# Top\_p problem when running gpt-5.2 API **URL:** \ **Category:** API\ **Created:** [December 12, 2025, 8:17pm UTC](https://community.openai.com/t/top-p-problem-when-running-gpt-5-2-api/1369144 "2025-12-12T20:17:18Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![DjSilver](https://sea2.discourse-cdn.com/openai1/user_avatar/community.openai.com/djsilver/32/448373_2.png) [@DjSilver](https://community.openai.com/u/DjSilver)\ **Post date:** [December 12, 2025, 8:17pm UTC](https://community.openai.com/t/top-p-problem-when-running-gpt-5-2-api/1369144/1 "2025-12-12T20:17:18Z")
Hey, I’m having some problems when I’m trying to run my prompt that is saved on “Chats“ and I have my script running with Powershell. But after changing the settings from gpt-5.1 to gpt-5.2 I also changed from reasoning high to xhigh. And I keep on getting this message, both in powershell and in the chat where I have my prompts saved on the dashboard. Unsupported parameter: ‘top\_p’ is not supported with this model. But I don’t have anything with top\_p in my prompt or script. But when I change to reasoning none, than it works, but no reasoning just makes my prompt weak and I can’t use it like that. So help med please. ---
**Author:** ![Foxalabs](https://sea2.discourse-cdn.com/openai1/user_avatar/community.openai.com/foxalabs/32/738355_2.png) [@Foxalabs](https://community.openai.com/u/Foxalabs)\ **Post date:** [December 12, 2025, 8:19pm UTC](https://community.openai.com/t/top-p-problem-when-running-gpt-5-2-api/1369144/2 "2025-12-12T20:19:06Z")
Hi there! This is a known issue and has been reported! ---
**Author:** ![DjSilver](https://sea2.discourse-cdn.com/openai1/user_avatar/community.openai.com/djsilver/32/448373_2.png) [@DjSilver](https://community.openai.com/u/DjSilver)\ **Post date:** [December 12, 2025, 10:17pm UTC](https://community.openai.com/t/top-p-problem-when-running-gpt-5-2-api/1369144/3 "2025-12-12T22:17:06Z")
Okay thanks. I just thought there was anything wrong with my prompt, I have even troubleshooted it with gpt-5.2 extended thinking uploading all documents. But there was no problem. So, I was going crazy. haha ---
**Author:** ![jay.li](https://avatars.discourse-cdn.com/v4/letter/j/35a633/32.png) [@jay.li](https://community.openai.com/u/jay.li)\ **Post date:** [December 13, 2025, 2:57am UTC](https://community.openai.com/t/top-p-problem-when-running-gpt-5-2-api/1369144/4 "2025-12-13T02:57:03Z")
And it occurs when using `agent.prompt`. If `agent.instructions` is used, it works normally ---
**Author:** ![hicham\_BAGUI](https://sea2.discourse-cdn.com/openai1/user_avatar/community.openai.com/hicham_bagui/32/524450_2.png) [@hicham\_BAGUI](https://community.openai.com/u/hicham_BAGUI)\ **Post date:** [January 19, 2026, 4:48pm UTC](https://community.openai.com/t/top-p-problem-when-running-gpt-5-2-api/1369144/5 "2026-01-19T16:48:14Z")
for a workaround try adding temperature=1 top\_p=1 ---
**Author:** ![\_j](https://sea2.discourse-cdn.com/openai1/user_avatar/community.openai.com/_j/32/766292_2.png) [@\_j](https://community.openai.com/u/_j)\ **Post date:** [January 19, 2026, 5:38pm UTC](https://community.openai.com/t/top-p-problem-when-running-gpt-5-2-api/1369144/6 "2026-01-19T17:38:16Z")
> [@hicham\_BAGUI](#): > > for a workaround try adding There is no workaround needed any more. And what you say is bad advice. Reasoning models do _not_ accept sampling parameters such as temperature or top\_p. The issue was that the “prompts” system, storing a preset for Responses to use (with a bad name) was sending an untolerated value “1” for top-p, which was not being accepted, because the internal default for gpt-5.2 is actually `0.98`. This was a backend issue. ---
**Author:** ![hicham\_BAGUI](https://sea2.discourse-cdn.com/openai1/user_avatar/community.openai.com/hicham_bagui/32/524450_2.png) [@hicham\_BAGUI](https://community.openai.com/u/hicham_BAGUI)\ **Post date:** [January 31, 2026, 8:34pm UTC](https://community.openai.com/t/top-p-problem-when-running-gpt-5-2-api/1369144/7 "2026-01-31T20:34:30Z")
I can confirm the issue has not been resolved, the value was forced to be sent even if you remove it from the config file, I hope we wont need a workaround soon, but thats still an issue and the only way I was able to you it is by sending the top\_p=1