Will Claude Mythos or a similar model be publicly released before September 2026?

Prediction market on metaculus. Claude is a series of LLMs developed by Anthropic, a prominent American AI company focused on AI safety. Over the past year, Claude became popular due to its proficiency in software engineering tasks. According to [Wikipedia](https://en.wikipedia.org/wiki/Claude_\(language_model\)#Claude_Mythos): > The existence of a model named Claude Mythos had become publicly known on March 26 \[2026] due to leaked blog post drafts. On April 7, 2026, Anthropic announced \[that] a preview of Claude Mythos ("Project Glasswing/Claude Mythos Preview") would be made available to 11 companies and organizations to find and fix cybersecurity vulnerabilities. Anthropic has stated that it does not plan to make Claude Mythos Preview generally available. Anthropic said that Mythos is capable of finding critical vulnerabilities in major operating systems and web browsers. The UK AI Security Institute reported that Claude Mythos was able to solve a 32-step cyber range called "The Last Ones" 3 out of 10 times, becoming the first model to do so end-to-end. The next best models on this evaluation were Claude Opus 4.6, followed by a tie between GPT-5.4 and GPT-5.3 Codex. >   > Two weeks after the limited release, Mozilla announced that it had found and patched 271 security vulnerabilities in Firefox using Mythos Preview. Reportedly, a few users in a private Discord channel gained access to Mythos the same day it was announced, using details from the recent Mercor data breach. The NSA has also used Mythos, despite the fact that the DoD, its parent organization, had blacklisted Anthropic after a dispute. In April 2026, the Chinese government requested access to Mythos, but was rebuffed.

Resolves: 9/1/2026.