Bayesian Control for Coding Agents

Theodore Papamarkou, Vladislav Smirnov, Viktor Mazanov, Artem Vazhentsev, Preslav Nakov, Timothy Baldwin, Artem Shelmanov


Abstract
Modern coding agents pair LLM generators with various tools, including cheap diagnostics and expensive verifiers. The tool-use decisions are typically governed by orchestrators that often use fixed rules and ignore uncertainty. We formulate orchestration as cost-sensitive sequential hypothesis testing: a Bayesian controller maintains a belief over candidate correctness and dynamically decides whether to gather more evidence, refine the candidate, verify it, or stop. Across six generators and nine coding benchmarks, Bayesian control proves to be most valuable when verification is costly and critics are informative but imperfect. Beyond control, the belief state yields an interpretable correctness score that outperforms token-probability and raw tool-success baselines for uncertainty quantification.
Anthology ID:
2026.emnlp-main.1548
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
35299–35341
Language:
URL:
https://aclanthology.org/2026.emnlp-main.1548/
DOI:
Bibkey:
Cite (ACL):
Theodore Papamarkou, Vladislav Smirnov, Viktor Mazanov, Artem Vazhentsev, Preslav Nakov, Timothy Baldwin, and Artem Shelmanov. 2026. Bayesian Control for Coding Agents. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 35299–35341, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Bayesian Control for Coding Agents (Papamarkou et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.1548.pdf