_version_ 1866911360301924352
author Cunningham, Hoagy
Wei, Jerry
Wang, Zihan
Persic, Andrew
Peng, Alwin
Abderrachid, Jordan
Agarwal, Raj
Chen, Bobby
Cohen, Austin
Dau, Andy
Dimitriev, Alek
Gilson, Rob
Howard, Logan
Hua, Yijin
Kaplan, Jared
Leike, Jan
Lin, Mu
Liu, Christopher
Mikulik, Vladimir
Mittapalli, Rohit
O'Hara, Clare
Pan, Jin
Saxena, Nikhil
Silverstein, Alex
Song, Yue
Yu, Xunjie
Zhou, Giulio
Perez, Ethan
Sharma, Mrinank
author_facet Cunningham, Hoagy
Wei, Jerry
Wang, Zihan
Persic, Andrew
Peng, Alwin
Abderrachid, Jordan
Agarwal, Raj
Chen, Bobby
Cohen, Austin
Dau, Andy
Dimitriev, Alek
Gilson, Rob
Howard, Logan
Hua, Yijin
Kaplan, Jared
Leike, Jan
Lin, Mu
Liu, Christopher
Mikulik, Vladimir
Mittapalli, Rohit
O'Hara, Clare
Pan, Jin
Saxena, Nikhil
Silverstein, Alex
Song, Yue
Yu, Xunjie
Zhou, Giulio
Perez, Ethan
Sharma, Mrinank
contents We introduce enhanced Constitutional Classifiers that deliver production-grade jailbreak robustness with dramatically reduced computational costs and refusal rates compared to previous-generation defenses. Our system combines several key insights. First, we develop exchange classifiers that evaluate model responses in their full conversational context, which addresses vulnerabilities in last-generation systems that examine outputs in isolation. Second, we implement a two-stage classifier cascade where lightweight classifiers screen all traffic and escalate only suspicious exchanges to more expensive classifiers. Third, we train efficient linear probe classifiers and ensemble them with external classifiers to simultaneously improve robustness and reduce computational costs. Together, these techniques yield a production-grade system achieving a 40x computational cost reduction compared to our baseline exchange classifier, while maintaining a 0.05% refusal rate on production traffic. Through extensive red-teaming comprising over 1,700 hours, we demonstrate strong protection against universal jailbreaks -- no attack on this system successfully elicited responses to all eight target queries comparable in detail to an undefended model. Our work establishes Constitutional Classifiers as practical and efficient safeguards for large language models.
format Preprint
id arxiv_https___arxiv_org_abs_2601_04603
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Constitutional Classifiers++: Efficient Production-Grade Defenses against Universal Jailbreaks
Cunningham, Hoagy
Wei, Jerry
Wang, Zihan
Persic, Andrew
Peng, Alwin
Abderrachid, Jordan
Agarwal, Raj
Chen, Bobby
Cohen, Austin
Dau, Andy
Dimitriev, Alek
Gilson, Rob
Howard, Logan
Hua, Yijin
Kaplan, Jared
Leike, Jan
Lin, Mu
Liu, Christopher
Mikulik, Vladimir
Mittapalli, Rohit
O'Hara, Clare
Pan, Jin
Saxena, Nikhil
Silverstein, Alex
Song, Yue
Yu, Xunjie
Zhou, Giulio
Perez, Ethan
Sharma, Mrinank
Cryptography and Security
Artificial Intelligence
We introduce enhanced Constitutional Classifiers that deliver production-grade jailbreak robustness with dramatically reduced computational costs and refusal rates compared to previous-generation defenses. Our system combines several key insights. First, we develop exchange classifiers that evaluate model responses in their full conversational context, which addresses vulnerabilities in last-generation systems that examine outputs in isolation. Second, we implement a two-stage classifier cascade where lightweight classifiers screen all traffic and escalate only suspicious exchanges to more expensive classifiers. Third, we train efficient linear probe classifiers and ensemble them with external classifiers to simultaneously improve robustness and reduce computational costs. Together, these techniques yield a production-grade system achieving a 40x computational cost reduction compared to our baseline exchange classifier, while maintaining a 0.05% refusal rate on production traffic. Through extensive red-teaming comprising over 1,700 hours, we demonstrate strong protection against universal jailbreaks -- no attack on this system successfully elicited responses to all eight target queries comparable in detail to an undefended model. Our work establishes Constitutional Classifiers as practical and efficient safeguards for large language models.
title Constitutional Classifiers++: Efficient Production-Grade Defenses against Universal Jailbreaks
topic Cryptography and Security
Artificial Intelligence
url https://arxiv.org/abs/2601.04603