Anthropic framed Mythos and Project Glasswing as proof that frontier AI vulnerability research now needs gated access. We tested the public, patched cases with GPT-5.4 and Claude Opus 4.6 and found that the key building blocks are already accessible outside Glasswing, while reliable operationalization remains the real moat.

Anthropic presents Mythos and Project Glasswing as evidence that advanced AI vulnerability research should be restricted. But our replication suggests a different conclusion: the capabilities Anthropic points to are already available in public models, so defenders should prepare for that reality instead.