Anthropic’s Claude Mythos Preview is restricted to ~40 vetted orgs via Project Glasswing, with evidence pointing to both genuine security concerns and acute compute constraints.
Key Takeaways
Mythos autonomously found real zero-day vulnerabilities in testing, not just reproduced known ones – Anthropic’s Frontier Red Team documented this as the threshold justifying restricted release.
Pricing is $25/$125 per million input/output tokens with a 1M token context window and 128K max output; Anthropic committed $100M in compute credits to Glasswing participants.
A leaked internal draft described Mythos as “expensive to run” alongside “not yet ready for general release” – the only document pairing cost and access restriction directly.
Anthropic’s compute situation in April 2026 was strained: CoreWeave gap-fill deal, Google/Broadcom TPU capacity not arriving until 2027, and ~$500M chip design initiative all announced within days of the Glasswing launch.
Restricting agentic harnesses simultaneously, citing “outsized strain on systems,” reinforces that capacity limits were a live operational concern during the same window.
Hacker News Comment Review
Commenters were split on whether the zero-day capability claims are genuinely novel or incremental over existing frontier models like ChatGPT Pro, with skeptics arguing Anthropic inflates vulnerability counts to create marketing hype.
The “too dangerous” framing is widely read as convenient for a pending IPO, with multiple commenters suggesting the narrative positions Anthropic favorably regardless of whether security or cost is the real driver.
One concise synthesis from the thread: both factors are probably true simultaneously, since the KV cache scaling that yields the emergent capability also drives the extreme serving cost.
Notable Comments
@wood_spirit: argues that if Mythos were truly transformative, Anthropic could charge enough to make it economical – failure to do so suggests it is only incrementally better than Opus 4.7.
@waynecochran: “The KV cache scaling yields both the emergent power and requires the enormous capacity” – frames security and cost as structurally linked, not competing explanations.
