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Product & architecture design · LLM / RAG

AI Guest Assistant — LLM/RAG SaaS Design

A complete pre-build design for an AI WhatsApp assistant for short-term-rental hosts: full RAG architecture, a per-property unit-economics model, a pilot program with success metrics defined up front, and a 3-person operating model. Every deliverable is generated from code (Python + ReportLab) — versioned, diffable, re-rendered per revision — and presented honestly as design work, not a shipped product.

LLM / RAG architecture Whisper + GPT Qdrant + Postgres WhatsApp Business API FastAPI / Next.js Python + ReportLab
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Built with agentic AI. Development on this project runs through multi-agent Claude Code workflows — developer → independent-reviewer cycles with evidence gates, batched into unattended runs that execute overnight and resume from committed ledgers. How the agent system works →

The product mechanism

A host uploads walkthrough videos and PDFs once; guests then get instant, grounded answers on WhatsApp — including auto-cut video clips of the exact moment that answers their question.

Ingestion pipeline

  • Walkthrough videos and house-manual PDFs land in object storage; FFmpeg extracts audio, Whisper transcribes, an LLM pass detects topics (WiFi, check-in, parking…).
  • Transcript chunks are embedded into Qdrant; structured property/booking data lives in Postgres.
  • Conversations map to booking, property and host, so every answer is scoped to the right apartment.

Guest conversation loop

  • Messages arrive via the WhatsApp Business API; RAG retrieval runs over the property's own knowledge — answers are grounded in the host's actual walkthrough.
  • When the best evidence is a video moment, FFmpeg auto-cuts a clip at the right timestamp and sends it with the reply.
  • Low-confidence answers escalate to the host — the assistant's job is to handle the routine 80%, measurably.

Designed like engineering

Unit economics before product code

The core design artifact is a dataclass-driven cost model that separates one-time onboarding from monthly run-rate — and the real cost driver, narrated media (Whisper path) from silent media — fanned across portfolio sizes from 10 to 200 listings. Pricing conversations with property managers happen over a spreadsheet-grade model, not a guess.

Pilot, demo & operating model

  • Pilot tiers with success metrics defined before the pilot starts: % handled without a human, escalation rate, time-to-first-reply.
  • A repeatable 15-minute demo with a fixed demo-apartment fixture, so on-stage answers are deterministic; every sales-call promise becomes a tracked issue.
  • A 3-person operating model (2 dev, 1 sales) and a full deployment story: Next.js + Clerk on Vercel, FastAPI workers, Stripe billing, staging-before-prod.