Tibo 分享了 Codex 开启 1M 上下文的方法。不过我不是很有动力去修改，感觉当前还挺流畅的，我相信他们已经针对这个上下文调优过，
只要压缩得当，上下文短一些性能会更好也更便宜。

具体方法很简单，只要在 ~/.codex/config.toml 中设置：

Tibo (@thsottiaux)
Here is how to enable a 1M-token context window in Codex for GPT-5.6 Sol.

Even though we have tuned the context limit in Codex to be set optimally when it comes to performance and cost, this is a common ask, so here it is documented.

A larger context window lets Codex retain more code, tool output, and conversation history before summarizing older material. You need a model that supports it. And GPT-5.6 Sol, for example, has a documented 1,050,000-token window.

Open ~/.codex/config.toml and add or update these settings at the top level, before any [section] headers:

The first setting selects the model. The second tells Codex to use a one-million-token context budget. The third starts automatic history compaction around 900,000 tokens, leaving some headroom. Restart Codex client and start a new session after saving.

To try the configuration for a single CLI session without changing your defaults:

Have fun, but also know that we tuned the default carefully!