Pitwall is a production system that generates natural-language Formula 1 strategy briefings in English, Spanish, and Portuguese by treating faithfulness as an architectural property. Every published sentence is decomposed into typed factual claims and verified against a probabilistic race state before output.
The system uses a vectorized Monte Carlo engine with N=2,000 per-lap continuations calibrated on 126 races from 2018-2024. Fine-tuning data is filtered so that only 81.9% of model-written targets, whose claims are fully state-supported, are retained.
End-to-end operation was confirmed at the Austria and Britain Grands Prix in 2026, with a timestamped probability trace correctly locking onto the winner ten laps before the flag.