Why did Anthropic hold back Mythos?

The transcript discusses Mark Andreessen's theory about why Anthropic chose to hold back its Mythos AI model from commercial release. According to Andreessen, the primary driver was likely financial and logistical: Mythos was an extremely large and expensive model to serve, estimated at 10 to 20 times the token cost of Opus. With Opus 4.7 already in the pipeline, Anthropic may have made a strategic decision to withhold Mythos to conserve compute resources for the next generation model rather than strain infrastructure on an already-oversized release.

The speaker also notes that the withholding of Mythos generated an unintended — or perhaps intentional — marketing benefit. By framing the decision around safety and responsibility, particularly given that Mythos reportedly revealed previously unknown coding vulnerabilities, Anthropic created an impression of altruism and scarcity. Government officials and the broader public interpreted the decision as a bold, principled safety stance, turning the non-release into a major public relations event.

The speaker acknowledges that the altruistic framing may not be entirely cynical — Mythos genuinely did expose dormant security vulnerabilities in codebases, and giving organizations time to patch those issues before the model's capabilities became widely accessible is a legitimate safety rationale. Nonetheless, the speaker concludes that the compute economics likely made commercial release impractical regardless, suggesting the safety narrative and the business reality conveniently aligned in Anthropic's favor.