with sources → 7) Send on WhatsApp.
-
Ingest lane (Weekly Sync):
A) Detect Drive file updates → B) Download & convert (Docs → text/plain) → C) Chunk (size/overlap) → D) Embed with OpenAI → E) Upsert to Supabase with metadata & hashes.
How it works (node rundown)
| Node | Key Inputs | Key Outputs
---|---|---|---
1 | WhatsApp Trigger | Incoming message | Raw WhatsApp payload
2 | Switch (Attachment presence/type) | Payload | Route: Text or Audio
3 | HTTP Request (Audio path) | attachments[0].data_url | Audio file
4 | OpenAI – Translate/ASR | Audio file | Transcribed text
5 | Merge | Text path + Audio path | Unified text message
6 | Simple Memory | Recent turns | Short-term context
7 | OpenAI Chat Model | Prompt + message + memory | Draft answer (tool calls allowed)
8 | Supabase Vector Tool (retrieve-as-tool) | Query text, topK=10 | Candidate KB passages
9 | Cohere Reranker | Candidates | Re-ranked context
10 | Send WhatsApp Message | to, body | Reply sent
11 | Google Drive Trigger (weekly) | Folder ID, fileUpdated | Changed files
12 | Set (File Id) | id from trigger | File ref
13 | Google Drive – Download File | Id (Docs→txt) | Raw text
14 | Character Text Splitter | chunkSize=2000, overlap=300 | Chunks
15 | Default Data Loader | Binary→Document | Clean docs
16 | OpenAI Embeddings (ingest) | Chunks | Vectors
17 | Supabase Vector Store (insert) | Table: documents | Upserted KB
Notes
- The KB Tool is the combo of steps 8–9–7 at answer time (retrieve → rerank → answer).
- The Ingest lane is steps 11–17 (weekly sync of your Drive folder).
Setup (7‑minute sprint)
-
Import the workflow JSON.
-
Connect credentials: WhatsApp, OpenAI, Cohere, Supabase, Google Drive.
-
Google Drive Trigger: paste your Folder ID ; keep fileUpdated event.
-
Download File: ensure Google Docs convert to text/plain.
-
Supabase Vector Store (insert): set table name to documents (or your schema).
-
Character Text Splitter: keep chunkSize=2000, overlap=300 (balanced recall/latency).
-
Retrieve-as-tool: set topK=10 and enable reranker.
-
Send WhatsApp Message mapping:
- Recipient :
{{$("WhatsApp Trigger").item.json.messages[0].from}}
- Body :
{{$json.output}}
-
Test:
- Send a text and a voice note to your WhatsApp number → confirm concise answers.
- Drop a Google Doc into the watched folder → verify it’s chunked/embedded on the next weekly poll (or run ingest nodes once manually).
Prompt, tone & guardrails
-
System prompt:
- Be polite, human, and concise (≤
MAX_ANSWER_WORDS).
- Cite or reference only the KB content; if unknown, say so and offer to escalate.
- No prices unless present in the KB. No medical advice.
-
Temperature: start at 0.2 for factual replies.
-
Memory window: keep a short rolling buffer (e.g., last 4–6 turns).
Data model (minimum viable)
Table documents (example columns):
id (uuid)source_url (text)title (text)chunk (text)embedding (vector/float[] depending on extension)chunk_hash (text)updated_at (timestamp)
Indexes
- Unique index on
chunk_hash to dedupe
- Index on
updated_at for syncs
Observability & ops
- Log question , selected chunk ids/hashes , and final response to a DB/Sheet for QA.
- Add a low-confidence route (score threshold) → Slack/Telegram escalation to a human.
- Track latency and token usage to tune
topK and chunk sizes.
Customization
- Latency vs quality: try
topK=6–8 and chunkSize=1200 for speed.
- Languages: ASR node can be swapped for native multilingual output.
- Escalation: add channel handoff on low confidence or no KB hits.
- Sync cadence: change Drive Trigger to daily if content updates frequently.
Safety & compliance
- No medical advice. If uncertain or clinical, ask to schedule a consult or refer to the right department.
- PII: Don’t log full phone numbers in plaintext analytics; hash where possible.
- Prices & rates: Only answer if present in the KB; otherwise hand off to front desk.
Troubleshooting
- No reply sent: Ensure Send message node reads
{{$json.output}} (Agent’s response property).
- Audio path failing: Confirm
attachments[0].data_url exists and HTTP node fetches a valid file.
- KB not updating: Manually execute the ingest lane; check rows in Supabase.
- Irrelevant answers: Lower temperature to 0.2 , increase overlap to 400 , and verify Drive docs are clean and structured.
Categories & tags
- Categories: AI, Customer Support, Healthcare Ops, RAG, WhatsApp
- Tags: WhatsApp, RAG, Google Drive, Supabase, OpenAI, Cohere, Voice Notes
Pricing (rough, BYO keys)
- n8n: self-host free; n8n.cloud billed by plan.
- OpenAI, Cohere: usage-based by tokens/calls.
- Supabase: free tier + usage; vector storage billed by size.
- WhatsApp Cloud: Meta pricing per conversation.
Nodes used in workflow
WhatsApp Trigger , Switch , HTTP Request , OpenAI (ASR + Chat + Embeddings) , Merge , Simple Memory , Supabase Vector Tool (retrieve) , Cohere Reranker , Google Drive Trigger , Set , Google Drive – Download , Character Text Splitter , Default Data Loader.
