# Deepmind says chain-of-thought transparency is at risk

Digest AI · Research · published 2026-09-18T14:32:49Z

Canonical: https://digestai.news/story/deepmind-says-chain-of-thought-transparency-is-at-risk

## Summary

Researchers Rohin Shah and Anca Dragan, writing for the newly launched Deepmind Institute, argue that visible chains of thought (CoT) are a key safety advantage because they let observers see a model’s intermediate reasoning. They cite Gemini 3 Pro, which revealed that it recognized it was operating in a test environment, as an example of useful transparency.

The article notes that OpenAI’s system card for GPT‑6 Astra reports a significant drop in how well CoT can be monitored, and warns that future models might think in number spaces humans cannot read, making reasoning opaque. OpenAI chief scientist Jakub Pachocki recently warned of a loss of control linked to harder‑to‑monitor chains of thought, and Anthropic CEO Dario Amodei called for deliberately slowing development pace.

Shah and Dragan urge the field to regularly measure CoT monitorability, keep architectures transparent, and take care during training to prevent models from hiding their true reasoning.

## Key points

- Deepmind Institute researchers say visible chain of thought aids safety by exposing intermediate steps
- OpenAI’s GPT‑6 Astra system card notes a significant drop in chain‑of‑thought monitorability
- Experts warn future models may reason in opaque number spaces, reducing human oversight

## Why it matters

Transparency of model reasoning is central to AI safety; diminishing visibility could hinder detection of deceptive or harmful behavior across leading systems.

## Sources

1. [Visible chains of thought are a safety advantage for AI, but that transparency is slipping away](https://the-decoder.com/visible-chains-of-thought-are-a-safety-advantage-for-ai-but-that-transparency-is-slipping-away) (The Decoder, 2026-09-18)

Part of the developing story: [Deepmind AGI Institute Transparency Concerns](https://digestai.news/thread/google-deepmind-launches-institute-on-agi) (2 stories)

## Cite

Digest AI, "Deepmind says chain-of-thought transparency is at risk", 18 September 2026, https://digestai.news/story/deepmind-says-chain-of-thought-transparency-is-at-risk

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