ResearchResearch paperReasoning & Planning · Reinforcement Learning · Efficiency & Inference1 source · Oct 21, 2026

Monitorability Is Trainable: Post-Training for Chain-of-Thought Monitorability

Chain-of-thought (CoT) monitoring is one of the few practical tools available for overseeing capable AI systems, but it is fragile: a model's reasoning is only useful to a monitor if it remains coupled to what the model actually does.

Key points

  • This coupling can be degraded during training through, for example, CoT compression, optimization against a monitor, and out-of-context generalization from synthetic documents.
  • In this work, we propose an unsupervised post-training objective based on maximizing mutual information between CoT and the output for improving CoT monitorability.
  • Applied to undegraded policies, it further improves judged monitorability, improves prediction of unsafe behavior by CoT monitors and activation probes, and increases the prevalence of consequential reasoning.
  • A dedicated monitorability post-training stage can extend current practices that protect CoT from direct optimization pressure.

Sources (1)

  • [1]Monitorability Is Trainable: Post-Training for Chain-of-Thought Monitorability
    arXiv (AI, ML, NLP, CV, robotics, multi-agent) · Oct 21, 01:35 PM
    Chain-of-thought (CoT) monitoring is one of the few practical tools available for overseeing capable AI systems, but it is fragile: a model's reasoning is only useful to a monitor if it remains coupled to what the model actually does.
    This coupling can be degraded during training through, for example, CoT compression, optimization against a monitor, and out-of-context generalization from synthetic documents.

Extractive summary: sentences quoted from the sources.

Before this

  1. Oct 21, 2026Mitigating Query Shortcuts in Chain-of-Thought with Context-Aware Decoding
  2. Oct 21, 2026A Large-Scale Evaluation of Role-Enhanced Zero-Shot Chain-of-Thought Prompting
  3. Oct 20, 2026Fine-tuning GPT-OSS-20B for multilingual reasoning on Amazon SageMaker HyperPod
  4. Oct 20, 2026PAR: Progress-Aligned Recurrence for Length Generalization in State Tracking
  5. Oct 20, 2026Answering in the User's Variety: Calibrated Accommodation Pairs for Post-Training
  6. Oct 19, 2026Honeypots for AI Agent Insider Threats

Related