> 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.

For me, Codex regularly forgets to complete its last task when compaction occurs, especially when the last message I sent was right before compaction.

Most problems should be divide-and-conquerable into chunks that 300 vs 400k context is basically never an issue. A coding agent isn't an infinite chat.