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

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.