Stock Markets May 28, 2026 01:08 PM

Anthropic to expand access to Claude Mythos as it ships upgraded Claude Opus 4.8

Opus 4.8 improves honesty benchmarks while Mythos — a cybersecurity-focused LLM — is prepared for broader customer use

By Leila Farooq AMZN MSFT AAPL

Anthropic said it will make its advanced Claude Mythos model available to all customers in the coming weeks while simultaneously launching an updated Claude Opus 4.8. Mythos, noted for enhanced cybersecurity capabilities, has prompted concern among executives and world leaders. Opus 4.8 is being offered at the same price as the prior release and shows benchmark gains, especially in measures of honesty; early testers say it is more likely to flag uncertainty and less likely to assert unsupported claims.

Anthropic to expand access to Claude Mythos as it ships upgraded Claude Opus 4.8
AMZN MSFT AAPL

Key Points

  • Anthropic will make the Claude Mythos model available to all customers in the coming weeks; Mythos is noted for advanced cybersecurity capabilities.
  • Under Project Glasswing, companies such as Amazon, Microsoft and Apple are allowed to use Mythos for cybersecurity purposes.
  • Anthropic is releasing Claude Opus 4.8 at the same price as the previous Opus model, with reported benchmark improvements, particularly in honesty and handling uncertainty.

Anthropic announced on Thursday that it will roll out its powerful Claude Mythos model to all customers within the coming weeks, even as the company releases an upgraded Claude Opus 4.8.

Mythos is Anthropic's large language model designed with advanced cybersecurity features. The model's capabilities have prompted concern among corporate executives and world leaders about its potential effects. Under Project Glasswing, select major technology firms - including Amazon, Microsoft and Apple - have permission to use Mythos specifically for cybersecurity purposes.

Separately, Anthropic said it is launching Claude Opus 4.8 as an update to its Opus line. The company said Opus 4.8 will carry the same price as the preceding Opus model. Anthropic reported that the new release performs better across a range of benchmarks, with the most notable gains in honesty metrics.

Early testers of Opus 4.8 told Anthropic that the model is more inclined to signal uncertainty about its outputs and less prone to make claims without sufficient support. The company framed those improvements as addressing a common weakness in AI: models that "sometimes jump to conclusions, confidently claiming to have made progress in their work despite the evidence being thin," the Claude maker said.

The announcement combines two parallel moves: a broader customer rollout for a model with significant cybersecurity emphasis, and an iterative improvement to Anthropic's Opus series that targets reliability and truthful behavior at parity pricing. The timing places both products in the market concurrently, with Mythos positioned for selective use by major tech firms under Project Glasswing and Opus 4.8 positioned as the next standard Opus-tier offering.

Details in the company's statement highlight the focus on reducing unsupported assertions by the model and increasing its tendency to acknowledge uncertainty. Beyond those points, the company has not provided additional specifics in the announcement about long-term deployment schedules or changes to access policies beyond the coming weeks timeline for Mythos.

Risks

  • Mythos's advanced cybersecurity capabilities have generated concern among executives and world leaders about its potential impact on security and governance - this affects the technology and cybersecurity sectors.
  • General limitations of AI models include a tendency to make unsupported claims; Anthropic emphasizes Opus 4.8 reduces that behavior but the broader challenge remains - this impacts software reliability and enterprise AI adoption.
  • The announcement provides a timeline of "coming weeks" for Mythos rollout but lacks precise scheduling details, creating uncertainty for customers planning integration or security testing - this affects cloud and enterprise IT procurement cycles.

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