05·AI / ML
Infinity Broker
A white-label AI co-pilot for US luxury brokerages: a self-hosted, fine-tuned LLM running a tool-calling agent loop over real Miami-Dade County property records and a brokerage's own CRM inventory and leads. The pitch is the interface, not another data feed, one plain-language layer that reads across the MLS, CRM, and inbox tools a brokerage already pays for.
ResultA live, functional POC over three real public and first-party data sources, hardened by deterministic honesty guardrails (every figure traced to a real tool result, all arithmetic server-side) and a 169-test suite covering every regression found in live stress-testing.

Develop
What it took
Skills behind it.
Primary discipline plus the support stack.
Skills demonstrated
- AI & Machine LearningPrimary
Self-hosted Qwen3 fine-tune driving a multi-tool agent loop (county search, comps, buyer-matching, lead creation, alerts) with per-tool result pinning and a repeat-call loop break for reliability.
- Prompt EngineeringSecondary
The honesty layer: system-prompt tool-use contracts plus deterministic overrides that catch fabricated figures, system-prompt leakage, and follow-up chips that contradict the reply, where prompt-tuning alone proved unreliable.
- Backend EngineeringSecondary
Serverless tool loop on Vercel, Neon Postgres for persisted leads and hourly alert polling, and integrations to Miami-Dade GIS / Property Appraiser plus a RESO Web API MLS feed (bearer-auth path built, dataset pending).
- Product StrategySecondary
Repositioned the product away from 'another data source' (already commoditised by the MLS bundle) toward the orchestration layer, the one conversation across MLS + CRM + inbox.
- Frontend EngineeringSupporting
The white-label demo: team-switching chat over real records, a CRM pipeline dashboard, per-listing pages with an honest 'no photography on file' fallback, and a full-screen mobile chat takeover.
Develop · Forks
Decisions on the record.
The few calls worth defending. Each one is a fork; the other branch would have been a different project.
Decision · 01
Why deterministic guardrails, not just a better prompt
Every reliability problem this POC hit, a fabricated square-foot figure, a follow-up chip that re-asks what the reply just answered, the model reciting its own system prompt, came back the moment it depended on the model choosing to behave. The fix that held is a code-level pass that diffs the model's stated numbers against the real tool result and rewrites the reply from real data on a mismatch. Prompting sets the intent; deterministic overrides enforce it.
Decision · 02
Why a self-hosted fine-tune for the POC, Bedrock for production
The self-hosted Qwen3 fine-tune made the POC free to iterate on and fully private, the right call for finding out what the product even is. But its own measured tool-call reliability (~80% ceiling, worse under load) is the evidence for routing production reasoning through Claude on Bedrock instead, with the fine-tune demoted to narrow phase-2 tasks like copy and lead scoring.
Decision · 03
Why 'no photography on file', not stock imagery
County parcel records genuinely carry no listing photos, so the per-listing page shows an honest aerial-and-monogram fallback rather than a decorative stock photo that would imply data the record doesn't have. The same discipline runs through the whole product: a saved sample is labelled a sample, a disconnected capability is declined plainly. When the user is a broker, trust is the product.
Deliver
What shipped.
A live, functional POC over three real public and first-party data sources, hardened by deterministic honesty guardrails (every figure traced to a real tool result, all arithmetic server-side) and a 169-test suite covering every regression found in live stress-testing. MLS asking prices are the one piece still pending a brokerage's RESO credentials.
By the numbers
Automated tests
every live regression pinned
Live data sources
GIS parcels, appraiser, CRM
Warm response
chip suggestions decoupled
Frames
Selected from the work.
5 frames
01Landing and live demo 02CRM pipeline, in use 03CRM dashboard 04Per-listing page, honest no-photo fallback 05Mobile chat
