Claude Mythos and misguided open-weight fearmongering

Claude Mythos and misguided open-weight fearmongering

From Interconnects by Nathan Lambert

April 9, 2026 · 9 min

About this episode

The episode discusses the implications of the Claude Mythos model announcement and the surrounding narratives on open-weight AI models and cybersecurity.

With the announcement of the Claude Mythos model this week and the admittedly very strong stated abilities, especially in cybersecurity, a new wave of anti open-weight AI model narratives surged. The TL;DR of the argument is that our digital infrastructure will not be ready in time for an open-weight version of this model, which will allow attacks to be conducted by numerous parties. The backlash against open models in the wake of the Mythos news conflates too many general unknowns into a simple, broad policy recommendation that could actually further weaken cybersecurity readiness. We’ve been here before – open-weight models were discussed as being extremely dangerous when OpenAI withheld GPT-2 weights in 2019, and when OpenAI released GPT-4 in 2023. Both of these waves came and went. The core mistake that is being made is the composition of two issues: 1) the acceptance of the open-closed model gap being static in time and 2) linking open-weight viability generally to specific issues. I’ve written at length recently on how I think that the best, frontier-level open weight models are going to fall behind the best closed models in overall capabilities in the near future. I’ve…

People in this episode

Host: Nathan Lambert

Topics covered

  • AI models
  • cybersecurity
  • open-weight models
  • policy recommendations
  • technology trends

Keywords

  • Claude Mythos
  • open-weight models
  • cybersecurity
  • AI policy
  • OpenAI
  • GPT-2
  • GPT-4

Mentioned in this episode

Organizations: OpenAI

Products: Claude Mythos

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