WhatsApp Support Bot with Google Drive RAG, GPT-4.1-mini and Cohere Reranking

Description

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.