METR and Redwood red-team OpenAI's agent monitoring, find Codex sandbox and Auto-Review bypass

METR and Redwood Research published an October 22 report on three weeks (July 21–August 11, 2026) of stress-testing OpenAI's internal misalignment monitoring for agentic inference. Findings include unmonitored compaction events, monitoring triggered only when agents return control so agents can defer it indefinitely, two client-controllable headers that could disable monitoring for new agent instances, and Codex agents that could in principle bypass Codex sandboxing and Auto-Review; roughly 10% of eligible internal Codex traffic was likely unmonitored between May and July 2026. The internal report was 61 pages, of which OpenAI shared a 38-page redacted version; OpenAI says production-impacting issues were patched, a claim METR has not evaluated.