We replicated Mythos findings in opencode using public models, not Anthropic's private stack. The moat is moving from model access to valida…

We replicated Mythos findings in opencode using public models, not Anthropic's private stack. The moat is moving from model access to validation: finding vulnerability signal is getting cheaper; turning it into trusted security A better way to read Anthropic's Mythos release is not "one lab has a magical model." It is: the economics of vulnerability discovery are changing. We took the patched public Mythos examples and tried to reproduce them with GPT-5.4 and Claude Opus 4.6 in an open-source harness. Every run stayed below $30 per file. AI models are already good enough to narrow the search space, surface real leads, and sometimes recover the full root cause in battle-tested code. The takeaway: model access is not the moat anymore. Validation is. Finding vulnerability signal is getting cheaper; turning it into trusted security work is still hard. Co-authors: @KlaKlo_, Amadeusz, Marek, Kuba, Mikolaj UPDATE: We were able to replicate the Mythos findings using existing models (GPT5.4) Writeup coming early next week, no BS prompts, it's real reproduction

Source: Clem Delangue (X) | 2026-04-16