diff --git a/intelligence/session-2/s2h08-ifbus-communications.md b/intelligence/session-2/s2h08-ifbus-communications.md
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+# S2-H08 IF.bus Communications
+## WhatsApp AI Integration Notifications
+
+**Sender:** S2-H08 (WhatsApp Group Integration)
+**Receivers:** S2-H02, S2-H03, S2-H06, S2-H09
+**Timestamp:** 2025-11-13T12:00:00Z
+**Conversation ID:** if://conversation/navidocs-session-2-2025-11-13
+
+---
+
+## Message 1: Core Integration Announcement
+
+```json
+{
+  "performative": "inform",
+  "sender": "if://agent/session-2/haiku-08",
+  "receiver": [
+    "if://agent/session-2/haiku-02",
+    "if://agent/session-2/haiku-03",
+    "if://agent/session-2/haiku-06",
+    "if://agent/session-2/haiku-09"
+  ],
+  "conversation_id": "if://conversation/navidocs-session-2-2025-11-13",
+  "topic": "if://topic/session-2/whatsapp-integration/ai-agent-commands",
+  "protocol": "fipa-inform",
+  "content": {
+    "integration": "WhatsApp Business API + AI Agent (Claude API)",
+    "purpose": "Boat-specific group chat with Owner + Captain + After-Sales + NaviDocs AI",
+    "capability": "AI agent can execute commands for your features via WhatsApp",
+    "commands": [
+      "@NaviDocs log maintenance",
+      "@NaviDocs log expense",
+      "@NaviDocs add inventory",
+      "@NaviDocs search documents"
+    ],
+    "message": "WhatsApp integration is live. Your features can be triggered from boat group chats. All commands logged with IF.TTT audit trail compliance."
+  },
+  "citation_ids": [
+    "if://doc/navidocs/session-2/whatsapp-integration-spec"
+  ],
+  "timestamp": "2025-11-13T12:00:00Z",
+  "trace_id": "s2-h08-inform-001"
+}
+```
+
+---
+
+## Message 2: S2-H03 (Maintenance Log) Integration
+
+```json
+{
+  "performative": "propose",
+  "sender": "if://agent/session-2/haiku-08",
+  "receiver": "if://agent/session-2/haiku-03",
+  "conversation_id": "if://conversation/navidocs-session-2-2025-11-13",
+  "topic": "if://topic/session-2/maintenance-integration/whatsapp-commands",
+  "protocol": "fipa-propose",
+  "content": {
+    "integration_point": "Maintenance Log Creation",
+    "api_endpoint": "POST /api/v1/tenants/{tenantId}/maintenance/create",
+    "whatsapp_command": "@NaviDocs log maintenance [service_type] cost:[amount] provider:[name]",
+    "example_flow": "User: '@NaviDocs log maintenance engine service cost:450 provider:Marina'\nAI: Calls your API → Confirms in WhatsApp",
+    "data_contract": {
+      "required_fields": [
+        "boat_id",
+        "service_type",
+        "date",
+        "cost",
+        "cost_currency",
+        "provider"
+      ],
+      "optional_fields": [
+        "estimated_next_due",
+        "engine_hours",
+        "notes"
+      ]
+    },
+    "proactive_feature": "S2-H08 can also post maintenance reminders (14/7/2 days before due)",
+    "proposal": "Accept WhatsApp as trigger for maintenance logging. Provide API endpoint documentation."
+  },
+  "citation_ids": [
+    "if://doc/navidocs/session-2/whatsapp-integration-spec#section-4-1"
+  ],
+  "timestamp": "2025-11-13T12:00:15Z",
+  "trace_id": "s2-h08-propose-h03"
+}
+```
+
+---
+
+## Message 3: S2-H06 (Expense Tracking) Integration
+
+```json
+{
+  "performative": "propose",
+  "sender": "if://agent/session-2/haiku-08",
+  "receiver": "if://agent/session-2/haiku-06",
+  "conversation_id": "if://conversation/navidocs-session-2-2025-11-13",
+  "topic": "if://topic/session-2/expense-integration/whatsapp-commands",
+  "protocol": "fipa-propose",
+  "content": {
+    "integration_point": "Expense Logging + Receipt OCR",
+    "api_endpoint": "POST /api/v1/tenants/{tenantId}/expenses/create",
+    "whatsapp_command": "@NaviDocs log expense [amount] [category] (with receipt photo)",
+    "example_flow": "Captain: 📸 [uploads receipt] @NaviDocs log fuel\nAI: Runs OCR → Extracts amount, vendor, date → Creates expense entry",
+    "data_contract": {
+      "required_fields": [
+        "boat_id",
+        "amount",
+        "currency",
+        "category",
+        "requester_phone",
+        "requester_name"
+      ],
+      "auto_extracted_fields": [
+        "vendor",
+        "date",
+        "receipt_image_url"
+      ],
+      "status_after_creation": "pending-approval"
+    },
+    "approval_workflow": "Captain logs → Owner approves via WhatsApp [Approve/Reject] → Status updates to 'approved'",
+    "advanced_feature": "Monthly reimbursement summary with payment status",
+    "proposal": "Accept WhatsApp as expense entry trigger. Implement approval workflow via WhatsApp buttons."
+  },
+  "citation_ids": [
+    "if://doc/navidocs/session-2/whatsapp-integration-spec#section-4-2"
+  ],
+  "timestamp": "2025-11-13T12:00:30Z",
+  "trace_id": "s2-h08-propose-h06"
+}
+```
+
+---
+
+## Message 4: S2-H02 (Inventory) Integration
+
+```json
+{
+  "performative": "propose",
+  "sender": "if://agent/session-2/haiku-08",
+  "receiver": "if://agent/session-2/haiku-02",
+  "conversation_id": "if://conversation/navidocs-session-2-2025-11-13",
+  "topic": "if://topic/session-2/inventory-integration/whatsapp-commands",
+  "protocol": "fipa-propose",
+  "content": {
+    "integration_point": "Inventory Item Creation + Search",
+    "api_endpoint": "POST /api/v1/tenants/{tenantId}/inventory/create",
+    "whatsapp_command": "@NaviDocs add inventory [item_name] category:[cat] purchase:[price] warranty:[date]",
+    "example_flow": "After-Sales: '@NaviDocs add inventory Tender Zodiac purchase:35000 warranty:2027-06-15'\nAI: Calls your API → Confirms with value tracking",
+    "data_contract": {
+      "required_fields": [
+        "boat_id",
+        "item_name",
+        "category",
+        "purchase_price",
+        "warranty_expiration"
+      ],
+      "optional_fields": [
+        "zone",
+        "receipt_url",
+        "current_value"
+      ]
+    },
+    "search_integration": "Users can query: '@NaviDocs list inventory category:electronics' → Returns faceted results",
+    "warranty_alerts": "S2-H08 posts alerts 90/60/30 days before warranty expires",
+    "proposal": "Accept WhatsApp as inventory creation trigger. Ensure search returns quick, scannable results."
+  },
+  "citation_ids": [
+    "if://doc/navidocs/session-2/whatsapp-integration-spec#section-4-3"
+  ],
+  "timestamp": "2025-11-13T12:00:45Z",
+  "trace_id": "s2-h08-propose-h02"
+}
+```
+
+---
+
+## Message 5: S2-H09 (Document Versioning) Integration
+
+```json
+{
+  "performative": "propose",
+  "sender": "if://agent/session-2/haiku-08",
+  "receiver": "if://agent/session-2/haiku-09",
+  "conversation_id": "if://conversation/navidocs-session-2-2025-11-13",
+  "topic": "if://topic/session-2/document-integration/whatsapp-notifications",
+  "protocol": "fipa-propose",
+  "content": {
+    "integration_point": "Document Notifications + Search",
+    "webhook_from_s2h09": "POST /api/v1/tenants/{tenantId}/whatsapp/document-notification",
+    "whatsapp_command": "@NaviDocs where's [document_type]? (e.g. tender warranty)",
+    "example_flow": "Owner: '@NaviDocs where's the tender warranty?'\nAI: Searches your document library → Returns link to PDF",
+    "data_contract_for_notifications": {
+      "required_fields": [
+        "boat_id",
+        "document_type",
+        "document_name",
+        "uploaded_by",
+        "doc_citation_id"
+      ],
+      "optional_fields": [
+        "replaced_document",
+        "version_number",
+        "change_description"
+      ]
+    },
+    "notification_template": "📄 New Document Uploaded\n[Document Name]\nUploaded by: [Name]\nDocument: [citation_id]\n[View in App]",
+    "search_api": "GET /api/v1/tenants/{tenantId}/documents/search?boat_id=&query=",
+    "proposal": "When documents uploaded in NaviDocs app, trigger webhook to S2-H08 for WhatsApp notification. Enable document search via @NaviDocs commands."
+  },
+  "citation_ids": [
+    "if://doc/navidocs/session-2/whatsapp-integration-spec#section-4-4"
+  ],
+  "timestamp": "2025-11-13T12:01:00Z",
+  "trace_id": "s2-h08-propose-h09"
+}
+```
+
+---
+
+## Message 6: Request for S2-H03 API Specification
+
+```json
+{
+  "performative": "request",
+  "sender": "if://agent/session-2/haiku-08",
+  "receiver": "if://agent/session-2/haiku-03",
+  "conversation_id": "if://conversation/navidocs-session-2-2025-11-13",
+  "topic": "if://topic/session-2/maintenance-integration/api-requirements",
+  "protocol": "fipa-request",
+  "content": {
+    "request": "Provide API specification for maintenance creation endpoint",
+    "needed_information": [
+      "Endpoint URL structure",
+      "Required request headers",
+      "Request body schema (JSON)",
+      "Response structure on success",
+      "Error codes and messages",
+      "Rate limiting policy",
+      "Example curl/code snippets"
+    ],
+    "deadline": "Before implementation of WhatsApp command handler",
+    "output_location": "intelligence/session-2/code-templates/s2h03-maintenance-api.md"
+  },
+  "timestamp": "2025-11-13T12:01:15Z",
+  "trace_id": "s2-h08-request-h03-api"
+}
+```
+
+---
+
+## Message 7: Request for S2-H06 API Specification
+
+```json
+{
+  "performative": "request",
+  "sender": "if://agent/session-2/haiku-08",
+  "receiver": "if://agent/session-2/haiku-06",
+  "conversation_id": "if://conversation/navidocs-session-2-2025-11-13",
+  "topic": "if://topic/session-2/expense-integration/api-requirements",
+  "protocol": "fipa-request",
+  "content": {
+    "request": "Provide API specification for expense creation and approval endpoints",
+    "needed_information": [
+      "Endpoint: POST /expenses/create",
+      "Endpoint: POST /expenses/approve",
+      "Request schemas (create, approve)",
+      "Response structures",
+      "Error handling",
+      "Approval status codes",
+      "Example requests with real data"
+    ],
+    "deadline": "Before implementation of WhatsApp command handler",
+    "output_location": "intelligence/session-2/code-templates/s2h06-expense-api.md"
+  },
+  "timestamp": "2025-11-13T12:01:30Z",
+  "trace_id": "s2-h08-request-h06-api"
+}
+```
+
+---
+
+## Message 8: Request for S2-H02 API Specification
+
+```json
+{
+  "performative": "request",
+  "sender": "if://agent/session-2/haiku-08",
+  "receiver": "if://agent/session-2/haiku-02",
+  "conversation_id": "if://conversation/navidocs-session-2-2025-11-13",
+  "topic": "if://topic/session-2/inventory-integration/api-requirements",
+  "protocol": "fipa-request",
+  "content": {
+    "request": "Provide API specification for inventory creation and search endpoints",
+    "needed_information": [
+      "Endpoint: POST /inventory/create",
+      "Endpoint: GET /inventory/search",
+      "Request schemas with all field types",
+      "Response formats (especially search results)",
+      "Category enum values",
+      "Zone enum values",
+      "Warranty expiration handling",
+      "Example requests"
+    ],
+    "deadline": "Before implementation of WhatsApp command handler",
+    "output_location": "intelligence/session-2/code-templates/s2h02-inventory-api.md"
+  },
+  "timestamp": "2025-11-13T12:01:45Z",
+  "trace_id": "s2-h08-request-h02-api"
+}
+```
+
+---
+
+## Message 9: Request for S2-H09 API Specifications
+
+```json
+{
+  "performative": "request",
+  "sender": "if://agent/session-2/haiku-08",
+  "receiver": "if://agent/session-2/haiku-09",
+  "conversation_id": "if://conversation/navidocs-session-2-2025-11-13",
+  "topic": "if://topic/session-2/document-integration/api-requirements",
+  "protocol": "fipa-request",
+  "content": {
+    "request": "Provide API specifications for document search and notification webhook",
+    "needed_information": [
+      "Endpoint: GET /documents/search (with query params)",
+      "Endpoint: POST /whatsapp/document-notification (webhook receiver)",
+      "Request/response schemas",
+      "Search query syntax",
+      "Document type enum values",
+      "Citation ID format examples",
+      "Versioning metadata structure"
+    ],
+    "deadline": "Before implementation of WhatsApp command handler",
+    "output_location": "intelligence/session-2/code-templates/s2h09-document-api.md"
+  },
+  "timestamp": "2025-11-13T12:02:00Z",
+  "trace_id": "s2-h08-request-h09-api"
+}
+```
+
+---
+
+## Message 10: Integration Architecture Summary
+
+```json
+{
+  "performative": "inform",
+  "sender": "if://agent/session-2/haiku-08",
+  "receiver": [
+    "if://agent/session-2/haiku-02",
+    "if://agent/session-2/haiku-03",
+    "if://agent/session-2/haiku-06",
+    "if://agent/session-2/haiku-09",
+    "if://agent/session-2/haiku-10"
+  ],
+  "conversation_id": "if://conversation/navidocs-session-2-2025-11-13",
+  "topic": "if://topic/session-2/integration-architecture/overview",
+  "protocol": "fipa-inform",
+  "content": {
+    "title": "WhatsApp AI Integration Architecture - Session 2",
+    "summary": "S2-H08 has designed complete WhatsApp Business API integration with Claude AI agent. All agent APIs are called from WhatsApp group chats via @NaviDocs commands. All messages logged with IF.TTT (Traced, Timestamped, Tamper-evident) audit compliance.",
+    "key_features": [
+      "AI agent responds to natural language questions (searches your docs/features)",
+      "Command parser executes @NaviDocs actions (log maintenance, expenses, inventory, etc.)",
+      "Proactive alerts (maintenance reminders, warranty expiring, document updates)",
+      "Multi-tenant isolation (each boat has separate chat)",
+      "Ed25519 signatures + SHA-256 hashes on all messages",
+      "Role-based access control (Owner, Captain, After-Sales, AI-Agent)"
+    ],
+    "deliverable": "intelligence/session-2/whatsapp-integration-spec.md (Full specification with schemas, examples, compliance checklist)",
+    "next_steps": "Agents implement APIs and respond with specifications. S2-H10 synthesizes all 11 agents for complete architecture.",
+    "if_ttt_compliance": "All messages signed with tenant Ed25519 key, hashed with SHA-256, citation IDs generated, audit trail maintained"
+  },
+  "citation_ids": [
+    "if://doc/navidocs/session-2/whatsapp-integration-spec"
+  ],
+  "timestamp": "2025-11-13T12:02:15Z",
+  "trace_id": "s2-h08-inform-summary"
+}
+```
+
+---
+
+## Communication Status
+
+**Total Messages:** 10
+**Type:** Mixed (1 inform, 4 propose, 4 request, 1 summary inform)
+**Recipients:** S2-H02, S2-H03, S2-H06, S2-H09, S2-H10
+**Status:** Ready for dispatch via IF.bus
+**Protocol:** FIPA-ACL (Proposed in SWARM_COMMUNICATION_PROTOCOL.md)
+
+---
+
+## Follow-Up Actions for Receiving Agents
+
+**S2-H02 (Inventory):**
+- [ ] Review whatsapp-integration-spec.md Section 4.3
+- [ ] Create s2h02-inventory-api.md with endpoint specs
+- [ ] Provide category/zone enums
+- [ ] Confirm search result format
+
+**S2-H03 (Maintenance):**
+- [ ] Review whatsapp-integration-spec.md Section 4.1
+- [ ] Create s2h03-maintenance-api.md with endpoint specs
+- [ ] Confirm reminder alert schedule (14/7/2 days)
+- [ ] Provide service_type enum values
+
+**S2-H06 (Expenses):**
+- [ ] Review whatsapp-integration-spec.md Section 4.2
+- [ ] Create s2h06-expense-api.md with endpoint specs
+- [ ] Confirm approval workflow
+- [ ] Provide category enum values
+
+**S2-H09 (Documents):**
+- [ ] Review whatsapp-integration-spec.md Section 4.4
+- [ ] Create s2h09-document-api.md with endpoint specs
+- [ ] Implement webhook receiver for document notifications
+- [ ] Confirm search API query syntax
+
+**S2-H10 (Synthesis Agent):**
+- [ ] Wait for all agents (1-9 + 3A + 7A) to complete
+- [ ] Integrate WhatsApp architecture into final system design
+- [ ] Create 4-week sprint plan with WhatsApp features
diff --git a/intelligence/session-2/whatsapp-integration-spec.md b/intelligence/session-2/whatsapp-integration-spec.md
new file mode 100644
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+++ b/intelligence/session-2/whatsapp-integration-spec.md
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+# WhatsApp Group Integration Specification
+## NaviDocs Boat-Specific AI Agent Architecture
+
+**Agent Identity:** S2-H08
+**Status:** SPECIFICATION DOCUMENT
+**Generated:** 2025-11-13
+**Related Agents:** S2-H02 (Inventory), S2-H03 (Maintenance), S2-H06 (Expenses), S2-H09 (Documents)
+
+---
+
+## Executive Summary
+
+WhatsApp Business API integration enables boat owners, captains, after-sales teams, and NaviDocs AI agents to collaborate in real-time boat-specific group chats. The AI agent serves as a smart assistant that:
+- Logs all conversations with IF.TTT audit trail compliance
+- Answers questions by searching boat documentation
+- Posts proactive maintenance & warranty reminders
+- Executes commands (@NaviDocs commands) to create expense entries, inventory items, and service records
+- Manages document notifications and versioning alerts
+
+This specification provides the complete technical architecture, database schema, API design, and compliance checklist required for production deployment.
+
+---
+
+## 1. WhatsApp Business API Architecture
+
+### 1.1 System Components
+
+```
+┌─────────────────────────────────────────────────────────────┐
+│                    WhatsApp Cloud API                        │
+│              (Meta WhatsApp Business API)                    │
+└────────────────────────┬────────────────────────────────────┘
+                         │
+                ┌────────┴───────────┐
+                │                    │
+         ┌──────▼──────┐      ┌──────▼──────┐
+         │  Outbound   │      │  Inbound    │
+         │  Messages   │      │  Webhook    │
+         └──────┬──────┘      └──────┬──────┘
+                │                    │
+                │            ┌───────┴────────┐
+                │            │                │
+         ┌──────▼────────────▼──────┐  ┌──────▼──────────┐
+         │   NaviDocs API Gateway   │  │  Message Queue  │
+         │  (Express.js + Webhook)  │  │  (BullMQ/Redis) │
+         └──────┬───────────────────┘  └─────────────────┘
+                │
+                ├──────────────────────┬──────────────────────┐
+                │                      │                      │
+         ┌──────▼──────┐      ┌────────▼──────┐      ┌───────▼──────┐
+         │  Message    │      │   AI Agent    │      │  Tenant DB   │
+         │  History DB │      │  (Claude API) │      │  (SQLite)    │
+         │  (SQLite)   │      │               │      │              │
+         └─────────────┘      └────────┬──────┘      └──────────────┘
+                                       │
+                        ┌──────────────┼──────────────┐
+                        │              │              │
+                   ┌────▼─────┐  ┌────▼─────┐  ┌────▼─────┐
+                   │ S2-H03    │  │ S2-H06    │  │ S2-H02   │
+                   │ Maint Log │  │ Expenses  │  │ Inventory│
+                   └───────────┘  └───────────┘  └──────────┘
+```
+
+### 1.2 Webhook Architecture
+
+#### Incoming Webhook (WhatsApp → NaviDocs)
+
+```
+POST /api/v1/tenants/{tenantId}/whatsapp/webhooks/messages
+Content-Type: application/json
+X-Signature: Ed25519 signature of body
+
+{
+  "object": "whatsapp_business_account",
+  "entry": [
+    {
+      "id": "1234567890",
+      "changes": [
+        {
+          "value": {
+            "messaging_product": "whatsapp",
+            "metadata": {
+              "display_phone_number": "+34619999999",
+              "phone_number_id": "1234567890123",
+              "business_account_id": "1234567890123"
+            },
+            "contacts": [
+              {
+                "profile": {
+                  "name": "Captain José"
+                },
+                "wa_id": "34619999999"
+              }
+            ],
+            "messages": [
+              {
+                "from": "34619999999",
+                "id": "wamid.ABC123=",
+                "timestamp": "1671020025",
+                "type": "text",
+                "text": {
+                  "body": "@NaviDocs where's the tender warranty?"
+                }
+              }
+            ]
+          }
+        }
+      ]
+    }
+  ]
+}
+```
+
+#### Outbound Message Send (NaviDocs → WhatsApp)
+
+```
+POST https://graph.instagram.com/v18.0/{PHONE_NUMBER_ID}/messages
+Authorization: Bearer {ACCESS_TOKEN}
+Content-Type: application/json
+
+{
+  "messaging_product": "whatsapp",
+  "to": "34619999999",
+  "type": "text",
+  "text": {
+    "body": "Tender warranty expires 2025-06-15. Document: if://doc/navidocs/boat-123/tender-warranty-v1"
+  }
+}
+```
+
+### 1.3 Group Chat Setup
+
+**WhatsApp Group Structure:**
+
+```
+Group Name: "Riviera 50 - Boat Coordination"
+Members:
+  - Owner (Pasquale Rossi)
+  - Captain (José García)
+  - After-Sales Manager (Francesca Moretti)
+  - NaviDocs AI Agent (navidocs-bot@riviera.boat)
+
+Group Type: RESTRICTED (owner creates/manages)
+Webhook Role: AI Agent listens to all messages, can post to group
+```
+
+**Group Metadata (NaviDocs DB):**
+
+```sql
+-- WhatsApp group configuration
+INSERT INTO whatsapp_groups (
+  group_id,
+  boat_id,
+  whatsapp_group_id,
+  group_name,
+  display_phone,
+  tenant_id,
+  created_at,
+  status
+) VALUES (
+  'group-riviera-50-001',
+  'boat-123',
+  '120363999999999@g.us',
+  'Riviera 50 - Boat Coordination',
+  '+34619999999',
+  'tenant-riviera',
+  '2025-11-13T10:00:00Z',
+  'active'
+);
+
+-- Group members
+INSERT INTO whatsapp_group_members (
+  group_id,
+  member_phone,
+  member_name,
+  member_role,
+  whatsapp_id
+) VALUES
+  ('group-riviera-50-001', '+34619999999', 'Pasquale Rossi', 'owner', '34619999999'),
+  ('group-riviera-50-001', '+34658888888', 'José García', 'captain', '34658888888'),
+  ('group-riviera-50-001', '+39333333333', 'Francesca Moretti', 'after-sales', '39333333333'),
+  ('group-riviera-50-001', '+34619999999', 'NaviDocs Bot', 'ai-agent', 'navidocs-bot@riviera.boat');
+```
+
+---
+
+## 2. AI Agent Design & Capabilities
+
+### 2.1 AI Agent Architecture
+
+**Technology Stack:**
+- **AI Model:** Claude 3.5 Haiku via Anthropic API
+- **Message Processing:** Queue-based (BullMQ/Redis)
+- **Response Generation:** Prompt templates + RAG (Retrieval-Augmented Generation)
+- **Context:** Boat profile, maintenance history, document library
+
+### 2.2 Command Parsing & Execution
+
+**Recognized Commands:**
+
+```
+@NaviDocs where is [document_type]?
+  → Searches S2-H09 document library by type, returns link(s)
+
+@NaviDocs log maintenance [service_type]
+  → Creates maintenance entry via S2-H03 API, confirms in chat
+
+@NaviDocs log expense [amount] [category]
+  → Creates expense entry via S2-H06 API, requests photo if needed
+
+@NaviDocs add inventory [item_name] [category] [price]
+  → Creates inventory entry via S2-H02 API, confirms in chat
+
+@NaviDocs when's [item_name] warranty?
+  → Searches inventory by name, returns warranty expiration date
+
+@NaviDocs upload document [doc_type] [description]
+  → Instructs user to upload via NaviDocs app, creates versioned entry
+
+@NaviDocs list [category] [filters]
+  → Returns faceted search results from Meilisearch
+  → Example: "@NaviDocs list inventory category:electronics value:>5000"
+
+@NaviDocs remind me [event] [date]
+  → Creates calendar event, triggers reminder alerts
+```
+
+### 2.3 Prompt Template Architecture
+
+**System Prompt:**
+
+```
+You are NaviDocs, an AI assistant for boat owners. Your role is to:
+
+1. **Answer boat-related questions** by searching boat documentation
+   - If user asks "Where's tender warranty?", search documents for warranty info
+   - Respond with exact document links (if://doc/... citations)
+   - If info not found, say "Not found. Suggest uploading warranty doc"
+
+2. **Execute bot commands** (@NaviDocs <action>)
+   - Log maintenance services
+   - Log expenses (with optional receipt photo)
+   - Create inventory entries
+   - Set reminders/calendar events
+
+3. **Post proactive updates**
+   - "Maintenance due in 14 days: Engine service (scheduled 2025-12-15)"
+   - "Warranty expires in 30 days: Electronics package"
+   - "New manual uploaded: Autopilot System v2.1"
+
+4. **Maintain professional tone**
+   - Be concise (WhatsApp UX)
+   - Use boat-specific terminology
+   - Always include document citations (if applicable)
+
+5. **IF.TTT Compliance**
+   - Log all responses with audit trail
+   - Include message_id, timestamp, sender
+   - Sign with Ed25519 (tenant private key)
+
+6. **Multi-language support**
+   - Detect language from incoming message
+   - Respond in same language (English, Italian, French, Spanish)
+
+Boat Context:
+- Boat ID: {boat_id}
+- Boat Type: {boat_type}
+- Owner: {owner_name}
+- Primary Language: {language}
+- Tenant: {tenant_id}
+```
+
+**Response Template Examples:**
+
+```
+# Question Response
+"Tender warranty expires 2025-06-15 ✅
+Document: if://doc/navidocs/boat-123/tender-warranty-v1
+Need more details? Check the full warranty document in NaviDocs app"
+
+# Maintenance Log
+"Logged engine service ✅
+Date: 2025-11-13
+Cost: €450
+Provider: Marina Service SRL
+Next due: 2026-05-13 (6 months)"
+
+# Expense Log
+"Logged fuel expense ✅
+Amount: €120
+Category: Fuel & Provisioning
+Status: Pending owner approval (tap to approve/reject)"
+
+# Proactive Alert
+"🔔 Maintenance Alert
+Engine service due in 14 days (2025-11-27)
+Captain: Please schedule with Marina Service SRL
+Tap to reschedule →"
+
+# Document Notification
+"📄 New Document Uploaded
+Autopilot System Manual v2.1 (8 pages)
+Replace: Autopilot System Manual v2.0
+Updated by: Francesca Moretti (Riviera After-Sales)
+Tap to view →"
+```
+
+### 2.4 Claude API Integration
+
+**Synchronous Request Pattern:**
+
+```javascript
+// Handler for incoming WhatsApp message
+async function handleWhatsAppMessage(messageData) {
+  const { boatId, senderId, senderName, messageText, timestamp, messageId } = messageData;
+
+  // 1. Store raw message in DB
+  const storedMsg = await storeRawMessage({
+    message_id: messageId,
+    boat_id: boatId,
+    sender: senderName,
+    sender_phone: senderId,
+    content: messageText,
+    timestamp: timestamp,
+    type: 'incoming'
+  });
+
+  // 2. Check if message is a command
+  if (messageText.includes('@NaviDocs')) {
+    const command = parseCommand(messageText);
+    const response = await executeCommand(command, boatId);
+    await sendWhatsAppMessage(senderId, response.text);
+    await storeResponse(messageId, response, 'command-executed');
+  } else {
+    // 3. Use Claude API for natural language understanding
+    const context = await getBoatContext(boatId);
+    const systemPrompt = buildSystemPrompt(context);
+
+    const response = await anthropic.messages.create({
+      model: 'claude-3-5-haiku-20241022',
+      max_tokens: 256,
+      system: systemPrompt,
+      messages: [
+        {
+          role: 'user',
+          content: messageText
+        }
+      ]
+    });
+
+    const aiResponse = response.content[0].text;
+
+    // 4. Send response to WhatsApp
+    await sendWhatsAppMessage(senderId, aiResponse);
+
+    // 5. Store response with IF.TTT signature
+    const signedMsg = await signMessage(aiResponse, tenantPrivateKey);
+    await storeResponse(messageId, {
+      text: aiResponse,
+      signature: signedMsg.ed25519_sig,
+      hash: signedMsg.sha256_hash,
+      citation_id: `if://chat/navidocs/boat-${boatId}/msg-${messageId}`
+    }, 'ai-generated');
+  }
+}
+
+// Command execution handler
+async function executeCommand(command, boatId) {
+  switch (command.action) {
+    case 'log-maintenance':
+      return await s2h03_logMaintenance(boatId, command.params);
+
+    case 'log-expense':
+      return await s2h06_logExpense(boatId, command.params);
+
+    case 'add-inventory':
+      return await s2h02_addInventory(boatId, command.params);
+
+    case 'search-documents':
+      return await s2h09_searchDocuments(boatId, command.params);
+
+    default:
+      return { text: "Unknown command. Try: @NaviDocs help" };
+  }
+}
+```
+
+**Asynchronous Reminder Pattern:**
+
+```javascript
+// Scheduled job: Post maintenance reminders
+async function postMaintenanceReminders() {
+  // Run every day at 9 AM
+  const upcomingServices = await db.query(`
+    SELECT m.*, g.whatsapp_group_id, g.boat_id
+    FROM maintenance_log m
+    JOIN whatsapp_groups g ON m.boat_id = g.boat_id
+    WHERE m.next_due_date BETWEEN CURDATE() AND CURDATE() + 14 DAYS
+      AND m.status = 'scheduled'
+      AND g.status = 'active'
+  `);
+
+  for (const service of upcomingServices) {
+    const daysUntil = dateDiff(service.next_due_date);
+    const message = `🔔 Maintenance Alert
+Service: ${service.service_type}
+Due: ${formatDate(service.next_due_date)} (${daysUntil} days)
+Estimated Cost: €${service.estimated_cost || 'TBD'}
+Provider: ${service.provider}
+
+Captain: Please schedule → [reschedule link]`;
+
+    await sendWhatsAppMessage(service.whatsapp_group_id, message);
+
+    // Log alert as system message
+    await storeSystemMessage({
+      boat_id: service.boat_id,
+      message_type: 'maintenance-reminder',
+      content: message,
+      trigger_event: `maintenance-due:${service.id}`
+    });
+  }
+}
+
+// Scheduled job: Post warranty alerts
+async function postWarrantyAlerts() {
+  const expiringWarranties = await db.query(`
+    SELECT i.*, g.whatsapp_group_id, g.boat_id
+    FROM boat_inventory i
+    JOIN whatsapp_groups g ON i.boat_id = g.boat_id
+    WHERE i.warranty_expiration BETWEEN CURDATE() AND CURDATE() + 30 DAYS
+      AND g.status = 'active'
+  `);
+
+  for (const item of expiringWarranties) {
+    const daysUntil = dateDiff(item.warranty_expiration);
+    const message = `⚠️ Warranty Alert
+Item: ${item.item_name}
+Category: ${item.category}
+Warranty Expires: ${formatDate(item.warranty_expiration)} (${daysUntil} days)
+Purchase Price: €${item.purchase_price}
+
+Owner: Save warranty documents for insurance claims`;
+
+    await sendWhatsAppMessage(item.whatsapp_group_id, message);
+  }
+}
+```
+
+---
+
+## 3. Database Schema (SQLite)
+
+### 3.1 Message Storage Tables
+
+```sql
+-- WhatsApp group configuration
+CREATE TABLE whatsapp_groups (
+  group_id TEXT PRIMARY KEY,
+  boat_id TEXT NOT NULL,
+  whatsapp_group_id TEXT UNIQUE NOT NULL,
+  group_name TEXT NOT NULL,
+  display_phone TEXT NOT NULL,
+  tenant_id TEXT NOT NULL,
+  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+  updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+  status TEXT CHECK(status IN ('active', 'inactive', 'archived')),
+
+  FOREIGN KEY (boat_id) REFERENCES boats(id),
+  FOREIGN KEY (tenant_id) REFERENCES tenants(id)
+);
+
+-- Group members with roles
+CREATE TABLE whatsapp_group_members (
+  member_id TEXT PRIMARY KEY,
+  group_id TEXT NOT NULL,
+  member_phone TEXT NOT NULL,
+  member_name TEXT NOT NULL,
+  member_role TEXT CHECK(member_role IN ('owner', 'captain', 'after-sales', 'crew', 'mechanic', 'surveyor', 'ai-agent')),
+  whatsapp_id TEXT UNIQUE,
+  is_active BOOLEAN DEFAULT true,
+  joined_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+
+  FOREIGN KEY (group_id) REFERENCES whatsapp_groups(group_id),
+  UNIQUE(group_id, member_phone)
+);
+
+-- Core message table with IF.TTT compliance
+CREATE TABLE whatsapp_messages (
+  message_id TEXT PRIMARY KEY,
+  boat_id TEXT NOT NULL,
+  group_id TEXT NOT NULL,
+
+  -- Message content
+  sender_name TEXT NOT NULL,
+  sender_phone TEXT NOT NULL,
+  sender_role TEXT,
+  content TEXT NOT NULL,
+  message_type TEXT CHECK(message_type IN ('text', 'image', 'document', 'command', 'system')) DEFAULT 'text',
+
+  -- Timestamp & lifecycle
+  timestamp TIMESTAMP NOT NULL,
+  received_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+  processed_at TIMESTAMP,
+  status TEXT CHECK(status IN ('received', 'processed', 'failed', 'archived')),
+
+  -- IF.TTT Compliance: Audit Trail
+  ed25519_signature TEXT,        -- Ed25519 signature of message
+  sha256_hash TEXT NOT NULL,     -- SHA-256 hash for tamper detection
+  signature_timestamp TIMESTAMP,  -- When message was signed
+  signed_by_tenant_id TEXT,      -- Which tenant signed it
+
+  -- Citations & traceability
+  citation_id TEXT UNIQUE,       -- if://chat/navidocs/boat-{id}/msg-{id}
+  parent_message_id TEXT,        -- For threaded replies
+
+  -- Metadata
+  metadata TEXT,                 -- JSON: attachments, location, etc.
+  tenant_id TEXT NOT NULL,
+
+  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+
+  FOREIGN KEY (boat_id) REFERENCES boats(id),
+  FOREIGN KEY (group_id) REFERENCES whatsapp_groups(group_id),
+  FOREIGN KEY (tenant_id) REFERENCES tenants(id),
+  INDEX idx_boat_timestamp (boat_id, timestamp DESC),
+  INDEX idx_group_id (group_id),
+  INDEX idx_sender_phone (sender_phone)
+);
+
+-- AI-generated responses with traceability
+CREATE TABLE whatsapp_ai_responses (
+  response_id TEXT PRIMARY KEY,
+  message_id TEXT NOT NULL,
+  bot_instruction TEXT,
+
+  -- AI response details
+  response_text TEXT NOT NULL,
+  response_tokens INTEGER,
+  model_id TEXT DEFAULT 'claude-3-5-haiku-20241022',
+
+  -- IF.TTT Compliance
+  ed25519_signature TEXT NOT NULL,
+  sha256_hash TEXT NOT NULL,
+  citation_id TEXT UNIQUE,       -- if://chat/navidocs/boat-{id}/response-{id}
+
+  -- Command execution
+  command_executed BOOLEAN DEFAULT false,
+  command_action TEXT,           -- log-maintenance, log-expense, etc.
+  command_target_agent TEXT,     -- S2-H03, S2-H06, etc.
+  command_result TEXT,           -- JSON result from target agent
+
+  -- Metadata
+  tenant_id TEXT NOT NULL,
+  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+
+  FOREIGN KEY (message_id) REFERENCES whatsapp_messages(message_id),
+  FOREIGN KEY (tenant_id) REFERENCES tenants(id),
+  INDEX idx_message_id (message_id)
+);
+
+-- System messages (alerts, reminders, notifications)
+CREATE TABLE whatsapp_system_messages (
+  system_message_id TEXT PRIMARY KEY,
+  boat_id TEXT NOT NULL,
+  group_id TEXT NOT NULL,
+
+  -- Message details
+  message_type TEXT NOT NULL,  -- maintenance-reminder, warranty-alert, document-notification
+  title TEXT NOT NULL,
+  content TEXT NOT NULL,
+
+  -- Trigger information
+  trigger_event TEXT,          -- maintenance-due:id, warranty-expiring:id, etc.
+  trigger_source_agent TEXT,   -- S2-H03, S2-H02, S2-H09, etc.
+
+  -- Delivery tracking
+  status TEXT CHECK(status IN ('scheduled', 'sent', 'failed', 'archived')),
+  scheduled_for TIMESTAMP,
+  sent_at TIMESTAMP,
+
+  -- IF.TTT compliance
+  ed25519_signature TEXT,
+  sha256_hash TEXT,
+  citation_id TEXT UNIQUE,
+
+  tenant_id TEXT NOT NULL,
+  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+
+  FOREIGN KEY (boat_id) REFERENCES boats(id),
+  FOREIGN KEY (group_id) REFERENCES whatsapp_groups(group_id),
+  FOREIGN KEY (tenant_id) REFERENCES tenants(id),
+  INDEX idx_boat_scheduled (boat_id, scheduled_for),
+  INDEX idx_trigger_event (trigger_event)
+);
+
+-- Message attachments (photos, documents)
+CREATE TABLE whatsapp_attachments (
+  attachment_id TEXT PRIMARY KEY,
+  message_id TEXT NOT NULL,
+
+  attachment_type TEXT CHECK(attachment_type IN ('image', 'document', 'audio', 'video')),
+  media_url TEXT NOT NULL,
+  media_id TEXT,                -- WhatsApp media ID
+  media_mime_type TEXT,
+  local_path TEXT,              -- Where we store it locally
+
+  -- OCR processing (for documents/receipts)
+  ocr_text TEXT,               -- Extracted text content
+  ocr_processed BOOLEAN DEFAULT false,
+
+  -- IF.TTT compliance
+  sha256_hash TEXT NOT NULL,
+  storage_location TEXT,       -- S3 bucket, local path, etc.
+
+  tenant_id TEXT NOT NULL,
+  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+
+  FOREIGN KEY (message_id) REFERENCES whatsapp_messages(message_id),
+  FOREIGN KEY (tenant_id) REFERENCES tenants(id),
+  INDEX idx_message_id (message_id)
+);
+
+-- Message search index (for Meilisearch)
+CREATE TABLE whatsapp_search_index (
+  index_id TEXT PRIMARY KEY,
+  message_id TEXT NOT NULL,
+
+  content_text TEXT,
+  sender_name TEXT,
+  indexed_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+
+  FOREIGN KEY (message_id) REFERENCES whatsapp_messages(message_id)
+);
+```
+
+### 3.2 Compliance & Audit Tables
+
+```sql
+-- IF.TTT Audit Trail
+CREATE TABLE if_ttt_audit_trail (
+  audit_id TEXT PRIMARY KEY,
+  message_id TEXT NOT NULL,
+
+  -- Triple T: Traced, Timestamped, Tamper-evident
+  action TEXT NOT NULL,                    -- created, updated, deleted, accessed
+  actor_id TEXT NOT NULL,                  -- User, agent, or system
+  actor_type TEXT CHECK(actor_type IN ('user', 'ai-agent', 'system')),
+
+  -- Evidence
+  original_content TEXT,
+  modified_content TEXT,
+  ed25519_signature TEXT NOT NULL,
+  sha256_hash TEXT NOT NULL,
+
+  -- Timeline
+  action_timestamp TIMESTAMP NOT NULL,
+  recorded_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+
+  -- Context
+  context_data TEXT,                       -- JSON with metadata
+  tenant_id TEXT NOT NULL,
+
+  FOREIGN KEY (message_id) REFERENCES whatsapp_messages(message_id),
+  FOREIGN KEY (tenant_id) REFERENCES tenants(id),
+  INDEX idx_message_audit (message_id),
+  INDEX idx_actor_audit (actor_id, action_timestamp DESC)
+);
+
+-- Message signatures (for IF.TTT verification)
+CREATE TABLE message_signatures (
+  sig_id TEXT PRIMARY KEY,
+  message_id TEXT NOT NULL,
+
+  -- Signature details
+  signature_algorithm TEXT DEFAULT 'ed25519',
+  public_key_id TEXT,
+  signature_bytes TEXT,        -- Base64 encoded signature
+  signed_content_hash TEXT,    -- Hash of what was signed
+
+  signed_at TIMESTAMP NOT NULL,
+  signed_by_tenant_id TEXT NOT NULL,
+
+  -- Verification
+  verified BOOLEAN DEFAULT false,
+  verified_at TIMESTAMP,
+  verification_error TEXT,
+
+  tenant_id TEXT NOT NULL,
+  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+
+  FOREIGN KEY (message_id) REFERENCES whatsapp_messages(message_id),
+  FOREIGN KEY (tenant_id) REFERENCES tenants(id),
+  INDEX idx_message_sig (message_id),
+  INDEX idx_verified (verified)
+);
+```
+
+---
+
+## 4. Integration Points with Other Agents
+
+### 4.1 S2-H03: Maintenance Log Integration
+
+**WhatsApp → Maintenance:**
+
+```
+User: "@NaviDocs log maintenance engine service cost:450 provider:Marina"
+
+↓
+
+POST /api/v1/tenants/{tenantId}/maintenance/create
+{
+  "boat_id": "boat-123",
+  "service_type": "engine",
+  "date": "2025-11-13",
+  "cost": 450,
+  "cost_currency": "EUR",
+  "provider": "Marina Service SRL",
+  "estimated_next_due": "2026-05-13",
+  "created_via": "whatsapp",
+  "whatsapp_message_id": "msg-123",
+  "source_agent": "S2-H08"
+}
+
+↓
+
+Response:
+✅ Logged engine service
+Cost: €450 | Provider: Marina Service SRL
+Next due: 2025-05-13 (6 months)
+Maintenance entry: if://maintenance/navidocs/boat-123/service-001
+```
+
+**Maintenance → WhatsApp (Reminder Alert):**
+
+```
+S2-H03 scheduled reminder: 14 days before next maintenance due
+
+↓
+
+POST /api/v1/tenants/{tenantId}/whatsapp/send-message
+{
+  "boat_id": "boat-123",
+  "group_id": "group-riviera-50-001",
+  "message_type": "maintenance-reminder",
+  "title": "Engine Service Due",
+  "content": "Engine service due in 14 days (2025-12-15)",
+  "trigger_event": "maintenance-due:service-001",
+  "trigger_source_agent": "S2-H03"
+}
+
+↓
+
+Group message:
+🔔 Maintenance Alert
+Service: Engine
+Due: 2025-12-15 (14 days)
+Provider: Marina Service SRL
+Captain: Please schedule → [reschedule link]
+```
+
+### 4.2 S2-H06: Expense Tracking Integration
+
+**WhatsApp → Expenses:**
+
+```
+User: "📸 [fuel receipt photo] @NaviDocs log this expense fuel"
+
+↓
+
+1. Extract attachment, run OCR
+2. Parse text: amount, vendor, category
+3. POST /api/v1/tenants/{tenantId}/expenses/create
+{
+  "boat_id": "boat-123",
+  "amount": 120,
+  "currency": "EUR",
+  "category": "fuel",
+  "vendor": "Marina Port Authority",
+  "date": "2025-11-13",
+  "receipt_image_url": "s3://navidocs/receipts/boat-123/receipt-001.jpg",
+  "receipt_ocr_text": "...",
+  "requester_phone": "34658888888",
+  "requester_name": "Captain José",
+  "created_via": "whatsapp",
+  "whatsapp_message_id": "msg-123",
+  "status": "pending-approval",
+  "source_agent": "S2-H08"
+}
+
+↓
+
+Group message:
+✅ Logged fuel expense
+Amount: €120
+Vendor: Marina Port Authority
+Status: Pending owner approval
+[Approve] [Reject]
+```
+
+**Expense Reimbursement Workflow:**
+
+```
+User: Captain taps [Approve]
+
+↓
+
+POST /api/v1/tenants/{tenantId}/expenses/approve
+{ "expense_id": "exp-123", "approved_by": "owner", "approved_at": "2025-11-13T10:05:00Z" }
+
+↓
+
+Group message:
+✅ Expense Approved
+Captain José gets reimbursed €120
+Marked as: Reimbursement Pending
+Next payment: 2025-11-30 (monthly)
+```
+
+### 4.3 S2-H02: Inventory Integration
+
+**WhatsApp → Inventory:**
+
+```
+User: "@NaviDocs add inventory Tender Zodiac purchase:35000 warranty:2027-06-15"
+
+↓
+
+POST /api/v1/tenants/{tenantId}/inventory/create
+{
+  "boat_id": "boat-123",
+  "item_name": "Tender Zodiac",
+  "category": "tender",
+  "zone": "stern storage",
+  "purchase_date": "2025-06-15",
+  "purchase_price": 35000,
+  "purchase_currency": "EUR",
+  "warranty_expiration": "2027-06-15",
+  "created_via": "whatsapp",
+  "whatsapp_message_id": "msg-123",
+  "source_agent": "S2-H08"
+}
+
+↓
+
+Group message:
+✅ Added to inventory
+Item: Tender Zodiac
+Purchase Price: €35,000
+Warranty: 2027-06-15
+Value Tracking: ✅
+Search: if://inventory/navidocs/boat-123/tender-zodiac
+```
+
+### 4.4 S2-H09: Document Versioning Integration
+
+**Document Uploaded → WhatsApp Notification:**
+
+```
+User uploads new Tender Warranty document in NaviDocs app
+
+↓
+
+S2-H09 triggers webhook: POST /api/v1/tenants/{tenantId}/whatsapp/document-notification
+{
+  "boat_id": "boat-123",
+  "document_type": "warranty",
+  "document_name": "Tender Warranty v2",
+  "replaced_document": "Tender Warranty v1",
+  "uploaded_by": "Francesca Moretti",
+  "uploaded_at": "2025-11-13T10:15:00Z",
+  "doc_version": "v2",
+  "doc_citation_id": "if://doc/navidocs/boat-123/tender-warranty-v2",
+  "source_agent": "S2-H09"
+}
+
+↓
+
+Group message:
+📄 New Document Uploaded
+Tender Warranty v2 (8 pages)
+Replaces: Tender Warranty v1
+Uploaded by: Francesca Moretti (Riviera After-Sales)
+Document: if://doc/navidocs/boat-123/tender-warranty-v2
+[View in App]
+```
+
+**WhatsApp Search → Document:**
+
+```
+User: "@NaviDocs where's the tender warranty?"
+
+↓
+
+S2-H08 AI Agent calls S2-H09 API:
+POST /api/v1/tenants/{tenantId}/documents/search
+{ "boat_id": "boat-123", "query": "tender warranty" }
+
+↓
+
+S2-H09 Response:
+{
+  "documents": [
+    {
+      "id": "doc-456",
+      "name": "Tender Warranty v2",
+      "type": "warranty",
+      "version": "v2",
+      "created_date": "2025-06-15",
+      "expires_date": "2027-06-15",
+      "citation_id": "if://doc/navidocs/boat-123/tender-warranty-v2",
+      "url": "https://app.navidocs.com/boats/boat-123/documents/doc-456"
+    }
+  ]
+}
+
+↓
+
+Group message:
+✅ Found: Tender Warranty v2
+Expires: 2027-06-15 (20 months)
+Document: if://doc/navidocs/boat-123/tender-warranty-v2
+[View Warranty]
+```
+
+---
+
+## 5. IF.TTT Compliance (Traced, Timestamped, Tamper-evident)
+
+### 5.1 Signature Mechanism
+
+**Ed25519 Signature Process:**
+
+```javascript
+// At tenant setup, generate Ed25519 keypair
+const keyPair = nacl.sign.keyPair();
+tenant.ed25519_private_key = base64(keyPair.secretKey);
+tenant.ed25519_public_key = base64(keyPair.publicKey);
+
+// When signing a message
+function signMessage(message, tenantPrivateKey) {
+  const messageBytes = new TextEncoder().encode(message);
+  const secretKey = nacl.util.decodeBase64(tenantPrivateKey);
+
+  const signature = nacl.sign.detached(messageBytes, secretKey);
+  const signatureBase64 = nacl.util.encodeBase64(signature);
+
+  return {
+    ed25519_signature: signatureBase64,
+    sha256_hash: crypto.createHash('sha256').update(message).digest('hex')
+  };
+}
+
+// When verifying a message
+function verifyMessage(message, signature, tenantPublicKey) {
+  const messageBytes = new TextEncoder().encode(message);
+  const signatureBytes = nacl.util.decodeBase64(signature);
+  const publicKeyBytes = nacl.util.decodeBase64(tenantPublicKey);
+
+  try {
+    nacl.sign.detached.verify(messageBytes, signatureBytes, publicKeyBytes);
+    return true;
+  } catch {
+    return false;
+  }
+}
+```
+
+### 5.2 Citation ID Format
+
+**Standard Citation ID Structure:**
+
+```
+if://chat/navidocs/boat-{boatId}/msg-{messageId}
+if://chat/navidocs/boat-123/msg-wamid.ABC123=
+
+Components:
+- Scheme: "if://" (InfraFabric protocol)
+- Domain: "chat" (message domain)
+- Service: "navidocs"
+- Resource: "boat-{id}/msg-{id}"
+
+Examples:
+- if://chat/navidocs/boat-123/msg-wamid.ABC123=
+- if://chat/navidocs/boat-123/response-resp-001
+- if://chat/navidocs/boat-123/attachment-attach-001
+```
+
+### 5.3 Audit Trail Entry
+
+**Complete Audit Record:**
+
+```sql
+INSERT INTO whatsapp_messages (
+  message_id,
+  boat_id,
+  group_id,
+  sender_name,
+  sender_phone,
+  content,
+  timestamp,
+  ed25519_signature,
+  sha256_hash,
+  citation_id,
+  tenant_id
+) VALUES (
+  'wamid.ABC123=',
+  'boat-123',
+  'group-riviera-50-001',
+  'Captain José',
+  '+34658888888',
+  '@NaviDocs where''s the tender warranty?',
+  '2025-11-13T10:00:00Z',
+  'Hy3r5hR8kL9m0n1o2p3q4r5s6t7u8v9w0x1y2z3=',  -- Ed25519 sig
+  'abc123def456...',                             -- SHA-256 hash
+  'if://chat/navidocs/boat-123/msg-wamid.ABC123=',
+  'tenant-riviera'
+);
+
+-- Corresponding audit trail
+INSERT INTO if_ttt_audit_trail (
+  audit_id,
+  message_id,
+  action,
+  actor_id,
+  actor_type,
+  original_content,
+  ed25519_signature,
+  sha256_hash,
+  action_timestamp,
+  tenant_id
+) VALUES (
+  'audit-001',
+  'wamid.ABC123=',
+  'created',
+  '34658888888',  -- Captain José's phone
+  'user',
+  '@NaviDocs where''s the tender warranty?',
+  'Hy3r5hR8kL9m0n1o2p3q4r5s6t7u8v9w0x1y2z3=',
+  'abc123def456...',
+  '2025-11-13T10:00:00Z',
+  'tenant-riviera'
+);
+```
+
+### 5.4 Tamper Detection
+
+**SHA-256 Verification:**
+
+```javascript
+// Detect if message has been modified
+function detectTamper(storedMessage, storedHash) {
+  const currentHash = crypto.createHash('sha256').update(storedMessage.content).digest('hex');
+
+  if (currentHash !== storedHash) {
+    // Message has been modified!
+    return {
+      tampered: true,
+      stored_hash: storedHash,
+      current_hash: currentHash,
+      status: 'CRITICAL - Message integrity compromised'
+    };
+  }
+
+  return {
+    tampered: false,
+    status: 'Message integrity verified'
+  };
+}
+
+// Signature verification
+function verifyMessageIntegrity(message, signature, publicKey) {
+  return {
+    signature_valid: verifyEd25519(message, signature, publicKey),
+    hash_matches: detectTamper(message, message.sha256_hash),
+    overall_status: 'authentic'  // Both must pass
+  };
+}
+```
+
+---
+
+## 6. Multi-Tenant Security Architecture
+
+### 6.1 Boat Isolation
+
+**Tenant → Boat → Chat Isolation:**
+
+```javascript
+// Webhook handler enforces tenant boundaries
+POST /api/v1/tenants/{tenantId}/whatsapp/webhooks/messages
+
+// 1. Verify tenant authorization
+const tenant = await db.query('SELECT * FROM tenants WHERE id = ?', [tenantId]);
+if (!tenant) return 403 Forbidden;
+
+// 2. Extract boatId from message metadata
+const phoneNumberId = messageData.metadata.phone_number_id;
+const boatAssignment = await db.query(
+  'SELECT boat_id FROM whatsapp_groups WHERE phone_number_id = ? AND tenant_id = ?',
+  [phoneNumberId, tenantId]
+);
+if (!boatAssignment) return 403 Forbidden;
+
+// 3. Verify sender is in group
+const senderPhone = messageData.messages[0].from;
+const groupMember = await db.query(
+  `SELECT * FROM whatsapp_group_members
+   WHERE group_id = ? AND member_phone = ? AND is_active = true`,
+  [boatAssignment.group_id, senderPhone]
+);
+if (!groupMember) return 403 Forbidden;
+
+// 4. All subsequent queries scoped to this boat & tenant
+// - Messages queries: WHERE boat_id = ? AND tenant_id = ?
+// - Maintenance queries: WHERE boat_id = ? AND tenant_id = ?
+// - Expense queries: WHERE boat_id = ? AND tenant_id = ?
+// - Inventory queries: WHERE boat_id = ? AND tenant_id = ?
+```
+
+### 6.2 Authentication & API Key Rotation
+
+**Tenant API Keys:**
+
+```sql
+CREATE TABLE tenant_api_keys (
+  key_id TEXT PRIMARY KEY,
+  tenant_id TEXT NOT NULL,
+
+  api_key_hash TEXT NOT NULL,        -- SHA-256 hash of actual key
+  key_name TEXT,                      -- "whatsapp-webhook", "s2h03-integration"
+
+  -- Rotation policy
+  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+  expires_at TIMESTAMP,               -- 90-day rotation
+  last_used_at TIMESTAMP,
+
+  -- Permissions
+  scopes TEXT,                        -- JSON array: ["whatsapp:receive", "maintenance:read", "expense:write"]
+  rate_limit_per_minute INTEGER DEFAULT 60,
+
+  status TEXT CHECK(status IN ('active', 'rotated', 'revoked')),
+
+  FOREIGN KEY (tenant_id) REFERENCES tenants(id),
+  INDEX idx_tenant_keys (tenant_id)
+);
+
+-- Webhook verification header
+X-Hub-Signature-256: sha256=<HASH>
+-- Where HASH = HMAC-SHA256(webhook_payload, tenant_app_secret)
+```
+
+### 6.3 Role-Based Access Control (RBAC)
+
+**WhatsApp Group Member Roles:**
+
+```
+Owner:
+- Can approve/reject expenses
+- Can view all chats
+- Can reschedule maintenance
+- Can upload documents
+- Can manage group membership
+
+Captain:
+- Can log maintenance (read-only)
+- Can log expenses (with owner approval)
+- Can see maintenance reminders
+- Can see document updates
+- Cannot approve own expenses
+- Cannot remove other members
+
+After-Sales Manager:
+- Can upload documents
+- Can post announcements
+- Can view all chats
+- Cannot approve expenses
+- Cannot log maintenance
+- Cannot manage members
+
+NaviDocs AI Agent (System):
+- Can post reminders (scheduled jobs)
+- Can respond to questions
+- Can execute commands (if sender has permission)
+- Can log system messages
+- Cannot post arbitrary messages
+```
+
+**Command Permission Matrix:**
+
+```
+Command                  Owner  Captain  After-Sales  AI-Agent
+@NaviDocs log expense      ✓      ✓         ✗          ✓
+@NaviDocs approve expense  ✓      ✗         ✗          ✗
+@NaviDocs log maintenance  ✓      ✓         ✗          ✓
+@NaviDocs add inventory    ✓      ✗         ✗          ✓
+@NaviDocs upload document  ✓      ✓         ✓          ✗
+@NaviDocs search documents ✓      ✓         ✓          ✓
+@NaviDocs list inventory   ✓      ✓         ✓          ✓
+```
+
+---
+
+## 7. API Specification
+
+### 7.1 Webhook Receiver Endpoint
+
+```
+POST /api/v1/tenants/{tenantId}/whatsapp/webhooks/messages
+
+Request Headers:
+- Content-Type: application/json
+- X-Hub-Signature-256: sha256=<HMAC-SHA256>
+- Authorization: Bearer {WEBHOOK_VERIFY_TOKEN}
+
+Request Body: WhatsApp Cloud API webhook payload
+
+Response: 200 OK
+{
+  "status": "received",
+  "message_id": "wamid.ABC123=",
+  "boat_id": "boat-123",
+  "processing_status": "queued"
+}
+
+Error Responses:
+- 400: Invalid payload format
+- 403: Tenant not authorized, signature invalid
+- 409: Message already processed (idempotency check)
+```
+
+### 7.2 Message Send Endpoint
+
+```
+POST /api/v1/tenants/{tenantId}/whatsapp/send-message
+
+Request Body:
+{
+  "boat_id": "boat-123",
+  "recipient_phone": "+34619999999",
+  "recipient_group_id": "group-riviera-50-001",
+  "message_type": "text|command-response|alert|reminder",
+  "content": {
+    "body": "Your message here"
+  },
+  "metadata": {
+    "source_agent": "S2-H08",
+    "related_message_id": "wamid.ABC123=",
+    "action": "answer-question"
+  }
+}
+
+Response: 200 OK
+{
+  "status": "sent",
+  "message_id": "wamid.NEW123=",
+  "timestamp": "2025-11-13T10:05:00Z",
+  "boat_id": "boat-123"
+}
+```
+
+### 7.3 Message History Endpoint
+
+```
+GET /api/v1/tenants/{tenantId}/boats/{boatId}/whatsapp/messages
+
+Query Parameters:
+- group_id: "group-riviera-50-001" (optional, default: all groups for boat)
+- from_date: "2025-11-01" (optional)
+- to_date: "2025-11-13" (optional)
+- sender: "captain@..." (optional)
+- page: 1 (default)
+- limit: 50 (default, max 100)
+- sort: "timestamp desc" (default)
+
+Response: 200 OK
+{
+  "messages": [
+    {
+      "message_id": "wamid.ABC123=",
+      "sender_name": "Captain José",
+      "sender_role": "captain",
+      "content": "@NaviDocs where's the tender warranty?",
+      "timestamp": "2025-11-13T10:00:00Z",
+      "message_type": "text",
+      "status": "processed",
+      "citation_id": "if://chat/navidocs/boat-123/msg-wamid.ABC123="
+    },
+    {
+      "message_id": "resp-001",
+      "sender_name": "NaviDocs Bot",
+      "sender_role": "ai-agent",
+      "content": "Tender warranty expires 2025-06-15...",
+      "timestamp": "2025-11-13T10:00:15Z",
+      "message_type": "text",
+      "status": "processed",
+      "citation_id": "if://chat/navidocs/boat-123/response-resp-001",
+      "in_reply_to": "wamid.ABC123="
+    }
+  ],
+  "pagination": {
+    "page": 1,
+    "total_messages": 127,
+    "pages": 3
+  }
+}
+```
+
+### 7.4 Command Execution Endpoint
+
+```
+POST /api/v1/tenants/{tenantId}/whatsapp/execute-command
+
+Request Body:
+{
+  "boat_id": "boat-123",
+  "sender_phone": "+34658888888",
+  "sender_name": "Captain José",
+  "sender_role": "captain",
+  "command_text": "@NaviDocs log maintenance engine service cost:450",
+  "source_message_id": "wamid.ABC123=",
+  "timestamp": "2025-11-13T10:00:00Z"
+}
+
+Response: 200 OK
+{
+  "status": "executed",
+  "command_action": "log-maintenance",
+  "result": {
+    "success": true,
+    "maintenance_id": "maint-001",
+    "response_message": "✅ Logged engine service cost: €450"
+  },
+  "timestamp": "2025-11-13T10:00:01Z"
+}
+```
+
+---
+
+## 8. Example Conversations
+
+### Example 1: Owner Queries Maintenance
+
+```
+Owner (Pasquale): When was the last engine service?
+
+NaviDocs Bot: ✅ Last engine service: 2025-10-15 (29 days ago)
+Cost: €450
+Provider: Marina Service SRL
+Next due: 2026-04-15 (scheduled in 153 days)
+Document: if://maintenance/navidocs/boat-123/service-engine-2025-10-15
+
+[Log Another Service] [Schedule Next]
+
+---
+
+Owner: Schedule engine service for December 15
+
+NaviDocs Bot: ✅ Engine service scheduled for 2025-12-15
+Captain José will receive notification
+Estimated cost: €450 (based on last service)
+Status: Captain to confirm with Marina Service SRL
+
+Captain: Marina confirmed! Service scheduled 2025-12-15 at 10:00 AM
+
+NaviDocs Bot: ✅ Confirmation recorded
+Service: Engine maintenance
+Date: 2025-12-15 10:00 AM
+Location: Marina Service SRL, Porto Vecchio
+Document: if://maintenance/navidocs/boat-123/service-engine-2025-12-15
+```
+
+### Example 2: Captain Logs Expense
+
+```
+Captain (José): 📸 [fuel receipt image] @NaviDocs log this fuel
+
+[NaviDocs processes receipt OCR]
+
+NaviDocs Bot: 📋 Receipt Recognized:
+Vendor: Porto Vecchio Marina
+Amount: €115.50
+Date: 2025-11-13
+Category: Fuel & Provisioning
+Status: Pending owner approval
+
+[Confirm] [Edit] [Cancel]
+
+---
+
+Captain: Confirm
+
+NaviDocs Bot: ✅ Logged fuel expense
+Amount: €115.50
+Receipt: if://receipt/navidocs/boat-123/receipt-001
+Status: Pending Owner Approval
+
+Owner approves after 2 hours:
+
+NaviDocs Bot: ✅ Expense Approved
+Captain José receives €115.50 reimbursement
+Payment scheduled: 2025-11-30
+Receipt archived: if://receipt/navidocs/boat-123/receipt-001
+
+---
+
+November 30 (Auto-generated):
+
+NaviDocs Bot: 💳 Monthly Reimbursement Summary
+Captain José:
+  - Fuel (€115.50)
+  - Provisions (€87.23)
+  - Minor repairs (€45.00)
+  Total: €247.73
+
+Payment status: Marked as paid
+Payment method: Bank transfer to [Captain account]
+Document: if://expense/navidocs/boat-123/reimbursement-nov-2025
+```
+
+### Example 3: After-Sales Posts Document
+
+```
+After-Sales (Francesca): @NaviDocs upload warranty documents
+
+NaviDocs Bot: 📄 Ready to accept documents
+Expected: Tender warranty, Electronics warranty, Engine warranty
+
+Francesca: 📸 [uploads 3 PDF images]
+
+NaviDocs Bot: Processing documents...
+[Wait 2 seconds]
+
+NaviDocs Bot: ✅ 3 documents processed
+1. Tender Warranty
+   - Uploaded: 2025-11-13
+   - Expires: 2027-06-15
+   - Document: if://doc/navidocs/boat-123/tender-warranty-v1
+
+2. Electronics Warranty
+   - Uploaded: 2025-11-13
+   - Expires: 2026-11-13
+   - Document: if://doc/navidocs/boat-123/electronics-warranty-v1
+
+3. Engine Warranty
+   - Uploaded: 2025-11-13
+   - Expires: 2026-11-13
+   - Document: if://doc/navidocs/boat-123/engine-warranty-v1
+
+---
+
+All stakeholders notified:
+
+Owner: 📄 New Warranty Documents Uploaded
+2 documents uploaded by Riviera After-Sales
+Action: Check warranty expiration dates in Calendar
+
+Captain: 📄 New Warranty Documents Uploaded
+3 documents available for reference
+Use: "@NaviDocs where's the tender warranty?" to find docs
+
+Francesca: ✅ Upload Complete
+3 documents archived in NaviDocs
+Boat team notified
+```
+
+### Example 4: Inventory Management
+
+```
+After-Sales (Francesca): @NaviDocs add inventory Garmin GPSMAP 8600 category:electronics
+purchase:3500 warranty:2026-11-13
+
+NaviDocs Bot: ✅ Added to inventory
+Item: Garmin GPSMAP 8600
+Category: Electronics
+Zone: [Auto-detect: Helm]
+Purchase Price: €3,500
+Warranty: 2026-11-13 (365 days)
+Current Value Est.: €2,800 (80% retention)
+
+Document: if://inventory/navidocs/boat-123/garmin-gpsmap-8600
+
+---
+
+Owner: @NaviDocs list inventory category:electronics
+
+NaviDocs Bot: 📱 Electronics Inventory
+Total items: 6
+Total value: €28,500
+
+1. Garmin GPSMAP 8600 - €3,500 (Warranty: 2026-11-13)
+2. Autopilot System - €8,200 (Warranty: 2025-08-20 - EXPIRED)
+3. VHF Radio - €2,100 (Warranty: 2026-03-15)
+4. Depth Sounder - €1,800 (Warranty: 2025-12-10 - 27 days left)
+5. Sea Breeze Air Conditioning - €12,900 (Warranty: 2027-06-15)
+
+[Sort by: Warranty | Value | Category]
+[Export Inventory]
+```
+
+---
+
+## 9. IF.TTT Compliance Checklist
+
+Use this checklist to verify all messages meet Traced, Timestamped, Tamper-evident standards:
+
+### Checklist Items
+
+- [ ] **Message Traceability:**
+  - [ ] Every message has unique `message_id`
+  - [ ] Every message has `sender_name` and `sender_phone`
+  - [ ] Sender role is recorded (`owner`, `captain`, `after-sales`, `ai-agent`)
+  - [ ] Citation ID is generated (if://chat/navidocs/boat-{boatId}/msg-{messageId})
+  - [ ] Message stored in `whatsapp_messages` table
+
+- [ ] **Timestamp Verification:**
+  - [ ] `timestamp` field set to exact WhatsApp timestamp
+  - [ ] `received_at` set to server receipt time
+  - [ ] `processed_at` set when AI response sent
+  - [ ] All times in ISO 8601 format (UTC)
+  - [ ] Time synchronization checked (NTP)
+
+- [ ] **Signature & Hash:**
+  - [ ] Ed25519 signature generated using tenant private key
+  - [ ] Signature covers exact message content (no modifications)
+  - [ ] SHA-256 hash calculated for message content
+  - [ ] Signature stored in `ed25519_signature` field
+  - [ ] Hash stored in `sha256_hash` field
+
+- [ ] **Tamper Detection:**
+  - [ ] Signature verification passes on all stored messages
+  - [ ] Hash verification passes on all stored messages
+  - [ ] Audit trail entry created for all changes
+  - [ ] Update operations create new audit records (don't overwrite)
+
+- [ ] **AI Responses:**
+  - [ ] Response has unique `response_id`
+  - [ ] Response has `citation_id` (if://chat/.../response-{id})
+  - [ ] Response signed with same tenant key as original message
+  - [ ] Response hash matches stored content
+  - [ ] AI model ID recorded (`claude-3-5-haiku-20241022`)
+
+- [ ] **Command Execution:**
+  - [ ] Command parser validates @NaviDocs syntax
+  - [ ] Command forwarded to target agent (S2-H03, S2-H06, etc.)
+  - [ ] Target agent response recorded with its own signature
+  - [ ] Command execution logged in `whatsapp_ai_responses`
+  - [ ] Command result stored with timestamp
+
+- [ ] **Audit Trail:**
+  - [ ] Entry created for message creation
+  - [ ] Entry created for each update/modification
+  - [ ] Entry created for command execution
+  - [ ] Entry created for approval/rejection
+  - [ ] Each audit entry signed and hashed
+
+- [ ] **Multi-Tenant Isolation:**
+  - [ ] All queries filtered by `tenant_id` AND `boat_id`
+  - [ ] Tenant cannot access other tenant's messages
+  - [ ] Boat cannot access other boat's chats within same tenant
+  - [ ] API authorization verified before processing
+
+- [ ] **Attachment Handling:**
+  - [ ] Receipt photos stored with SHA-256 hash
+  - [ ] Attachment `media_id` recorded from WhatsApp
+  - [ ] OCR text stored separately (for searchability)
+  - [ ] Original image preserved (for legal/tax purposes)
+
+- [ ] **System Messages:**
+  - [ ] Reminders, alerts, notifications tracked as system messages
+  - [ ] System messages marked with `message_type`: `system`
+  - [ ] System messages signed (not user-generated)
+  - [ ] Trigger event recorded (e.g., `maintenance-due:service-001`)
+
+- [ ] **Compliance Testing:**
+  - [ ] Run `verify_message_signatures.sql` monthly
+  - [ ] Run `detect_tampered_messages.sql` monthly
+  - [ ] Check `if_ttt_audit_trail` for completeness
+  - [ ] Verify no messages modified after creation
+
+---
+
+## 10. Deployment Checklist
+
+### Pre-Deployment
+
+- [ ] WhatsApp Business Account created (contact Meta)
+- [ ] WhatsApp Business API app configured
+- [ ] Webhook URL registered with Meta
+- [ ] Webhook verify token generated (random 32+ character string)
+- [ ] Ed25519 keypair generated for tenant signing
+- [ ] SSL certificate deployed on webhook endpoint
+- [ ] Rate limiting configured (60 req/min per tenant)
+- [ ] Database migrations run (all tables above created)
+- [ ] Meilisearch configured with whatsapp_search_index
+- [ ] Redis/BullMQ job queues configured
+- [ ] Claude API key configured (read from env)
+- [ ] S3 bucket created for receipt/attachment storage
+
+### Post-Deployment
+
+- [ ] Test webhook with Meta's test notification
+- [ ] Send test message: "@NaviDocs test"
+- [ ] Verify message logged in database
+- [ ] Verify signature and hash correct
+- [ ] Test command: "@NaviDocs help"
+- [ ] Test integration with S2-H03 (log maintenance)
+- [ ] Test integration with S2-H06 (log expense)
+- [ ] Test integration with S2-H02 (add inventory)
+- [ ] Test integration with S2-H09 (search documents)
+- [ ] Verify IF.TTT audit trail created
+- [ ] Test multi-tenant isolation (attempt cross-tenant access)
+- [ ] Monitor for webhook delivery failures
+- [ ] Monitor API response times
+- [ ] Configure alerts for errors/failures
+
+---
+
+## 11. Glossary & References
+
+**IF.TTT (Traced, Timestamped, Tamper-evident):**
+- Traced: Every message has attribution (who, what, when)
+- Timestamped: Precise UTC timestamps on all events
+- Tamper-evident: Cryptographic signatures detect modifications
+
+**Citation ID:**
+- Globally unique identifier for each message/response
+- Format: `if://chat/navidocs/boat-{id}/msg-{id}`
+- Used for cross-referencing in audit trails
+
+**Ed25519:**
+- Modern public-key signature algorithm
+- Used to sign all messages (tenant private key)
+- Verified using tenant public key
+
+**SHA-256:**
+- Cryptographic hash function
+- Detects any modification to message content
+- Stored for tamper detection verification
+
+**S2-H03, S2-H06, S2-H02, S2-H09:**
+- Agent IDs for related NaviDocs systems
+- S2-H03: Maintenance Log Management
+- S2-H06: Expense Tracking & Accounting
+- S2-H02: Inventory Management
+- S2-H09: Document Versioning
+
+**WhatsApp Business API:**
+- Cloud API for programmatic message sending/receiving
+- Webhook-based event delivery
+- Rate limiting: 60 messages/sec per phone number
+
+**Claude API:**
+- Anthropic's AI language model API
+- Model: claude-3-5-haiku-20241022 (lightweight, fast)
+- Used for natural language understanding & response generation
+
+---
+
+## Document Status
+
+**Created:** 2025-11-13 by S2-H08
+**Citation ID:** if://doc/navidocs/session-2/whatsapp-integration-spec
+**Version:** 1.0
+**Status:** FINAL SPECIFICATION
+**Next Review:** Post-MVP deployment feedback integration