3 Places Your .NET Chat Code Quietly Drops OpenAI's Encrypted Reasoning

Description and use

<p>The bug I want to talk about doesn't throw. Nothing turns red in the logs and no test fails. A reasoning model answers the first question well, and on the second turn it acts as if the first turn never happened. You blame the prompt, then the temperature, then the model. The real cause is usually one line in your own chat loop.</p> <p>Here's what's going on. When you call OpenAI's Responses API through <code>Microsoft.Extensions.AI</code> with a reasoning model, nothing stored on the server (<code>store=false</code>, or zero data retention) and encrypted reasoning requested, the response ca

Problem

<p>The bug I want to talk about doesn't throw. Nothing turns red in the logs and no test fails. A reasoning model answers the first question well, and on the second turn it acts as if the first turn never happened. You blame the prompt, then the temperature, then the model. The real cause is usually one line in your own chat loop.</p> <p>Here's what's going on. When you call OpenAI's Responses API through <code>Microsoft.Extensions.AI</code> with a reasoning model, nothing stored on the server (<code>store=false</code>, or zero data retention) and encrypted reasoning requested, the response ca

Outcome

<p>The bug I want to talk about doesn't throw. Nothing turns red in the logs and no test fails. A reasoning model answers the first question well, and on the second turn it acts as if the first turn never happened. You blame the prompt, then the temperature, then the model. The real cause is usually one line in your own chat loop.</p> <p>Here's what's going on. When you call OpenAI's Responses API through <code>Microsoft.Extensions.AI</code> with a reasoning model, nothing stored on the server (<code>store=false</code>, or zero data retention) and encrypted reasoning requested, the response ca

Evidence

3 Places Your .NET Chat Code Quietly Drops OpenAI's Encrypted Reasoning

Source