Codex CLI 0.153.0 adds a context mode that throws the window away instead of summarizing it.

Released September 3, features.context_management.experimental_mode is off by default and, when enabled for eligible ChatGPT Plus/Pro/Pro Lite sessions on the Codex backend, activates token-budget context, history notes, and a new_context tool letting the model request a fresh window without spending tokens on a compaction summary. API-key sessions, custom providers and temporary structured threads are excluded. Every other harness bets on better summarization; this bets that a clean window beats a compressed one. Same release adds remote plugin marketplaces (#42150) and makes Guardian review history survive compaction, restarts and user-created forks.