Is Mythos too Dangerous?

Summary
Software engineer and streamer ThePrimeagen reacts to Anthropic’s announcement of Claude Mythos Preview, discussing its reported benchmark performance and cybersecurity capabilities. He examines community debate over whether Anthropic’s decision to withhold the model from general release is a genuine safety precaution or a marketing stunt, before reflecting on how advancing AI affects the relevance of traditional coding skills.

What is shown

• [01:29] Anthropic benchmark comparison chart showing SWE-bench Pro, Terminal-Bench 2.0, and SWE-bench Multimodal results for Mythos Preview versus Opus 4.6.
• [01:58] Extended benchmark listings displaying SWE-bench Multilingual and SWE-bench Verified scores.
• [02:05] Reasoning evaluation scores comparing Mythos Preview to Opus 4.6 on GPQA Diamond and Humanity’s Last Exam (with and without tools).
• [03:13] Anthropic report excerpt titled “The significance of Claude Mythos Preview for cybersecurity,” detailing discovered zero-days in OpenBSD, web browser sandboxes, Linux, and FreeBSD NFS.
• [04:19] Tweet from the official FFmpeg account thanking Anthropic for responsibly reporting patches under Project Glasswing.
• [04:43] Anthropic announcement text explaining why Claude Mythos Preview will not be generally released and outlining planned safeguards for upcoming Opus models.
• [05:45] Social media reactions on X regarding the model release decision from users @marketDepthX, Boris Cherny (@bcherny), Astraia Intel (@astraiaIntel), and Low Level (@LowLevelTweets).
• [09:52] Promotional segment for Terminal.shop coffee.

Claims & numbers

• The presenter shares Anthropic benchmark scores comparing Claude Mythos Preview against Opus 4.6:
  • SWE-bench Pro: 77.8% (Mythos Preview) vs. 53.4% (Opus 4.6) [01:33].
  • Terminal-Bench 2.0: 82.0% vs. 65.4% [01:35].
  • SWE-bench Multimodal (internal implementation): 59.0% vs. 27.1% [01:36].
  • SWE-bench Multilingual: 87.3% vs. 77.8% [01:58].
  • SWE-bench Verified: 93.9% vs. 80.8% [01:58].
  • GPQA Diamond: 94.6% vs. 91.3% [02:07].
  • Humanity’s Last Exam without tools: 56.8% vs. 40.0% [02:13].
  • Humanity’s Last Exam with tools: 64.7% vs. 53.1% [02:23].
  • CyberGym vulnerability reproduction: 83.1% [04:30].
• The presenter cites Anthropic’s report stating Mythos Preview identified zero-day vulnerabilities in every major operating system and browser, including a 27-year-old flaw in OpenBSD and a 16-year-old vulnerability in FFmpeg [03:15, 03:36, 04:17].
• The presenter highlights Anthropic’s statement that Claude Mythos Preview will not be made generally available due to cyber risk levels [04:46].

Notable quotes

• “We’ve been upgraded to Mythos, the greatest model to ever be dropped.” [00:13]
• “They called it Mythos because no one’s ever going to see it. They’re literally trying to rage bait us right now.” [06:28]
• “I’ve been able to abandon more projects than I have ever done in my lifetime thanks to the power of AI.” [09:41]

Assessment
This is an independent commentary and reaction video discussing Anthropic’s published announcements, benchmarks, and community reactions. The presenter does not demonstrate or run the model firsthand, as it remains unreleased to the general public.

Described by gemini-3.8-flash on 2026-09-29 from the video’s audio and frames.