Make Constitution → Create dataset based on rubric and train classifier
Constitutional Classifier++: Linear probe
Holds up relatively well even against adaptive attacks unlike Gemini Probe
The first-generation classifier reduced jailbreak success rate from 86% → 4.4%, but introduced drawbacks: +23.7% computational cost and increased false rejection of benign queries. The new system uses a two-stage cascade architecture: a lightweight linear probe based on internal activations acts as the first filter, screening all traffic.
Only suspicious cases are escalated to a more powerful exchange classifier that examines both input and output. Additional computational cost: ~1%. False rejection rate for benign queries: 0.05% (87% reduction vs. previous). No universal jailbreaks discovered yet. By leveraging internal activations, the system is more robust against output obfuscation and reconstruction attacks, and works complementarily with external classifiers.

Seonglae Cho
