Welcome to the developer community, @JD42 — and thank you for the clear report and detailed repro.
Based on the current documentation, there does appear to be some inconsistency here.
The reasoning guide states:
Different models support different reasoning summary settings. For example, our computer use model supports the
concisesummarizer, while o4-mini supportsdetailed. To access the most detailed summarizer available for a model, set the value of this parameter toauto.autowill be equivalent todetailedfor most reasoning models today, but there may be more granular settings in the future.
At the same time, the API reference says:
summary: optional
"auto"or"concise"or"detailed"A summary of the reasoning performed by the model. This can be useful for debugging and understanding the model’s reasoning process. One of
auto,concise, ordetailed.
conciseis supported forcomputer-use-previewmodels and all reasoning models aftergpt-5.
Given your example and the fact that auto and detailed are still working while concise is returning an empty summary=[], this looks like it’s worth investigating further. I’m going to take a closer look and follow up here once I have more clarity.
UPDATE
I was able to reproduce this issue on my end. Reasoning summaries are returning empty on models gpt-5.2, gpt-5.4, and gpt-5.4-mini when summary is set to concise. I’ve forwarded this to the team at OpenAI.
Thanks again for flagging it.