1. Agreed w @scaling01 that Mythos appears to be better GPT 5.5 on many metrics. 2. Mythos is definitely a major wakeup call wrt security, a…

1. Agreed w @scaling01 that Mythos appears to be better GPT 5.5 on many metrics. 2. Mythos is definitely a major wakeup call wrt security, and will pose problems for real-world systems that aren’t well-defended. As @scaling01 says elsewhere a full release of it this point would cause a huge mess. 3. The big open question is how well Mythos does in open-ended real world problems. I don't understand how people are still coping about Mythos. Here's a few benchmarks: SWE-bench Pro: Mythos -> 77.8%, GPT-5.5 -> 58.6% HLE: Mythos -> 56.8%, GPT-5.5 -> 41.4% UK AISI cyber ranges: - "The Last Ones": Mythos -> 6/10, GPT-5.5 3/10 - "Cooling Tower": Mythos -> 3/10, G…

Source: Gary Marcus (X) | 2026-05-23