SECTION 1 — EXECUTIVE SYSTEM ARCHITECTURE OVERVIEW - System Flow: Stripe Payment / Google Drive Receipt -> Webhook -> OpenAI OCR & Parsing -> QuickBooks API -> HubSpot CRM Log - Tech Stack Table: * Trigger: Google Drive (New Receipt Uploaded) -> Protocol: Webhook * Action 1: OpenAI API (Extract Vendor, Date, Amount, Line Items) -> Protocol: REST API * Action 2: QuickBooks Online (Create Expense / Bill Entry) -> Protocol: OAuth 2.0 API * Action 3: HubSpot (Update Client Account Financial Record) -> Protocol: REST API - Security Summary: TLS 1.3 encryption in transit, OAuth 2.0 authentication token rotation, and zero data retention on LLM endpoints. SECTION 2 — STEP-BY-STEP AUTOMATION WORKFLOW BLUEPRINT - Phase 1: Ingestion — Webhook captures new receipt PDF in Google Drive; triggers PDF text extraction module via Make.com. - Phase 2: Processing — Claude/OpenAI parses unformatted text into structured JSON payload (vendor, tax ID, line items, total). - Phase 3: Sync — System validates totals; creates ledger entry in QuickBooks Online and logs activity in HubSpot. SECTION 3 — EXCEPTION HANDLING & HUMAN-IN-THE-LOOP (HITL) PROTOCOL - Error Handling: Automatic 3-step retry with exponential backoff if QuickBooks API is rate-limited. - HITL Trigger: Receipts exceeding $5,000 or with confidence scores below 85% are flagged for human review in Slack. - Fallback: Unresolved items move to a "Requires Manual Review" Airtable queue. SECTION 4 — CLIENT ONBOARDING & SCALING ROADMAP - Week 1: Webhook configuration, OAuth authentication setup, and sandbox testing. - Week 2: Edge-case auditing (e.g., foreign currencies, corrupted PDFs) and HITL Slack trigger validation. - Week 3: Production go-live, ledger monitoring, and admin training.