Aletheia: What Makes RLVR For Code Verifiers Tick?

Fuente: arXiv
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Main Authors: Venkatkrishna, Vatsal, Paul, Indraneil, Gurevych, Iryna
Format: Preprint
Published: 2026
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author Venkatkrishna, Vatsal
Paul, Indraneil
Gurevych, Iryna
author_facet Venkatkrishna, Vatsal
Paul, Indraneil
Gurevych, Iryna
contents Multi-domain thinking verifiers trained via Reinforcement Learning with Verifiable Rewards (RLVR) are a cornerstone of modern post-training. However, their adoption in code generation has lagged behind execution feedback due to the prohibitive costs of the full RLVR pipeline. In this work, we ablate three primary drivers of RLVR performance and cost: intermediate thinking traces, learning from negative samples, and on-policy training. We introduce Aletheia, a controlled, execution-grounded testbed to facilitate a contamination-free analysis of code verifiers across disparate model sizes and covariate shifts. Our analysis reveals that the optimal training recipe is scale-dependent: on-policy learning is the primary performance driver for small verifiers, whereas thinking traces become the most vital factor for larger sizes. Furthermore, we show that negative samples stabilize training at large sizes, and scaling inference-time compute cannot compensate for any core RLVR component. These findings provide a compute-optimal roadmap for practitioners, offering concrete strategies to simplify verifier training based on model size. Consequently, our work establishes a foundation for scalable supervision, enabling efficiently trained code verifiers to reliably supervise much larger code generation policies.
format Preprint
id arxiv_https___arxiv_org_abs_2601_12186
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Aletheia: What Makes RLVR For Code Verifiers Tick?
Venkatkrishna, Vatsal
Paul, Indraneil
Gurevych, Iryna
Software Engineering
Artificial Intelligence
Multi-domain thinking verifiers trained via Reinforcement Learning with Verifiable Rewards (RLVR) are a cornerstone of modern post-training. However, their adoption in code generation has lagged behind execution feedback due to the prohibitive costs of the full RLVR pipeline. In this work, we ablate three primary drivers of RLVR performance and cost: intermediate thinking traces, learning from negative samples, and on-policy training. We introduce Aletheia, a controlled, execution-grounded testbed to facilitate a contamination-free analysis of code verifiers across disparate model sizes and covariate shifts. Our analysis reveals that the optimal training recipe is scale-dependent: on-policy learning is the primary performance driver for small verifiers, whereas thinking traces become the most vital factor for larger sizes. Furthermore, we show that negative samples stabilize training at large sizes, and scaling inference-time compute cannot compensate for any core RLVR component. These findings provide a compute-optimal roadmap for practitioners, offering concrete strategies to simplify verifier training based on model size. Consequently, our work establishes a foundation for scalable supervision, enabling efficiently trained code verifiers to reliably supervise much larger code generation policies.
title Aletheia: What Makes RLVR For Code Verifiers Tick?
topic Software Engineering
Artificial Intelligence
url https://arxiv.org/abs/2601.12186