OpenAI reduces Codex Model Context Size from 372k to 272k

This was tweeted about when it happened, with some explanation from Tibo here: https://x.com/thsottiaux/status/2076543065045795309

Context size cuts like this are usually a cost/latency tradeoff rather than a capability one - serving a smaller window is cheaper and keeps latency in check, and most sessions probably don't need anywhere near 372k tokens anyway. Curious if this affects people who were actually relying on the larger window for big codebases.

The other day I was trying to find out exactly how much context size 5.6 has in codex CLI (via subscription) and I didn’t find that documented in any of the obvious places. Sort of ridiculous that we have to find this out in X or Reddit, e.g:

https://www.reddit.com/r/codex/s/hVv29obfFD

> I never felt that context size was any issue at all in codex.

I'm guessing you just started using codex, it suffered greatly from "model context size exceeded" errors early on, where compaction couldn't even recover from it, these errors just stopped happening maybe some month(s) ago.

Nowadays it's a lot better though and I've don't get stuck in those anymore. Although I don't like the idea that they don't surface what goes into the "concise summary" afterwards, make it really hard to know if it actually got everything important or not.

In general, codex seems to be moving into the way of hiding as much from the user as possible, and it wouldn't surprise me if they eventually start encrypting the entire session logs just like they did with agent>sub-agent prompts recently. Sad though as it's easily the best harness+model combo available today out of the ones I've tried.

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