No need to panic just yet
Three reasons to think that yesterday’s Mythos announcement from Anthropic was overblown:
Where Tom Fridman worried in his Times column yesterday about kids accidentally blowing up the power grid…
… the actual system tested was given a much easier job than in real life, with “sandboxing” turned off, making it more of proof of concept than an immediate threat.
Philo Groves@PhiloGroves
Mythos' Firefox exploitation didn't actually have sandbox enabled and built on top of research from Opus. Shocker.
10:57 AM · Apr 9, 2026 · 83.4K Views
11 Replies · 55 Reposts · 651 Likes
Open-weight models can already do a fair amount of what Mythos can do, in a simplified preparation. Mythos is more sophisticated but perhaps not head-and-shoulders the way it was portrayed.
clem 🤗@ClementDelangue
"But here is what we found when we tested: We took the specific vulnerabilities Anthropic showcases in their announcement, isolated the relevant code, and ran them through small, cheap, open-weights models. Those models recovered much of the same analysis. Eight out of eight
6:58 PM · Apr 8, 2026 · 323K Views
70 Replies · 233 Reposts · 1.53K Likes
The model itself is incrementally better than previous recent models, but certainly not an off-the-chart breakthrough:
Ramez Naam@ramez
Anthropic's Mythos does not appear to show any acceleration of ECI. After normalizing Anthropic's internal ECI with @EpochAIResearch 's public ECI, it's clear that the two metrics are extremely close, and that Mythos is pretty much on trend, just slightly above GPT 5.4. /1
6:30 PM · Apr 8, 2026 · 132K Views
28 Replies · 65 Reposts · 578 Likes
To a certain degree, I feel that we were played. The demo was definitely proof of concept that we need to get our regulatory and technical house in order, but not the immediate threat the media and public was lead to believe.