"Will It Mythos?" benchmark of AI vulnerability finding

Category: Pulse
Status: discussion
Sources: swelljoe.com, discussion
Summary: An independent benchmark post (Joe, swelljoe.com, dated 2026-05-30 with updates through 2026-06-22) tests whether Claude Mythos is uniquely strong at finding security vulnerabilities or whether its restriction is mainly economic. The author reports Mythos found four bugs no other model caught, but argues public models could plausibly find them with better prompts or tooling, and that several cheaper models (Qwen 3.6, DeepSeek, MiMo) were competitive with Opus 4.8 and GPT-5.5 at roughly an order of magnitude lower cost. The author flags sparse data and single runs per case as limitations.
Comments: The thread (about 249 points) ties into the contested Mythos export-control claims tracked in follow-ups; commenters debated whether vulnerability-finding capability is a genuine model differentiator or a function of prompting, tooling, and budget.
Why it matters: It adds an independent data point to the AI-found-vulnerability debate around Mythos and OpenAI's Daybreak, where capability claims have outrun reproducible method.