Series
The architectural patterns of Series 1-3, rebuilt on the .NET runtime. Semantic Kernel, Microsoft.Extensions.AI, hosted agents, streaming.
You bet a year of roadmap on Semantic Kernel. Then Microsoft renamed the bet. Here is what actually changed, what did not, and why the architects who shrugged are the ones who read the contract instead of the brand.
Your senior dev has spent three days hand rolling wrapper classes for logging, caching, and provider switching around the OpenAI SDK. Microsoft already shipped that, called it boring, and put it in the box with the rest of .NET. Surprise.
🗓️ Last updated: August 2026 The architect inherits a brownfield .NET 10 service that classifies incoming customer-support emails into six ticket categories, extracts the order number if there is on
A pod restart took twenty three in flight agent runs to the grave, and not one came back, because the loop assumed its host process was immortal. The .NET hosting model solved this years ago. Your agent simply never asked it to.
The first token landed in 280 milliseconds and the user was already gone by the second one, tab closed, reading the real logs. The model kept generating anyway, billing you for a paragraph nobody will ever see. The fix is not the model. It is the pipe.
The whole service projected on the meeting room wall, sixty lines of host wire up, and a three month junior asking where the prompt template lives. If the answer takes longer than ninety seconds or needs a second file, the architecture already lost the review.
