OpenAI shipped GPT-6 Astra on September 3, 2026. Before wiring it into a .NET project, here's the actual API contract — context window, pricing, reasoning effort — checked against the live docs, plus what I found installing the real OpenAI NuGet package: the stable client can't do Astra's tool calling at all, the client that can is still experimental, and the SDK's named reasoning levels stop short of what the model documents.

OpenTelemetry gets the HTTP half of a distributed trace right automatically: two services, one trace, zero manual wiring. The interesting failure is one hop further, the moment the same request crosses into a queue. Two real ASP.NET Core services, a trace captured in Jaeger, and the exact boundary where context silently stops propagating unless you carry it across yourself.

Both .NET 8 and .NET 9 stop getting security patches on November 10, 2026 — same date, despite one being LTS and the other STS. Bumping TargetFramework takes five seconds. Finding out what changed underneath it takes longer: EF Core's query translation, whether one failing BackgroundService blocks every other one from starting, and how SQLite reinterprets a DateTimeOffset it's never seen before. I ran every item on this list myself, on both SDKs side by side, before writing any of it down.

Stable Chat Completions, the Microsoft.Extensions.AI bridge, and the still-experimental Responses API against GPT-6 Astra, side by side behind one CLI arg each. Companion repo for the article.

A Pomodoro-style focus timer with task tracking, visual themes, and premium features like Spotify playback and a productivity calendar. Backend on .NET with Supabase, subscription checks handled server-side.

Before/after demo for migrating enterprise .NET apps to modern .NET — async, DI, EF Core Code First, Polly v8, health checks, Serilog, and the Strangler Fig pattern. Companion repo for the article.