Codex client crash: "Unknown parameter: prompt_cache_retention" during context compaction (blocking issue)

Hello,

I’m encountering a consistent blocking issue with the Codex client that makes it impossible to continue working after some time.

:red_circle: Problem description

At a certain point (likely when the context becomes large), Codex attempts to run a context compaction task and fails with the following error:

Error running remote compact task:
{
  "error": {
    "message": "Unknown parameter: 'prompt_cache_retention'.",
    "type": "invalid_request_error",
    "param": "prompt_cache_retention",
    "code": "unknown_parameter"
  }
}

After this happens:

  • the session becomes unusable

  • further interaction is not possible

  • restarting the same session does not recover it


:gear: What I’ve already tried

  • fully clearing local Codex caches and config directories

  • reinstalling the Codex client

  • starting new sessions

  • reducing context size manually

None of these steps resolved the issue.


:brain: Observations

  • The error occurs specifically during the remote context compaction step

  • It appears that the Codex client is sending a deprecated or unsupported parameter (prompt_cache_retention)

  • This suggests a mismatch between the Codex client and the current API


:police_car_light: Impact

This is a blocking issue:

  • it breaks long-running workflows

  • makes Codex unreliable for real-world usage

  • requires restarting sessions frequently (losing context)


:red_question_mark: Questions

  1. Is this a known issue with Codex context compaction?

  2. Is there a way to disable or bypass the compaction step?

  3. Is a client update required, or is there a workaround available?

Version 26.409.20454 (1462)

Same Codex app errors on compaction - #2 by nickzsb.nz

I’m seeing a new bug today that is occurring frequently when the application does auto compaction.

Version 26.409.20454 (1462)

26.4.1 (25E253)

Same thing, bro) I think this is a system problem

I’ve just started experiencing the same error.

Same problem today, subscribing

This issue is now fixed.