Curious about how Mythos — the model behind Anthropic's Project Glasswing — was finding decades-old bugs, I tried the same idea with what I already had: Codex 5.2 on medium reasoning, a small local RAG corpus of Linux kernel CVEs and C/C++ undefined-behavior notes, and a freshly cloned OpenBSD tree. After about 29 minutes of agent loops, it surfaced an unconditional pointer/length update after write() in send_data() — a write-error path that walks one byte before an mmap'd region. The fix landed upstream as a six-line guard. The lesson stayed the same: model quality matters, but context is king.