Industrial adoption of post-training methods under live-system constraints

Establish how published post-training methods can be safely adopted on live, deployed systems while satisfying fixed-budget, regression-safety, and integration constraints, thereby closing the gap between post-training research and industrial practice.

Background

The paper characterizes industrial post-training as brownfield maintenance: teams begin with a deployed checkpoint, operate under fixed compute and mixture budgets, and must improve a targeted capability without degrading existing capabilities. In this setting, new data must displace or reweight existing data, synthetic-data generation is limited by the yield of usable supervision, and local mixture changes can produce non-local behavioral regressions.

Although the case study demonstrates a successful failure-driven-synthesis patch for competitive-programming code generation, the paper presents the broader unresolved issue as the gap between published research techniques and the practical requirements of safely integrating those techniques into a live system. The authors frame this as an engineering and methodological problem involving mixture accounting, yield measurement, probabilistic regression testing, efficient experimental design, and conservative patch integration.

References

None of the techniques we adopted is new, and that is the point: the open problem is the gap between research and practice, the constraints of adopting published methods safely on a live system.

— LLM Post-Training as Brownfield Maintenance: An Industrial Perspective on Dataware Engineering  (2608.31102 - Rajbahadur et al., 31 Aug 2026) in Section Conclusion, Section 5