The lack of encrypted content support in the Chat Completions API is a huge headache for some of us. The Response API is great for some situations, but it’s not universally better.
I don’t understand why it can’t be added; when you use reasoning.encrypted_content , the request becomes stateless, meaning the Responses API is a bit pointless.
Related to `n` support for Responses API?.
Chat Completions doesn’t have an out-of-band method of passing a conversation history with different items or events. It would take a convolution of the format along the lines of new role messages, and new parameters to “include” something like summaries and reasoning that would break all existing code.
Almost like a new API endpoint. Voila!
But one that is not a step back in features and a huge code burden that yet treats the developer as an untrusted party that is a consumer of tool products that need nanny instructions that cannot be controlled. And features that need biometric scans and government IDs in order to get “dangerous” streaming messages.
reasoning.encrypted_content disables storing the conversation history. There is no “out-of-band” method used with the Responses API when you use reasoning.encrypted_content; that is the whole point of it.
OpenAI has literally added multiple new role types to messages before. e.g. tool and developer did not used to exist.
Any client that cannot handle the reasoning response fields could just… not add the optional "include": ["reasoning.encrypted_content"] field to their Chat Completion API request. If you include an optional parameter that breaks your code, then you should probably ask gpt-4.1-nano-2025-04-14 for help.