People and teams who receive commitments, dates and documents over WhatsApp and need dependable memory with human confirmation.
CASE 10 · TECHNICAL PILOT MULTIMODAL ASSISTANT · DETERMINISTIC CORE
Lía
The LLM interprets; the application decides.
Lía is a WhatsApp-first personal assistant that turns voice notes, documents and photos into structured memory with provenance: decisions, questions and commitments. A deterministic engine governs states, permissions and billing, while two models —an interpreter and an evaluator— work under explicit authority limits.
CASE VIDEO
PROJECT CARD / RECRUITER VIEW
The project's technical dossier.
I designed and built the whole system: the deterministic engine, the resumable multimodal pipeline (Whisper + OCR with evidence regions), the JEV evaluation layer, multi-tenant RLS, the magic-link portal and the sandbox billing loop.
Backend, APIs, deployment, testing and controls.
- DEPLOYMENT
- Staging on Oracle Cloud: api, worker, web, media, nginx and postgres; health gates, offsite backups and rollback drills.
- BACKEND / APIS
- Meta WhatsApp Cloud API with signed (HMAC) webhooks, magic-link portal and optional channels (Telegram, Google).
- AI LAYER
- DeepSeek interprets; JEV audits with closed options and confidence, with per-flow off/shadow/enforce modes and its own budget ledger.
- DATA / SECURITY
- Account- and workspace-level isolation with RLS, five roles with explicit scopes, and identity linking via a one-time challenge (HMAC fingerprint only).
- BILLING
- Versioned COP/USD pricebook, immutable quotes, idempotent webhooks verified with HMAC over the raw bytes, replay deduplication, a 14-day cardless trial and reconciled entitlements.
- TESTING
- 134/134 user journeys, a 7/7 adversarial go-live review with zero critical or high findings, and 434/434 local tests in the JEV integration.
- 01WhatsApp Cloud API + signed webhooks
- 02Worker: resumable audio + Whisper + OCR with evidence
- 03Memory with provenance · retrieval isolated by account/workspace/owner
- 04Multi-tenant PostgreSQL with RLS · five roles
- 05Magic-link portal + sandbox billing
- Staging on Oracle Cloud: 6 healthy containers and readyz 200
- 134/134 user journeys validated
- JEV: 39/39 real evaluations (p50 448 ms)
- Complete billing loop in sandbox, deliberately switched off
- The model never governs state, permissions or money
- A hard boundary in code and tests between interpretation and decision
- A resumable, idempotent pipeline: nothing lost, nothing double-charged
- Keep commercial billing off until external approvals exist
- VIDEO
- 3:33 narrated walkthrough (English)
- DEMO
- Private staging pilot
- SCREENSHOTS
- Shared with coordinated access
- The pilot lives in staging: commercial billing stays off until external approvals exist —an explicit decision, not a forgotten to-do.
- JEV is a probabilistic evaluator: it audits, orders and lowers confidence; authority remains in code.
- No credentials or tenant data are published; the demo is shared with coordinated access.
Watch the case video
OPEN / REQUEST01 / PROBLEM
Conversation is where information goes to die.
Commitments, dates and decisions sit buried inside voice notes and documents. The obvious fix —letting an LLM handle it— is dangerous: models hallucinate and should never touch your money or your permissions.
02 / DESIGN DECISION
A deterministic core with LLMs at the edge.
The LLM interprets and extracts; the application governs states, permissions and billing. JEV audits every interpretation with closed options and confidence, under hard authority limits.
SYSTEM / END TO END
The product as an explicit flow.
Each phase has a distinct responsibility. That separation makes it possible to observe, test and fix the system without relying on intuition.
- 01CAPTURE
Capture
Voice, documents and photos come in over WhatsApp with signed webhooks.
- 02AUDIT
Interpret
DeepSeek reads intent; JEV audits it with closed options and confidence.
- 03CONFIRM
Confirm
Every field waits for human review; nothing executes without confirmation.
- 04MEMORY
Remember
Canonical memory with provenance and retrieval isolated by account, workspace and owner.
- 05BILLING
Bill
Sandbox billing loop: immutable quotes, idempotent webhooks and entitlements.
PROOF / WHAT IS ACTUALLY SHOWN
Evidence, not decoration.
The labels indicate whether the data was observed, comes from the artifact or belongs to the professional record of the case.
SCOPE / HONEST BOUNDARIES
What is demonstrated and what still needs validation.
A technical portfolio must also show where the available evidence ends.
- The pilot lives in staging: commercial billing stays off until external approvals exist —an explicit decision, not a forgotten to-do.
- JEV is a probabilistic evaluator: it audits, orders and lowers confidence; authority remains in code.
- No credentials or tenant data are published; the demo is shared with coordinated access.
CASE 10 / LÍA