From e3056a75630828ccff81e1c6e40cc2e2d0bb5bfd Mon Sep 17 00:00:00 2001
From: nusquama <nusquama@gmail.com>
Date: Sun, 15 Mar 2026 12:02:19 +0800
Subject: [PATCH] creation

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+AI-Powered WhatsApp Chatbot 🤖📅: Complete Booking Assistant with Gemini & Google
+
+https://n8nworkflows.xyz/workflows/ai-powered-whatsapp-chatbot-------complete-booking-assistant-with-gemini---google-13984
+
+
+# AI-Powered WhatsApp Chatbot 🤖📅: Complete Booking Assistant with Gemini & Google
+
+# 1. Workflow Overview
+
+This workflow implements an AI-powered booking assistant for a hair salon, accessible through two entry points:
+
+- **WhatsApp** for real customer conversations, supporting both **text and voice notes**
+- **n8n chat interface** for testing or embedding a chat-based version
+
+The assistant, named **Emma**, can:
+
+- identify clients
+- create or update lightweight client records in Google Sheets
+- check appointment availability in Google Calendar
+- book, reschedule, or cancel appointments
+- escalate unsupported requests through Gmail / human approval tools
+- respond in text, or in audio if the incoming WhatsApp message was audio
+
+It also includes:
+
+- a **guardrails layer** to reject unsafe or irrelevant inputs
+- **Postgres chat memory** for conversation continuity
+- a **workflow-level error handler** that emails execution errors
+
+## 1.1 Input Reception
+
+The workflow has two independent inputs:
+
+- **Chat Trigger** for direct chat messages
+- **WhatsApp Trigger** for WhatsApp messages
+
+The WhatsApp path further classifies messages into:
+- text
+- audio
+- unsupported media
+
+## 1.2 Audio Preprocessing
+
+If a WhatsApp message is audio, the workflow:
+- retrieves the media URL from WhatsApp
+- downloads the audio file
+- transcribes it with OpenAI-compatible speech-to-text
+- normalizes the transcription into the same message format used by text/chat inputs
+
+## 1.3 Input Normalization and Guardrails
+
+All supported inputs are normalized into a common structure:
+- `message`
+- `sessionId`
+- `type`
+
+The normalized content is then evaluated by a **Guardrails** node powered by Gemini. Safe inputs proceed to the AI agent; rejected content gets a fixed refusal response.
+
+## 1.4 AI Agent and Business Tools
+
+The **Virtual Assistant** agent uses Gemini plus multiple tools to perform business actions:
+
+- Google Sheets lookup for existing clients
+- Google Sheets append/update for new clients
+- Google Calendar availability lookup
+- Google Calendar create/update/delete
+- Gmail escalation
+- human-in-the-loop escalation tools
+- calculator utility
+- Postgres memory for chat context
+
+## 1.5 Response Routing
+
+After the AI agent responds, the workflow routes the output depending on channel:
+
+- **Chat input** → sends response to chat
+- **WhatsApp text input** → sends text response to WhatsApp
+- **WhatsApp audio input** → generates audio from the AI response and sends it back as WhatsApp audio
+
+## 1.6 Error Handling
+
+A dedicated **Error Trigger** catches workflow execution failures and sends an email notification through Gmail.
+
+---
+
+# 2. Block-by-Block Analysis
+
+## 2.1 Block: Chat Input Reception
+
+### Overview
+This block receives messages from the n8n chat interface and converts them into the workflow’s normalized message format. It is the non-WhatsApp entry point and is useful for testing or deploying a browser/chat-based assistant.
+
+### Nodes Involved
+- When chat message received
+- From Chat
+
+### Node Details
+
+#### When chat message received
+- **Type / role:** `@n8n/n8n-nodes-langchain.chatTrigger`  
+  Entry trigger for chat-based interactions.
+- **Configuration choices:**  
+  Configured with `responseMode: responseNodes`, meaning downstream response nodes return the reply.
+- **Key expressions or variables used:**  
+  Uses incoming `chatInput` and `sessionId`.
+- **Input / output connections:**  
+  No input; outputs to **From Chat**.
+- **Version-specific requirements:**  
+  Uses node version `1.4`.
+- **Edge cases / failures:**  
+  Chat UI integration issues, missing session IDs in custom embedding contexts.
+- **Sub-workflow reference:**  
+  None.
+
+#### From Chat
+- **Type / role:** `n8n-nodes-base.set`  
+  Maps chat trigger fields into the workflow’s standard structure.
+- **Configuration choices:**  
+  Creates:
+  - `message = {{$json.chatInput}}`
+  - `sessionId = {{$json.sessionId}}`
+- **Key expressions or variables used:**  
+  `{{$json.chatInput}}`, `{{$json.sessionId}}`
+- **Input / output connections:**  
+  Input from **When chat message received**; output to **Normalize**.
+- **Version-specific requirements:**  
+  Version `3.4`.
+- **Edge cases / failures:**  
+  Empty `chatInput`, missing `sessionId`.
+- **Sub-workflow reference:**  
+  None.
+
+---
+
+## 2.2 Block: WhatsApp Input Reception and Classification
+
+### Overview
+This block receives incoming WhatsApp messages and determines whether they are text, voice, or unsupported media. It is the main production input path for customers.
+
+### Nodes Involved
+- WhatsApp Trigger
+- Input type
+- Not supported
+
+### Node Details
+
+#### WhatsApp Trigger
+- **Type / role:** `n8n-nodes-base.whatsAppTrigger`  
+  Receives inbound WhatsApp Business messages.
+- **Configuration choices:**  
+  Listens to `messages` updates.
+- **Key expressions or variables used:**  
+  Downstream nodes read from `messages[0]`.
+- **Input / output connections:**  
+  No input; outputs to **Input type**.
+- **Version-specific requirements:**  
+  Version `1`.
+- **Edge cases / failures:**  
+  Webhook verification issues, expired/invalid WhatsApp OAuth credentials, malformed payloads, unsupported message schemas.
+- **Sub-workflow reference:**  
+  None.
+
+#### Input type
+- **Type / role:** `n8n-nodes-base.switch`  
+  Routes WhatsApp payloads by content type.
+- **Configuration choices:**  
+  Named outputs:
+  - `Text` if `messages[0].text.body` exists
+  - `Voice` if `messages[0].audio` exists
+  - fallback `extra` for unsupported content
+- **Key expressions or variables used:**  
+  - `{{$json.messages[0].text.body}}`
+  - `{{$json.messages[0].audio}}`
+- **Input / output connections:**  
+  Input from **WhatsApp Trigger**; outputs to:
+  - **Message** for text
+  - **Get Audio Url** for audio
+  - **Not supported** for everything else
+- **Version-specific requirements:**  
+  Version `3.2`.
+- **Edge cases / failures:**  
+  WhatsApp payload differences by message type, multiple messages in one webhook, fields missing unexpectedly.
+- **Sub-workflow reference:**  
+  None.
+
+#### Not supported
+- **Type / role:** `n8n-nodes-base.whatsApp`  
+  Sends a fallback message for unsupported media types.
+- **Configuration choices:**  
+  Sends fixed text:
+  “You can only send text messages, images, audio files and PDF documents.”
+- **Key expressions or variables used:**  
+  Recipient uses `{{$('WhatsApp Trigger').item.json.messages[0].from}}`
+- **Input / output connections:**  
+  Input from **Input type** fallback path; no downstream connection.
+- **Version-specific requirements:**  
+  Version `1`.
+- **Edge cases / failures:**  
+  WhatsApp send failures, invalid phone number ID, outbound permission errors.
+- **Sub-workflow reference:**  
+  None.
+
+---
+
+## 2.3 Block: WhatsApp Audio Retrieval and Transcription
+
+### Overview
+This block processes incoming voice notes by resolving the WhatsApp media URL, downloading the audio, transcribing it, and converting it into the same normalized format as text messages.
+
+### Nodes Involved
+- Get Audio Url
+- Download Audio
+- Transcribe Audio
+- Audio
+
+### Node Details
+
+#### Get Audio Url
+- **Type / role:** `n8n-nodes-base.whatsApp`  
+  Retrieves a downloadable media URL for the WhatsApp audio attachment.
+- **Configuration choices:**  
+  Resource `media`, operation `mediaUrlGet`, using the incoming audio media ID.
+- **Key expressions or variables used:**  
+  `{{$('WhatsApp Trigger').item.json.messages[0].audio.id}}`
+- **Input / output connections:**  
+  Input from **Input type** voice output; output to **Download Audio**.
+- **Version-specific requirements:**  
+  Version `1`.
+- **Edge cases / failures:**  
+  Expired media IDs, authorization errors, WhatsApp API permission issues.
+- **Sub-workflow reference:**  
+  None.
+
+#### Download Audio
+- **Type / role:** `n8n-nodes-base.httpRequest`  
+  Downloads the audio file from the media URL returned by WhatsApp.
+- **Configuration choices:**  
+  URL is dynamic from `{{$json.url}}`; authentication uses generic credential type with header auth.
+- **Key expressions or variables used:**  
+  `{{$json.url}}`
+- **Input / output connections:**  
+  Input from **Get Audio Url**; output to **Transcribe Audio**.
+- **Version-specific requirements:**  
+  Version `4.2`.
+- **Edge cases / failures:**  
+  URL expiration, wrong auth header, binary download issues, rate limits.
+- **Sub-workflow reference:**  
+  None.
+
+#### Transcribe Audio
+- **Type / role:** `@n8n/n8n-nodes-langchain.openAi`  
+  Speech-to-text transcription node.
+- **Configuration choices:**  
+  Resource `audio`, operation `transcribe`. Uses an OpenAI-compatible credential named “OpenRouter account”.
+- **Key expressions or variables used:**  
+  Consumes binary audio from previous node.
+- **Input / output connections:**  
+  Input from **Download Audio**; output to **Audio**.
+- **Version-specific requirements:**  
+  Version `1.8`. Compatibility depends on the provider actually supporting audio transcription through the configured OpenAI-compatible endpoint.
+- **Edge cases / failures:**  
+  Unsupported file format, provider incompatibility, size limits, auth failures, no binary property detected.
+- **Sub-workflow reference:**  
+  None.
+
+#### Audio
+- **Type / role:** `n8n-nodes-base.set`  
+  Standardizes transcribed audio into the same format used elsewhere.
+- **Configuration choices:**  
+  Creates:
+  - `message = {{$json.text}}`
+  - `sessionId = {{$('WhatsApp Trigger').item.json.messages[0].from}}`
+  - `type = whatsapp`
+- **Key expressions or variables used:**  
+  `{{$json.text}}`, `{{$('WhatsApp Trigger').item.json.messages[0].from}}`
+- **Input / output connections:**  
+  Input from **Transcribe Audio**; output to **Normalize**.
+- **Version-specific requirements:**  
+  Version `3.4`.
+- **Edge cases / failures:**  
+  Empty transcript, poor transcription quality, missing `text` field.
+- **Sub-workflow reference:**  
+  None.
+
+---
+
+## 2.4 Block: Text Normalization
+
+### Overview
+This block converts all supported inputs into a unified schema so that downstream AI and routing logic can operate independently of the source channel.
+
+### Nodes Involved
+- Message
+- Normalize
+
+### Node Details
+
+#### Message
+- **Type / role:** `n8n-nodes-base.set`  
+  Standardizes inbound WhatsApp text messages.
+- **Configuration choices:**  
+  Creates:
+  - `message = {{$('WhatsApp Trigger').item.json.messages[0].text.body}}`
+  - `sessionId = {{$('WhatsApp Trigger').item.json.messages[0].from}}`
+  - `type = whatsapp`
+- **Key expressions or variables used:**  
+  `{{$('WhatsApp Trigger').item.json.messages[0].text.body}}`
+- **Input / output connections:**  
+  Input from **Input type** text output; output to **Normalize**.
+- **Version-specific requirements:**  
+  Version `3.4`.
+- **Edge cases / failures:**  
+  Missing body text, schema mismatch in WhatsApp payload.
+- **Sub-workflow reference:**  
+  None.
+
+#### Normalize
+- **Type / role:** `n8n-nodes-base.set`  
+  Final normalization stage shared by both chat and WhatsApp input paths.
+- **Configuration choices:**  
+  Copies:
+  - `message = {{$json.message}}`
+  - `sessionId = {{$json.sessionId}}`
+  - `type = {{$json.type}}`
+- **Key expressions or variables used:**  
+  `{{$json.message}}`, `{{$json.sessionId}}`, `{{$json.type}}`
+- **Input / output connections:**  
+  Input from **Message**, **Audio**, or **From Chat**; output to **Guardrails**.
+- **Version-specific requirements:**  
+  Version `3.4`.
+- **Edge cases / failures:**  
+  If upstream omitted `type`, the later channel switch can fail to route correctly.
+- **Sub-workflow reference:**  
+  None.
+
+---
+
+## 2.5 Block: Guardrails and Refusal Responses
+
+### Overview
+This block screens normalized user input before it reaches the booking agent. Approved messages are sent to the AI agent; rejected ones receive a fixed refusal message through the corresponding channel.
+
+### Nodes Involved
+- Guardrails
+- Google Gemini Chat Model1
+- Send message1
+- Chat1
+
+### Node Details
+
+#### Guardrails
+- **Type / role:** `@n8n/n8n-nodes-langchain.guardrails`  
+  AI safety and relevance gate.
+- **Configuration choices:**  
+  Evaluates `{{$json.message}}`. Jailbreak detection is enabled with threshold `0.7` and customized system message support.
+- **Key expressions or variables used:**  
+  `{{$json.message}}`
+- **Input / output connections:**  
+  Input from **Normalize**.  
+  Output 0 → **Virtual Assistant**  
+  Output 1 → **Chat1**
+- **Version-specific requirements:**  
+  Version `2`.
+- **Edge cases / failures:**  
+  False positives, false negatives, model latency, credential issues with Gemini model.
+- **Sub-workflow reference:**  
+  None.
+
+#### Google Gemini Chat Model1
+- **Type / role:** `@n8n/n8n-nodes-langchain.lmChatGoogleGemini`  
+  Language model connected to the Guardrails node.
+- **Configuration choices:**  
+  Uses model `models/gemini-2.5-flash-lite`.
+- **Key expressions or variables used:**  
+  None directly in parameters beyond model selection.
+- **Input / output connections:**  
+  Connected to **Guardrails** as `ai_languageModel`.
+- **Version-specific requirements:**  
+  Version `1`.
+- **Edge cases / failures:**  
+  Gemini API quota/authentication issues, model availability changes.
+- **Sub-workflow reference:**  
+  None.
+
+#### Chat1
+- **Type / role:** `@n8n/n8n-nodes-langchain.chat`  
+  Returns a refusal response for blocked chat inputs.
+- **Configuration choices:**  
+  Fixed message: “What was communicated does not reflect our policies or is not relevant.”
+- **Key expressions or variables used:**  
+  Static text.
+- **Input / output connections:**  
+  Input from blocked branch of **Guardrails**.
+- **Version-specific requirements:**  
+  Version `1.2`.
+- **Edge cases / failures:**  
+  Only suitable for chat mode; it is not connected to WhatsApp output.
+- **Sub-workflow reference:**  
+  None.
+
+#### Send message1
+- **Type / role:** `n8n-nodes-base.whatsApp`  
+  Intended WhatsApp refusal response.
+- **Configuration choices:**  
+  Sends fixed text mirroring the refusal.
+- **Key expressions or variables used:**  
+  Recipient is `{{$('WhatsApp Trigger').item.json.messages[0].from}}`
+- **Input / output connections:**  
+  **No incoming connection in this workflow JSON.**
+- **Version-specific requirements:**  
+  Version `1`.
+- **Edge cases / failures:**  
+  As currently disconnected, it never executes. This is likely an implementation oversight.
+- **Sub-workflow reference:**  
+  None.
+
+---
+
+## 2.6 Block: AI Agent, Memory, and Business Tools
+
+### Overview
+This is the core intelligence block. The Virtual Assistant uses Gemini, memory, and multiple tools to identify the client, inspect availability, manage appointments, and escalate unsupported requests.
+
+### Nodes Involved
+- Virtual Assistant
+- Google Gemini Chat Model
+- Postgres Chat Memory
+- New client
+- Add client
+- Get events
+- Create event
+- Update event
+- Delete event
+- Calculator
+- Send Email
+- Escalation
+- Escalation1
+
+### Node Details
+
+#### Virtual Assistant
+- **Type / role:** `@n8n/n8n-nodes-langchain.agent`  
+  Main conversational agent orchestrating all business logic.
+- **Configuration choices:**  
+  Uses `{{$json.guardrailsInput}}` as input text.  
+  Includes a detailed system prompt defining:
+  - assistant identity: Emma from Cuts & Styles
+  - mandatory client identification
+  - booking/rescheduling/cancel flows
+  - date logic
+  - escalation rules
+  - salon context
+- **Key expressions or variables used:**  
+  `{{$json.guardrailsInput}}`  
+  Prompt references current date/time through `{{$now.toFormat(...)}}`.
+- **Input / output connections:**  
+  Main input from **Guardrails**; main output to **Switch**.  
+  Tool/model/memory connections:
+  - **Google Gemini Chat Model**
+  - **Postgres Chat Memory**
+  - **New client**
+  - **Add client**
+  - **Get events**
+  - **Create event**
+  - **Update event**
+  - **Delete event**
+  - **Calculator**
+  - **Escalation1**
+- **Version-specific requirements:**  
+  Version `3.1`.
+- **Edge cases / failures:**  
+  Tool misuse by model, ambiguous date interpretation, missing client details, prompt-tool mismatch, malformed tool arguments from AI.
+- **Sub-workflow reference:**  
+  None.
+
+#### Google Gemini Chat Model
+- **Type / role:** `@n8n/n8n-nodes-langchain.lmChatGoogleGemini`  
+  Primary LLM for the agent.
+- **Configuration choices:**  
+  Uses model `models/gemini-3.1-flash-lite-preview`.
+- **Key expressions or variables used:**  
+  None.
+- **Input / output connections:**  
+  Connected to **Virtual Assistant** as `ai_languageModel`.
+- **Version-specific requirements:**  
+  Version `1`.
+- **Edge cases / failures:**  
+  Preview model stability, quota issues, API auth errors.
+- **Sub-workflow reference:**  
+  None.
+
+#### Postgres Chat Memory
+- **Type / role:** `@n8n/n8n-nodes-langchain.memoryPostgresChat`  
+  Stores and retrieves chat history per session.
+- **Configuration choices:**  
+  Session key is `{{$('Normalize').item.json.sessionId}}`; custom session ID mode.
+- **Key expressions or variables used:**  
+  `{{$('Normalize').item.json.sessionId}}`
+- **Input / output connections:**  
+  Connected to **Virtual Assistant** as `ai_memory`.
+- **Version-specific requirements:**  
+  Version `1.3`.
+- **Edge cases / failures:**  
+  Database connection problems, missing schema/tables, high latency, inconsistent session keys.
+- **Sub-workflow reference:**  
+  None.
+
+#### New client
+- **Type / role:** `n8n-nodes-base.googleSheetsTool`  
+  Tool used by the agent to query the CRM sheet for existing clients.
+- **Configuration choices:**  
+  Reads from spreadsheet `Appointments`, sheet `Foglio1`. Tool description indicates row retrieval.
+- **Key expressions or variables used:**  
+  No explicit filter is preconfigured in JSON; the AI tool call is expected to provide lookup context.
+- **Input / output connections:**  
+  Connected to **Virtual Assistant** as `ai_tool`.
+- **Version-specific requirements:**  
+  Version `4.7`.
+- **Edge cases / failures:**  
+  Weak lookup specificity, sheet structure mismatches, auth issues, inefficient searches on larger sheets.
+- **Sub-workflow reference:**  
+  None.
+
+#### Add client
+- **Type / role:** `n8n-nodes-base.googleSheetsTool`  
+  Append-or-update client record in Google Sheets.
+- **Configuration choices:**  
+  Operation `appendOrUpdate`, matching column `Phone Number`.  
+  Writes:
+  - `Client` from AI
+  - `Service` from AI
+  - `Phone Number` from `{{$('Normalize').item.json.sessionId}}`
+- **Key expressions or variables used:**  
+  - `$fromAI('Client', ...)`
+  - `$fromAI('Service', ...)`
+  - `{{$('Normalize').item.json.sessionId}}`
+- **Input / output connections:**  
+  Connected to **Virtual Assistant** as `ai_tool`.
+- **Version-specific requirements:**  
+  Version `4.7`.
+- **Edge cases / failures:**  
+  Wrong phone-session mapping for non-WhatsApp chat users, missing sheet columns, auth errors.
+- **Sub-workflow reference:**  
+  None.
+
+#### Get events
+- **Type / role:** `n8n-nodes-base.googleCalendarTool`  
+  Reads calendar events to check availability and existing bookings.
+- **Configuration choices:**  
+  Operation `getAll`, return all, timezone `Europe/Madrid`, time window until 30 days from now.  
+  Tool description instructs the AI that returned data means the slot is busy.
+- **Key expressions or variables used:**  
+  `{{$now.plus({ days: 30 }).toFormat('yyyy-MM-dd')}}`
+- **Input / output connections:**  
+  Connected to **Virtual Assistant** as `ai_tool`.
+- **Version-specific requirements:**  
+  Version `1.3`.
+- **Edge cases / failures:**  
+  Timezone ambiguity, large result set, calendar auth errors, no filtering by start/min in node config beyond AI prompt guidance.
+- **Sub-workflow reference:**  
+  None.
+
+#### Create event
+- **Type / role:** `n8n-nodes-base.googleCalendarTool`  
+  Creates a calendar appointment.
+- **Configuration choices:**  
+  Calendar is fixed. AI must provide:
+  - `Start`
+  - `End`
+  - `Summary`
+  - `Description`
+  
+  Tool description tells the model to include client name and service in the event.
+- **Key expressions or variables used:**  
+  `$fromAI('Start')`, `$fromAI('End')`, `$fromAI('Summary')`, `$fromAI('Description')`
+- **Input / output connections:**  
+  Connected to **Virtual Assistant** as `ai_tool`.
+- **Version-specific requirements:**  
+  Version `1.3`.
+- **Edge cases / failures:**  
+  Invalid ISO datetimes, overlaps not prechecked, missing summary, calendar permission issues.
+- **Sub-workflow reference:**  
+  None.
+
+#### Update event
+- **Type / role:** `n8n-nodes-base.googleCalendarTool`  
+  Reschedules an existing appointment.
+- **Configuration choices:**  
+  Operation `update`. AI must supply:
+  - `Event_ID`
+  - `Start`
+  - `End`
+  
+  Tool description explicitly requires end time to be 30 minutes after start unless otherwise specified.
+- **Key expressions or variables used:**  
+  `$fromAI('Event_ID')`, `$fromAI('Start')`, `$fromAI('End')`
+- **Input / output connections:**  
+  Connected to **Virtual Assistant** as `ai_tool`.
+- **Version-specific requirements:**  
+  Version `1.3`.
+- **Edge cases / failures:**  
+  Wrong event selected, missing event ID, invalid datetime formats, race conditions if calendar changed after lookup.
+- **Sub-workflow reference:**  
+  None.
+
+#### Delete event
+- **Type / role:** `n8n-nodes-base.googleCalendarTool`  
+  Cancels an existing appointment.
+- **Configuration choices:**  
+  Operation `delete`, AI must pass `Event_ID`.
+- **Key expressions or variables used:**  
+  `$fromAI('Event_ID')`
+- **Input / output connections:**  
+  Connected to **Virtual Assistant** as `ai_tool`.
+- **Version-specific requirements:**  
+  Version `1.3`.
+- **Edge cases / failures:**  
+  Wrong event deletion, stale event ID, missing permissions.
+- **Sub-workflow reference:**  
+  None.
+
+#### Calculator
+- **Type / role:** `@n8n/n8n-nodes-langchain.toolCalculator`  
+  Utility tool for arithmetic/date-related simple reasoning support.
+- **Configuration choices:**  
+  Default configuration.
+- **Key expressions or variables used:**  
+  None.
+- **Input / output connections:**  
+  Connected to **Virtual Assistant** as `ai_tool`.
+- **Version-specific requirements:**  
+  Version `1`.
+- **Edge cases / failures:**  
+  Limited usefulness for actual calendar math versus model-native reasoning.
+- **Sub-workflow reference:**  
+  None.
+
+#### Send Email
+- **Type / role:** `n8n-nodes-base.gmailTool`  
+  Tool that emails the team when escalation is needed.
+- **Configuration choices:**  
+  Sends to `xxx@xxx.com`, subject `Escaletion`, body from AI-generated `Message`. Attribution disabled.
+- **Key expressions or variables used:**  
+  `$fromAI('Message', ...)`
+- **Input / output connections:**  
+  Connected as `ai_tool` to both **Escalation** and **Escalation1** rather than directly to the main agent.
+- **Version-specific requirements:**  
+  Version `2.2`.
+- **Edge cases / failures:**  
+  Typo in subject, invalid recipient, Gmail quota/auth errors.
+- **Sub-workflow reference:**  
+  None.
+
+#### Escalation
+- **Type / role:** `n8n-nodes-base.whatsAppHitlTool`  
+  Human-in-the-loop approval tool for WhatsApp escalation.
+- **Configuration choices:**  
+  Sends a formatted summary of the intended tool call and parameters. Approval type is `double`. Recipient phone number is expected from AI input.
+- **Key expressions or variables used:**  
+  `$tool.name`, `$tool.parameters[...]`, `$fromAI('Recipient_s_Phone_Number', ...)`
+- **Input / output connections:**  
+  Receives **Send Email** as an AI tool, but is **not connected back to Virtual Assistant**.
+- **Version-specific requirements:**  
+  Version `1.1`.
+- **Edge cases / failures:**  
+  As configured, it is effectively unused by the main agent. Also depends on correct AI-supplied phone number.
+- **Sub-workflow reference:**  
+  None.
+
+#### Escalation1
+- **Type / role:** `@n8n/n8n-nodes-langchain.chatHitlTool`  
+  Human approval tool for chat-based escalation.
+- **Configuration choices:**  
+  Sends formatted pending action details, double approval, and a maximum wait time of 45 minutes. `blockUserInput` is AI-controlled.
+- **Key expressions or variables used:**  
+  `$tool.name`, `$tool.parameters[...]`, `$fromAI('Block_User_Input', ..., 'boolean')`
+- **Input / output connections:**  
+  Connected to **Virtual Assistant** as `ai_tool`.  
+  Also connected to **Send Email** as a child tool.
+- **Version-specific requirements:**  
+  Version `1.2`.
+- **Edge cases / failures:**  
+  Approval timeout, blocked conversation if no reviewer responds, complex escalation chain.
+- **Sub-workflow reference:**  
+  None.
+
+---
+
+## 2.7 Block: Response Routing and Delivery
+
+### Overview
+This block decides whether the AI response should go back to chat, WhatsApp text, or WhatsApp audio. It preserves modality for WhatsApp audio messages by returning speech.
+
+### Nodes Involved
+- Switch
+- From audio to audio?
+- Send message
+- Generate Audio Response
+- Fix mimeType for Audio
+- Send audio
+- Chat
+
+### Node Details
+
+#### Switch
+- **Type / role:** `n8n-nodes-base.switch`  
+  Routes the AI output by normalized input channel.
+- **Configuration choices:**  
+  Output `WhatsApp` if `{{$('Normalize').item.json.type}} == whatsapp`  
+  Output `Chat` if `... == chat`
+- **Key expressions or variables used:**  
+  `{{$('Normalize').item.json.type}}`
+- **Input / output connections:**  
+  Input from **Virtual Assistant**; outputs to:
+  - **From audio to audio?** for WhatsApp
+  - **Chat** for chat
+- **Version-specific requirements:**  
+  Version `3.4`.
+- **Edge cases / failures:**  
+  Missing/incorrect `type` field results in no routing match.
+- **Sub-workflow reference:**  
+  None.
+
+#### From audio to audio?
+- **Type / role:** `n8n-nodes-base.if`  
+  Detects whether the original WhatsApp message was audio.
+- **Configuration choices:**  
+  Checks existence of `{{$('WhatsApp Trigger').item.json.messages[0].audio}}`
+- **Key expressions or variables used:**  
+  `{{$('WhatsApp Trigger').item.json.messages[0].audio}}`
+- **Input / output connections:**  
+  Input from **Switch** WhatsApp branch.  
+  True → **Generate Audio Response**  
+  False → **Send message**
+- **Version-specific requirements:**  
+  Version `2.2`.
+- **Edge cases / failures:**  
+  Because it references the trigger directly, this node is tightly coupled to WhatsApp context and would not be reusable elsewhere.
+- **Sub-workflow reference:**  
+  None.
+
+#### Send message
+- **Type / role:** `n8n-nodes-base.whatsApp`  
+  Sends plain text reply to WhatsApp.
+- **Configuration choices:**  
+  Sends `{{$json.output}}` to the sender number from the original WhatsApp message.
+- **Key expressions or variables used:**  
+  `{{$json.output}}`, `{{$('WhatsApp Trigger').item.json.messages[0].from}}`
+- **Input / output connections:**  
+  Input from **From audio to audio?** false branch.
+- **Version-specific requirements:**  
+  Version `1`.
+- **Edge cases / failures:**  
+  WhatsApp send failure, malformed text, outbound API rate limits.
+- **Sub-workflow reference:**  
+  None.
+
+#### Generate Audio Response
+- **Type / role:** `@n8n/n8n-nodes-langchain.openAi`  
+  Text-to-speech generation for WhatsApp audio replies.
+- **Configuration choices:**  
+  Resource `audio`, input is `{{$('AI Agent1').item.json.output}}`, voice `onyx`.
+- **Key expressions or variables used:**  
+  `{{$('AI Agent1').item.json.output}}`
+- **Input / output connections:**  
+  Input from **From audio to audio?** true branch; output to **Fix mimeType for Audio**.
+- **Version-specific requirements:**  
+  Version `1.8`.
+- **Edge cases / failures:**  
+  **Important issue:** expression references `AI Agent1`, but the actual agent node is named **Virtual Assistant**. As written, this expression will fail unless a node was renamed previously and the JSON is inconsistent.
+- **Sub-workflow reference:**  
+  None.
+
+#### Fix mimeType for Audio
+- **Type / role:** `n8n-nodes-base.code`  
+  Adjusts binary metadata so WhatsApp accepts the generated audio file.
+- **Configuration choices:**  
+  Iterates over all binary properties and rewrites `audio/mp3` to `audio/mpeg`.
+- **Key expressions or variables used:**  
+  JavaScript over `$input.all()`
+- **Input / output connections:**  
+  Input from **Generate Audio Response**; output to **Send audio**.
+- **Version-specific requirements:**  
+  Version `2`.
+- **Edge cases / failures:**  
+  If the TTS provider returns a different mime type or no binary data, the code may do nothing.
+- **Sub-workflow reference:**  
+  None.
+
+#### Send audio
+- **Type / role:** `n8n-nodes-base.whatsApp`  
+  Sends generated binary audio as a WhatsApp audio message.
+- **Configuration choices:**  
+  Uses `messageType: audio`, media source `useMedian8n`.
+- **Key expressions or variables used:**  
+  Recipient is `{{$('Input type').item.json.contacts[0].wa_id}}`
+- **Input / output connections:**  
+  Input from **Fix mimeType for Audio**.
+- **Version-specific requirements:**  
+  Version `1`.
+- **Edge cases / failures:**  
+  Missing binary payload, wrong recipient field, unsupported mime type.
+- **Sub-workflow reference:**  
+  None.
+
+#### Chat
+- **Type / role:** `@n8n/n8n-nodes-langchain.chat`  
+  Returns the AI reply to the chat interface.
+- **Configuration choices:**  
+  Sends `{{$json.output}}`
+- **Key expressions or variables used:**  
+  `{{$json.output}}`
+- **Input / output connections:**  
+  Input from **Switch** chat branch.
+- **Version-specific requirements:**  
+  Version `1.2`.
+- **Edge cases / failures:**  
+  Empty agent output.
+- **Sub-workflow reference:**  
+  None.
+
+---
+
+## 2.8 Block: Error Handling
+
+### Overview
+This block catches workflow execution errors globally and emails a notification with the error message and last executed node.
+
+### Nodes Involved
+- Workflow Error Handler
+- Notify: Workflow Error
+
+### Node Details
+
+#### Workflow Error Handler
+- **Type / role:** `n8n-nodes-base.errorTrigger`  
+  Starts a separate error-handling execution whenever the workflow fails.
+- **Configuration choices:**  
+  No extra parameters.
+- **Key expressions or variables used:**  
+  Downstream node uses `execution.error.message` and `execution.lastNodeExecuted`.
+- **Input / output connections:**  
+  No input; outputs to **Notify: Workflow Error**.
+- **Version-specific requirements:**  
+  Version `1`.
+- **Edge cases / failures:**  
+  Trigger only works for workflow errors, not for logically wrong but technically successful runs.
+- **Sub-workflow reference:**  
+  None.
+
+#### Notify: Workflow Error
+- **Type / role:** `n8n-nodes-base.gmail`  
+  Sends an email alert on workflow failure.
+- **Configuration choices:**  
+  Sends to `user@example.com`. HTML body includes the error message and last node.
+- **Key expressions or variables used:**  
+  - `{{$json.execution.error.message}}`
+  - `{{$json.execution.lastNodeExecuted}}`
+- **Input / output connections:**  
+  Input from **Workflow Error Handler**.
+- **Version-specific requirements:**  
+  Version `2.1`.
+- **Edge cases / failures:**  
+  Gmail auth issues. Also the subject/body still reference a different workflow (“LinkedIn PDF → JobAdder Sync”), which should be corrected.
+- **Sub-workflow reference:**  
+  None.
+
+---
+
+## 2.9 Block: Documentation / Sticky Notes
+
+### Overview
+These nodes are non-executable annotations that explain setup, steps, and external resources inside the canvas.
+
+### Nodes Involved
+- Sticky Note
+- Sticky Note1
+- Sticky Note2
+- Sticky Note3
+- Sticky Note4
+- Sticky Note5
+- Sticky Note6
+- Sticky Note7
+- Sticky Note8
+- Sticky Note9
+
+### Node Details
+All of these are `n8n-nodes-base.stickyNote` nodes. They do not affect execution, but they provide useful context:
+
+- overall workflow description and setup guidance
+- block labels for chat input, WhatsApp input, guardrails, AI agent, escalation, response sections, and error handling
+- a Google Sheets cloning link
+- a YouTube channel link
+
+They have no inputs/outputs and no runtime failure modes.
+
+---
+
+# 3. Summary Table
+
+| Node Name | Node Type | Functional Role | Input Node(s) | Output Node(s) | Sticky Note |
+|---|---|---|---|---|---|
+| Update event | n8n-nodes-base.googleCalendarTool | Update existing calendar event | — (AI tool) | Virtual Assistant (AI tool link) | ## STEP 3  - AI Agent<br>[Clone this sheet](https://docs.google.com/spreadsheets/d/1DM24yhANppmCu92D3St6GpMh2He7L2feizajN0aLDrU/edit?usp=sharing) for example of simple database |
+| Delete event | n8n-nodes-base.googleCalendarTool | Delete calendar event | — (AI tool) | Virtual Assistant (AI tool link) | ## STEP 3  - AI Agent<br>[Clone this sheet](https://docs.google.com/spreadsheets/d/1DM24yhANppmCu92D3St6GpMh2He7L2feizajN0aLDrU/edit?usp=sharing) for example of simple database |
+| Create event | n8n-nodes-base.googleCalendarTool | Create calendar event | — (AI tool) | Virtual Assistant (AI tool link) | ## STEP 3  - AI Agent<br>[Clone this sheet](https://docs.google.com/spreadsheets/d/1DM24yhANppmCu92D3St6GpMh2He7L2feizajN0aLDrU/edit?usp=sharing) for example of simple database |
+| Get events | n8n-nodes-base.googleCalendarTool | List calendar events / availability | — (AI tool) | Virtual Assistant (AI tool link) | ## STEP 3  - AI Agent<br>[Clone this sheet](https://docs.google.com/spreadsheets/d/1DM24yhANppmCu92D3St6GpMh2He7L2feizajN0aLDrU/edit?usp=sharing) for example of simple database |
+| Add client | n8n-nodes-base.googleSheetsTool | Append or update client record | — (AI tool) | Virtual Assistant (AI tool link) | ## STEP 3  - AI Agent<br>[Clone this sheet](https://docs.google.com/spreadsheets/d/1DM24yhANppmCu92D3St6GpMh2He7L2feizajN0aLDrU/edit?usp=sharing) for example of simple database |
+| Workflow Error Handler | n8n-nodes-base.errorTrigger | Trigger on workflow execution error | — | Notify: Workflow Error | ## STEP 5 - Error |
+| Notify: Workflow Error | n8n-nodes-base.gmail | Send workflow error email | Workflow Error Handler | — | ## STEP 5 - Error |
+| Virtual Assistant | @n8n/n8n-nodes-langchain.agent | Main AI booking agent | Guardrails | Switch | ## STEP 3  - AI Agent<br>[Clone this sheet](https://docs.google.com/spreadsheets/d/1DM24yhANppmCu92D3St6GpMh2He7L2feizajN0aLDrU/edit?usp=sharing) for example of simple database |
+| WhatsApp Trigger | n8n-nodes-base.whatsAppTrigger | Receive inbound WhatsApp messages | — | Input type | ## STEP 1 bis - WhatsApp Input<br>Message (text or audio with speech to text) from WhatsApp |
+| Download Audio | n8n-nodes-base.httpRequest | Download WhatsApp audio file | Get Audio Url | Transcribe Audio | ## STEP 1 bis - WhatsApp Input<br>Message (text or audio with speech to text) from WhatsApp |
+| Transcribe Audio | @n8n/n8n-nodes-langchain.openAi | Transcribe audio to text | Download Audio | Audio | ## STEP 1 bis - WhatsApp Input<br>Message (text or audio with speech to text) from WhatsApp |
+| Fix mimeType for Audio | n8n-nodes-base.code | Normalize TTS audio mime type | Generate Audio Response | Send audio | ## STEP 4 - WhatsApp Response |
+| Send message | n8n-nodes-base.whatsApp | Send WhatsApp text reply | From audio to audio? | — | ## STEP 4 - WhatsApp Response |
+| Send audio | n8n-nodes-base.whatsApp | Send WhatsApp audio reply | Fix mimeType for Audio | — | ## STEP 4 - WhatsApp Response |
+| Audio | n8n-nodes-base.set | Normalize transcribed audio input | Transcribe Audio | Normalize | ## STEP 1 bis - WhatsApp Input<br>Message (text or audio with speech to text) from WhatsApp |
+| Not supported | n8n-nodes-base.whatsApp | Send unsupported-media fallback | Input type | — | ## STEP 1 bis - WhatsApp Input<br>Message (text or audio with speech to text) from WhatsApp |
+| Get Audio Url | n8n-nodes-base.whatsApp | Resolve WhatsApp media URL | Input type | Download Audio | ## STEP 1 bis - WhatsApp Input<br>Message (text or audio with speech to text) from WhatsApp |
+| Generate Audio Response | @n8n/n8n-nodes-langchain.openAi | Generate speech from AI reply | From audio to audio? | Fix mimeType for Audio | ## STEP 4 - WhatsApp Response |
+| From audio to audio? | n8n-nodes-base.if | Decide between WhatsApp text or audio reply | Switch | Generate Audio Response, Send message | ## STEP 4 - WhatsApp Response |
+| Input type | n8n-nodes-base.switch | Classify WhatsApp message type | WhatsApp Trigger | Message, Get Audio Url, Not supported | ## STEP 1 bis - WhatsApp Input<br>Message (text or audio with speech to text) from WhatsApp |
+| Calculator | @n8n/n8n-nodes-langchain.toolCalculator | Utility calculation tool for agent | — (AI tool) | Virtual Assistant (AI tool link) | ## STEP 3  - AI Agent<br>[Clone this sheet](https://docs.google.com/spreadsheets/d/1DM24yhANppmCu92D3St6GpMh2He7L2feizajN0aLDrU/edit?usp=sharing) for example of simple database |
+| Send Email | n8n-nodes-base.gmailTool | Email escalation tool | — (AI tool via escalation tools) | Escalation, Escalation1 | ## STEP 3 bis - Escalation<br>Escalation with Chatbot or WhatsApp (select one) |
+| Escalation | n8n-nodes-base.whatsAppHitlTool | WhatsApp human-in-the-loop escalation | — | — | ## STEP 3 bis - Escalation<br>Escalation with Chatbot or WhatsApp (select one) |
+| New client | n8n-nodes-base.googleSheetsTool | Lookup client in sheet | — (AI tool) | Virtual Assistant (AI tool link) | ## STEP 3  - AI Agent<br>[Clone this sheet](https://docs.google.com/spreadsheets/d/1DM24yhANppmCu92D3St6GpMh2He7L2feizajN0aLDrU/edit?usp=sharing) for example of simple database |
+| Google Gemini Chat Model | @n8n/n8n-nodes-langchain.lmChatGoogleGemini | LLM for main agent | — | Virtual Assistant (AI language model link) | ## STEP 3  - AI Agent<br>[Clone this sheet](https://docs.google.com/spreadsheets/d/1DM24yhANppmCu92D3St6GpMh2He7L2feizajN0aLDrU/edit?usp=sharing) for example of simple database |
+| Guardrails | @n8n/n8n-nodes-langchain.guardrails | Filter unsafe / irrelevant inputs | Normalize | Virtual Assistant, Chat1 | ## STEP 2  - Guardrails |
+| Google Gemini Chat Model1 | @n8n/n8n-nodes-langchain.lmChatGoogleGemini | LLM for guardrails node | — | Guardrails (AI language model link) | ## STEP 2  - Guardrails |
+| Send message1 | n8n-nodes-base.whatsApp | WhatsApp policy refusal response | — | — | ## STEP 2  - Guardrails |
+| When chat message received | @n8n/n8n-nodes-langchain.chatTrigger | Receive chat-based input | — | From Chat | ## STEP 1 - Chat Input<br>Message from chatbot |
+| Postgres Chat Memory | @n8n/n8n-nodes-langchain.memoryPostgresChat | Conversation memory storage | — | Virtual Assistant (AI memory link) | ## STEP 3  - AI Agent<br>[Clone this sheet](https://docs.google.com/spreadsheets/d/1DM24yhANppmCu92D3St6GpMh2He7L2feizajN0aLDrU/edit?usp=sharing) for example of simple database |
+| Normalize | n8n-nodes-base.set | Standardize all supported inputs | Audio, Message, From Chat | Guardrails | ## STEP 2  - Guardrails |
+| Switch | n8n-nodes-base.switch | Route output to WhatsApp or chat | Virtual Assistant | From audio to audio?, Chat |  |
+| Escalation1 | @n8n/n8n-nodes-langchain.chatHitlTool | Chat human-in-the-loop escalation | — (AI tool) | Virtual Assistant (AI tool link) | ## STEP 3 bis - Escalation<br>Escalation with Chatbot or WhatsApp (select one) |
+| Chat | @n8n/n8n-nodes-langchain.chat | Return AI reply to chat | Switch | — | ## STEP 4 bis - Chatbot Response |
+| Chat1 | @n8n/n8n-nodes-langchain.chat | Return refusal reply to chat | Guardrails | — | ## STEP 2  - Guardrails |
+| Message | n8n-nodes-base.set | Normalize WhatsApp text input | Input type | Normalize | ## STEP 1 bis - WhatsApp Input<br>Message (text or audio with speech to text) from WhatsApp |
+| From Chat | n8n-nodes-base.set | Normalize chat trigger payload | When chat message received | Normalize | ## STEP 1 - Chat Input<br>Message from chatbot |
+| Sticky Note1 | n8n-nodes-base.stickyNote | Canvas documentation | — | — | ## STEP 1 - Chat Input<br>Message from chatbot |
+| Sticky Note2 | n8n-nodes-base.stickyNote | Canvas documentation | — | — | ## STEP 1 bis - WhatsApp Input<br>Message (text or audio with speech to text) from WhatsApp |
+| Sticky Note3 | n8n-nodes-base.stickyNote | Canvas documentation | — | — | ## STEP 2  - Guardrails |
+| Sticky Note4 | n8n-nodes-base.stickyNote | Canvas documentation | — | — | ## STEP 3  - AI Agent<br>[Clone this sheet](https://docs.google.com/spreadsheets/d/1DM24yhANppmCu92D3St6GpMh2He7L2feizajN0aLDrU/edit?usp=sharing) for example of simple database |
+| Sticky Note5 | n8n-nodes-base.stickyNote | Canvas documentation | — | — | ## STEP 3 bis - Escalation<br>Escalation with Chatbot or WhatsApp (select one) |
+| Sticky Note6 | n8n-nodes-base.stickyNote | Canvas documentation | — | — | ## STEP 4 - WhatsApp Response |
+| Sticky Note7 | n8n-nodes-base.stickyNote | Canvas documentation | — | — | ## STEP 4 bis - Chatbot Response |
+| Sticky Note8 | n8n-nodes-base.stickyNote | Canvas documentation | — | — | ## AI-Powered WhatsApp Chatbot<br>This workflow implements an **AI-powered WhatsApp booking assistant** for a hair salon. The system allows customers to **book, reschedule, or cancel appointments automatically via text or voice messages on WhatsApp**.<br><br>The workflow supports **both text and voice messages**.<br><br>### How it works<br><br>This workflow acts as an **AI-powered WhatsApp booking assistant** that processes both **text and voice messages**. Incoming messages from WhatsApp or a chat interface are captured, and voice notes are automatically downloaded and transcribed using **OpenAI Whisper**. The message then passes through a **Guardrails layer (Google Gemini)** that filters unsafe or policy-violating inputs before reaching the AI agent.<br><br>The **AI Agent (“Emma”)** interprets the user’s intent and decides which tools to call. It checks or creates clients in **Google Sheets**, manages appointments in **Google Calendar** (check availability, create, update, cancel), and escalates unsupported requests via **Gmail or human-in-the-loop channels**. Conversation history is stored in **PostgreSQL** for context. Responses are sent back through WhatsApp as **text or synthesized voice (TTS)** depending on the original message type.<br><br>### Setup steps<br><br>To deploy the workflow, configure integrations and update key resources used by the automation. First, connect required **credentials** including Google Calendar, Google Sheets, Gmail, WhatsApp Business API, OpenAI/OpenRouter for transcription and TTS, Google Gemini for AI processing and guardrails, and a **Postgres database** for conversation memory.<br><br>Next, prepare **Google Sheets** as a lightweight CRM by creating a sheet with columns such as *Phone Number*, *Client*, and *Service*, then insert its **Document ID** in the relevant nodes. Verify the correct **Google Calendar ID** for appointment management. Configure the **WhatsApp Trigger and messaging nodes** with your Phone Number ID, update the escalation **email recipient**, and review the **AI prompts** to customize salon details, assistant behavior, and guardrail thresholds before activating the workflow. |
+| Sticky Note9 | n8n-nodes-base.stickyNote | Canvas documentation | — | — | ## STEP 5 - Error |
+| Sticky Note | n8n-nodes-base.stickyNote | Canvas documentation | — | — | ## MY NEW YOUTUBE CHANNEL<br>👉 [Subscribe to my new **YouTube channel**](https://youtube.com/@n3witalia). Here I’ll share videos and Shorts with practical tutorials and **FREE templates for n8n**.<br><br>[![image](https://n3wstorage.b-cdn.net/n3witalia/youtube-n8n-cover.jpg)](https://youtube.com/@n3witalia) |
+
+---
+
+# 4. Reproducing the Workflow from Scratch
+
+1. **Create the chat entry point**
+   - Add a **Chat Trigger** node.
+   - Set response mode to **Response Nodes**.
+   - Name it **When chat message received**.
+
+2. **Create chat payload normalization**
+   - Add a **Set** node named **From Chat**.
+   - Create fields:
+     - `message` = `{{$json.chatInput}}`
+     - `sessionId` = `{{$json.sessionId}}`
+   - Connect **When chat message received → From Chat**.
+
+3. **Create the WhatsApp entry point**
+   - Add a **WhatsApp Trigger** node named **WhatsApp Trigger**.
+   - Configure it to listen to **messages** updates.
+   - Connect WhatsApp Business credentials.
+
+4. **Classify WhatsApp messages**
+   - Add a **Switch** node named **Input type**.
+   - Add output rule **Text** where `{{$json.messages[0].text.body}}` exists.
+   - Add output rule **Voice** where `{{$json.messages[0].audio}}` exists.
+   - Set fallback output to unsupported content.
+   - Connect **WhatsApp Trigger → Input type**.
+
+5. **Normalize WhatsApp text**
+   - Add a **Set** node named **Message**.
+   - Create:
+     - `message` = `{{$('WhatsApp Trigger').item.json.messages[0].text.body}}`
+     - `sessionId` = `{{$('WhatsApp Trigger').item.json.messages[0].from}}`
+     - `type` = `whatsapp`
+   - Connect **Input type (Text) → Message**.
+
+6. **Handle unsupported WhatsApp content**
+   - Add a **WhatsApp** send node named **Not supported**.
+   - Configure:
+     - operation: **send**
+     - phone number ID: your WhatsApp business sender ID
+     - recipient: `{{$('WhatsApp Trigger').item.json.messages[0].from}}`
+     - text: `You can only send text messages, images, audio files and PDF documents.`
+   - Connect **Input type (fallback) → Not supported**.
+
+7. **Retrieve audio media URL**
+   - Add a **WhatsApp** node named **Get Audio Url**.
+   - Set:
+     - resource: **media**
+     - operation: **mediaUrlGet**
+     - media ID: `{{$('WhatsApp Trigger').item.json.messages[0].audio.id}}`
+   - Connect **Input type (Voice) → Get Audio Url**.
+
+8. **Download WhatsApp audio**
+   - Add an **HTTP Request** node named **Download Audio**.
+   - URL = `{{$json.url}}`
+   - Use the appropriate header-based auth required by the WhatsApp media URL endpoint.
+   - Ensure binary download is enabled as needed by your setup.
+   - Connect **Get Audio Url → Download Audio**.
+
+9. **Transcribe audio**
+   - Add an **OpenAI / OpenAI-compatible LangChain** node named **Transcribe Audio**.
+   - Set:
+     - resource: **audio**
+     - operation: **transcribe**
+   - Attach OpenAI-compatible credentials.
+   - Connect **Download Audio → Transcribe Audio**.
+
+10. **Normalize transcribed audio**
+    - Add a **Set** node named **Audio**.
+    - Create:
+      - `message` = `{{$json.text}}`
+      - `sessionId` = `{{$('WhatsApp Trigger').item.json.messages[0].from}}`
+      - `type` = `whatsapp`
+    - Connect **Transcribe Audio → Audio**.
+
+11. **Create the shared normalization node**
+    - Add a **Set** node named **Normalize**.
+    - Create:
+      - `message` = `{{$json.message}}`
+      - `sessionId` = `{{$json.sessionId}}`
+      - `type` = `{{$json.type}}`
+    - Connect:
+      - **From Chat → Normalize**
+      - **Message → Normalize**
+      - **Audio → Normalize**
+
+12. **Add the guardrails model**
+    - Add a **Google Gemini Chat Model** node named **Google Gemini Chat Model1**.
+    - Select model `models/gemini-2.5-flash-lite`.
+    - Connect Gemini credentials.
+
+13. **Add the Guardrails node**
+    - Add a **Guardrails** node named **Guardrails**.
+    - Set text input to `{{$json.message}}`.
+    - Enable jailbreak protection.
+    - Set threshold to **0.7**.
+    - Enable custom system message if you want equivalent behavior.
+    - Connect:
+      - **Normalize → Guardrails**
+      - **Google Gemini Chat Model1 → Guardrails** as language model
+
+14. **Create blocked-response nodes**
+    - Add a **Chat** node named **Chat1** with message:
+      - `What was communicated does not reflect our policies or is not relevant.`
+    - Add a **WhatsApp** node named **Send message1** with the same text and recipient `{{$('WhatsApp Trigger').item.json.messages[0].from}}`.
+    - In the provided JSON, only **Chat1** is connected. If you want correct channel-aware refusal behavior, add a routing layer so blocked WhatsApp messages reach **Send message1** too.
+
+15. **Create the main AI model**
+    - Add a **Google Gemini Chat Model** node named **Google Gemini Chat Model**.
+    - Select model `models/gemini-3.1-flash-lite-preview`.
+
+16. **Add Postgres memory**
+    - Add a **Postgres Chat Memory** node named **Postgres Chat Memory**.
+    - Configure:
+      - session ID type: **custom key**
+      - session key: `{{$('Normalize').item.json.sessionId}}`
+    - Provide Postgres credentials and required tables/schema.
+
+17. **Create Google Sheets client lookup**
+    - Add a **Google Sheets Tool** node named **New client**.
+    - Select your spreadsheet and client sheet.
+    - Use it as a row retrieval/search tool.
+    - Spreadsheet should contain at minimum:
+      - `Phone Number`
+      - `Client`
+      - `Service`
+
+18. **Create Google Sheets client upsert**
+    - Add a **Google Sheets Tool** node named **Add client**.
+    - Operation: **appendOrUpdate**
+    - Match on column: **Phone Number**
+    - Map:
+      - `Phone Number` = `{{$('Normalize').item.json.sessionId}}`
+      - `Client` = AI-provided input
+      - `Service` = AI-provided input
+    - Use the same spreadsheet/sheet as above.
+
+19. **Create calendar lookup tool**
+    - Add a **Google Calendar Tool** node named **Get events**.
+    - Operation: **getAll**
+    - Calendar: your booking calendar
+    - Return all: enabled
+    - Timezone: `Europe/Madrid` or your local timezone
+    - `timeMax` = `{{$now.plus({ days: 30 }).toFormat('yyyy-MM-dd')}}`
+    - Add tool description explaining that existing results mean busy/unavailable slots.
+
+20. **Create calendar booking tool**
+    - Add a **Google Calendar Tool** node named **Create event**.
+    - Calendar: your booking calendar
+    - Operation: create
+    - Allow AI-provided:
+      - start
+      - end
+      - summary
+      - description
+    - Add tool description telling the model to include client name and service in the title.
+
+21. **Create calendar reschedule tool**
+    - Add a **Google Calendar Tool** node named **Update event**.
+    - Operation: update
+    - Allow AI-provided:
+      - event ID
+      - start
+      - end
+    - Add instruction that end time should be 30 minutes after start unless specified otherwise.
+
+22. **Create calendar delete tool**
+    - Add a **Google Calendar Tool** node named **Delete event**.
+    - Operation: delete
+    - Require AI-provided event ID.
+
+23. **Add calculator tool**
+    - Add a **Calculator Tool** node named **Calculator**.
+    - Default config is sufficient.
+
+24. **Create escalation email tool**
+    - Add a **Gmail Tool** node named **Send Email**.
+    - Configure:
+      - recipient: your staff email
+      - subject: escalation subject
+      - body: AI-provided message
+      - disable attribution if desired
+
+25. **Create chat human-approval escalation**
+    - Add a **Chat HITL Tool** node named **Escalation1**.
+    - Configure:
+      - approval type: **double**
+      - max wait time: **45 minutes**
+      - message body showing requested tool and parameters
+      - `blockUserInput` from AI if you want dynamic control
+    - Attach **Send Email** as an available tool to this escalation node.
+
+26. **Optionally create WhatsApp human-approval escalation**
+    - Add a **WhatsApp HITL Tool** node named **Escalation**.
+    - Configure formatted message and double approval.
+    - Recipient phone number may be AI-provided, though in practice this is brittle.
+    - Attach **Send Email** as an available tool.
+    - Note: in the provided workflow this node is not actually connected to the main agent.
+
+27. **Create the AI agent**
+    - Add an **AI Agent** node named **Virtual Assistant**.
+    - Set input text to `{{$json.guardrailsInput}}`.
+    - Add the full business system prompt defining:
+      - Emma’s identity
+      - mandatory client identification
+      - booking, rescheduling, cancellation rules
+      - escalation policy
+      - current-date logic
+      - salon details
+    - Enable retry on fail if desired.
+    - Connect:
+      - **Guardrails → Virtual Assistant**
+      - **Google Gemini Chat Model → Virtual Assistant** as language model
+      - **Postgres Chat Memory → Virtual Assistant** as memory
+      - connect all business tools as AI tools:
+        - New client
+        - Add client
+        - Get events
+        - Create event
+        - Update event
+        - Delete event
+        - Calculator
+        - Escalation1
+      - optionally connect **Escalation** too if you want WhatsApp HITL escalation
+
+28. **Create output channel router**
+    - Add a **Switch** node named **Switch**.
+    - Route by `{{$('Normalize').item.json.type}}`
+      - `whatsapp`
+      - `chat`
+    - Connect **Virtual Assistant → Switch**.
+
+29. **Create chat reply**
+    - Add a **Chat** node named **Chat**.
+    - Message = `{{$json.output}}`
+    - Connect **Switch (Chat) → Chat**.
+
+30. **Create WhatsApp modality detector**
+    - Add an **If** node named **From audio to audio?**
+    - Condition: `{{$('WhatsApp Trigger').item.json.messages[0].audio}}` exists
+    - Connect **Switch (WhatsApp) → From audio to audio?**
+
+31. **Create WhatsApp text reply**
+    - Add a **WhatsApp** send node named **Send message**.
+    - Text = `{{$json.output}}`
+    - Recipient = `{{$('WhatsApp Trigger').item.json.messages[0].from}}`
+    - Connect **From audio to audio? false → Send message**
+
+32. **Create TTS node**
+    - Add an **OpenAI / OpenAI-compatible audio generation** node named **Generate Audio Response**.
+    - Input should be the agent output.
+    - Voice = `onyx`
+    - Resource = `audio`
+    - Connect **From audio to audio? true → Generate Audio Response**
+    - Important: use a valid expression such as `{{$('Virtual Assistant').item.json.output}}`.  
+      The JSON currently references `AI Agent1`, which does not exist.
+
+33. **Fix generated audio MIME type**
+    - Add a **Code** node named **Fix mimeType for Audio**.
+    - Use JavaScript to replace `audio/mp3` with `audio/mpeg` across binary properties.
+    - Connect **Generate Audio Response → Fix mimeType for Audio**.
+
+34. **Send WhatsApp audio reply**
+    - Add a **WhatsApp** send node named **Send audio**.
+    - Operation: send
+    - Message type: audio
+    - Media source: use n8n binary media
+    - Recipient = `{{$('Input type').item.json.contacts[0].wa_id}}`
+    - Connect **Fix mimeType for Audio → Send audio**
+
+35. **Create workflow-level error handling**
+    - Add an **Error Trigger** node named **Workflow Error Handler**.
+    - Add a **Gmail** node named **Notify: Workflow Error**.
+    - Configure recipient and HTML body using:
+      - `{{$json.execution.error.message}}`
+      - `{{$json.execution.lastNodeExecuted}}`
+    - Connect **Workflow Error Handler → Notify: Workflow Error**
+    - Update the subject/body text so it references this booking workflow, not another workflow.
+
+36. **Add credentials**
+    - Configure all required credentials:
+      - WhatsApp Trigger OAuth / WhatsApp Business API
+      - WhatsApp sending credential
+      - Google Sheets OAuth2
+      - Google Calendar OAuth2
+      - Gmail OAuth2
+      - Google Gemini / PaLM API
+      - OpenAI-compatible credential for transcription and TTS
+      - Postgres
+      - optional header-auth credential for media download
+
+37. **Prepare external resources**
+    - Google Sheet:
+      - create columns `Phone Number`, `Client`, `Service`
+    - Google Calendar:
+      - choose the calendar dedicated to appointments
+    - Postgres:
+      - ensure memory storage is ready for chat history
+    - WhatsApp:
+      - confirm inbound webhook and outbound messaging are enabled
+
+38. **Test all entry points**
+    - Test chat input with simple booking requests.
+    - Test WhatsApp text booking.
+    - Test WhatsApp audio booking.
+    - Test blocked input.
+    - Test create, reschedule, delete flows.
+    - Test escalation behavior.
+
+39. **Fix the known implementation issues before production**
+    - Connect blocked WhatsApp path to **Send message1** or a proper channel-aware refusal router.
+    - Replace `{{$('AI Agent1').item.json.output}}` with `{{$('Virtual Assistant').item.json.output}}`.
+    - Review whether **Escalation** should be connected to the main agent.
+    - Correct error email subject/body text.
+    - Replace placeholder recipient emails (`xxx@xxx.com`, `user@example.com`) with real values.
+
+---
+
+# 5. General Notes & Resources
+
+| Note Content | Context or Link |
+|---|---|
+| AI-Powered WhatsApp Chatbot: This workflow implements an AI-powered WhatsApp booking assistant for a hair salon, supporting text and voice messages, using guardrails, Google Sheets, Google Calendar, Gmail escalation, PostgreSQL memory, and WhatsApp text/TTS responses. | Canvas note |
+| Clone this sheet for example of simple database | https://docs.google.com/spreadsheets/d/1DM24yhANppmCu92D3St6GpMh2He7L2feizajN0aLDrU/edit?usp=sharing |
+| Subscribe to my new YouTube channel. Here I’ll share videos and Shorts with practical videos and free n8n templates. | https://youtube.com/@n3witalia |
+| YouTube channel banner image link included in sticky note | https://n3wstorage.b-cdn.net/n3witalia/youtube-n8n-cover.jpg |
+
+## Important implementation observations
+| Note Content | Context or Link |
+|---|---|
+| The WhatsApp guardrails refusal node `Send message1` is disconnected and will never run unless explicitly connected. | Workflow implementation note |
+| `Generate Audio Response` references `AI Agent1`, but the actual agent node is `Virtual Assistant`. This expression should be corrected. | Workflow implementation note |
+| The error email still references “LinkedIn PDF → JobAdder Sync”, which is unrelated to this workflow and should be renamed. | Workflow implementation note |
+| The `Escalation` WhatsApp HITL tool is not connected back to the main agent, while `Escalation1` is. | Workflow implementation note |
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