The Claude Agent SDK (the package that turns Claude into an autonomous coding agent with tools, permissions, and a conversation loop) only ships officially for Python and TypeScript. In C#, the closest thing is buried inside the regular Anthropic SDK: a `ToolRunner` helper that drives the tool-use loop for you. Here's how to build a real file-editing, command-running agent with it, and where the unofficial alternatives fit.

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.

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.