# .NET Blog Free. Cross-platform. Open source. A developer platform for building all your apps. This is one page of public article previews, not the complete archive. Follow Next page to continue. Summaries are not the original full articles. ## Build Your Own AI Agent Harness in C#, the MafClaw Live Series DevFeed: [Build Your Own AI Agent Harness in C#, the MafClaw Live Series]() Original publisher: [Read original article]() Author: Bruno Capuano Published: 2026-09-16T21:00:00Z Content type: tutorial Language: en Sources: [.NET Blog]() Topics: [Agent Harness](), [Microsoft Agent Framework](), [AI Agent](), [C#](), [.NET]() Tags: [agent](), [agent-framework](), [agent-harness](), [ai](), [building](), [c-sharp](), [cloud](), [csharp](), [microsoft-agent-framework](), [microsoft-reactor](), [net](), [observability]() ### AI overview This article introduces a four-part live series that builds a complete C# AI agent using the Microsoft Agent Framework harness. It describes adding tools, planning, file access, approvals, memory, skills, shell commands, code execution, background agents, observability, governance, evaluations, and hosted deployment. ### Source excerpt I am building a complete C# agent live, from a single call around an IChatClient to a production-ready, observable, governed agent, using the Microsoft Agent Framework harness in a 4-part Microsoft Reactor series. The post Build Your Own AI Agent Harness in C#, the MafClaw Live Series appeared first on .NET Blog. ## Performance Improvements in .NET 11 DevFeed: [Performance Improvements in .NET 11]() Original publisher: [Read original article]() Author: Stephen Toub - MSFT Published: 2026-09-15T12:00:00Z Content type: article Language: en Sources: [.NET Blog]() Topics: [.NET](), [.NET 11]() Tags: [blog](), [improvements](), [net](), [net-11](), [performance](), [post]() ### AI overview This post surveys hundreds of performance improvements in .NET 11, including runtime and library changes that reduce bounds checks, allocations, locks, loop cycles, redundant checks, instructions, system calls, and array-copy costs. ### Source excerpt Take a tour through hundreds of performance improvements in .NET 11. The post Performance Improvements in .NET 11 appeared first on .NET Blog. ## Share your .NET story with the community DevFeed: [Share your .NET story with the community]() Original publisher: [Read original article]() Author: Luis Quintanilla Published: 2026-09-14T17:05:00Z Content type: article Language: en Sources: [.NET Blog]() Topics: [.NET](), [.NET Conf](), [Development]() Tags: [2026](), [blog](), [community](), [conference](), [customer-stories](), [developer-stories](), [developers](), [development](), [modernization](), [net](), [net-conf](), [performance](), [post](), [virtual-event]() ### AI overview Microsoft invites teams to share how they use .NET to solve practical problems for possible inclusion in .NET Conf 2026 and other .NET channels. Submissions may describe applications, system modernization, performance, security, efficiency, modern C#, or practical AI-powered capabilities. ### Source excerpt Share how your team uses .NET to solve real problems and help us bring more community stories to .NET Conf 2026 and other .NET channels. The post Share your .NET story with the community appeared first on .NET Blog. ## Use C# unions and closed hierarchies in ASP.NET Core DevFeed: [Use C# unions and closed hierarchies in ASP.NET Core]() Original publisher: [Read original article]() Author: Dmitrii Korolev Published: 2026-09-10T17:00:00Z Content type: tutorial Language: en Sources: [.NET Blog]() Topics: [C# 15](), [ASP.NET Core](), [.NET](), [Polymorphism]() Tags: [asp-net-core](), [blazor](), [c-sharp](), [c-sharp-15](), [closed-hierarchies](), [json](), [minimal-api](), [mvc](), [net](), [net-11](), [openapi](), [polymorphism](), [signalr](), [system-text-json](), [union-types]() ### AI overview Explains how C# unions and closed hierarchies model API values with a fixed set of possible types in ASP.NET Core. It contrasts unions with open inheritance-based polymorphism and describes System.Text.Json support. ### Source excerpt Learn how C# unions and closed hierarchies work with System.Text.Json across ASP.NET Core Minimal APIs, MVC, SignalR, Blazor, and OpenAPI. The post Use C# unions and closed hierarchies in ASP.NET Core appeared first on .NET Blog. ## Announcing .NET 11 Release Candidate 1 DevFeed: [Announcing .NET 11 Release Candidate 1]() Original publisher: [Read original article]() Author: .NET Team Published: 2026-09-08T21:30:00Z Content type: release Language: en Sources: [.NET Blog]() Topics: [.NET](), [WinForms]() Tags: [announcements](), [asp-net-core](), [c-sharp](), [f-sharp](), [featured](), [net](), [net-11](), [net-maui](), [nuget](), [production](), [release](), [release-notes](), [updates](), [visual-studio](), [visual-studio-2026](), [windows](), [winforms]() ### AI overview .NET 11 Release Candidate 1 is available with a go-live support license. It includes updates across the runtime, SDK, MSBuild, NuGet, C#, F#, ASP.NET Core, .NET MAUI, and Windows Forms. ### Source excerpt .NET 11 Release Candidate 1 is available with improvements across libraries, runtime, SDK, MSBuild, NuGet, C#, F#, ASP.NET Core, .NET MAUI, and Windows Forms. The post Announcing .NET 11 Release Candidate 1 appeared first on .NET Blog. ## .NET Conf 2026 Community Days Call for Presenters Is Open DevFeed: [.NET Conf 2026 Community Days Call for Presenters Is Open]() Original publisher: [Read original article]() Author: Javier Lozano, Chris Sfanos, Jon Galloway Published: 2026-09-08T20:30:00Z Content type: news Language: en Sources: [.NET Blog]() Topics: [.NET]() Tags: [call-for-presenters](), [community](), [conference](), [net](), [net-conf](), [virtual-event]() ### AI overview The .NET Conf 2026 Community Days call for presenters invites proposals for community-led sessions about building with .NET and software development practices. ### Source excerpt Submit your session proposal for the community-led .NET Conf 2026 Community Days by October 6, 2026. The post .NET Conf 2026 Community Days Call for Presenters Is Open appeared first on .NET Blog. ## .NET and .NET Framework September 2026 servicing releases updates DevFeed: [.NET and .NET Framework September 2026 servicing releases updates]() Original publisher: [Read original article]() Author: Rahul Bhandari (MSFT), Tara Overfield Published: 2026-09-08T20:00:00Z Content type: release Language: en Sources: [.NET Blog]() Topics: [.NET](), [releases]() Tags: [asp-net-core](), [maintenance-updates](), [net](), [net-framework](), [release-notes](), [releases](), [security](), [september-2026](), [updates]() ### AI overview September 2026 servicing releases for .NET and .NET Framework provide security and non-security fixes. The post lists updated ASP.NET Core, Entity Framework Core, and Runtime versions across .NET 10, 9, and 8 release lines. ### Source excerpt A recap of the latest servicing updates for .NET and .NET Framework for September 2026. The post .NET and .NET Framework September 2026 servicing releases updates appeared first on .NET Blog. ## Test what you ship: MSTest and Native AOT DevFeed: [Test what you ship: MSTest and Native AOT]() Original publisher: [Read original article]() Author: Amaury Levé Published: 2026-09-03T18:00:00Z Content type: article Language: en Sources: [.NET Blog]() Topics: [native aot](), [trimming](), [.NET](), [Code generation](), [Deployment]() Tags: [deployment](), [generation](), [mstest](), [native-aot](), [net](), [source-generators](), [testing](), [trimming]() ### AI overview MSTest 4.4 uses source generation to let test projects run as Native AOT executables, helping teams test under the same trimming and deployment constraints as their applications. The article explains that this can reveal application issues such as reflection-dependent serialization that managed test runs may miss. ### Source excerpt MSTest source generation lets test projects use the same Native AOT and trimming deployment model as the applications they validate, while reducing reflection on the test execution path. The post Test what you ship: MSTest and Native AOT appeared first on .NET Blog. ## How Uno Platform uses .NET, MCP, and AI to build high quality apps DevFeed: [How Uno Platform uses .NET, MCP, and AI to build high quality apps]() Original publisher: [Read original article]() Author: Sam Basu Published: 2026-08-27T17:00:00Z Content type: article Language: en Sources: [.NET Blog]() Topics: [.NET](), [AI-assisted coding]() Tags: [ai](), [ai-agents](), [api](), [browser](), [c-sharp](), [cross-platform](), [developer-stories](), [docs](), [documentation](), [github-copilot](), [http](), [mcp](), [model-context-protocol](), [net](), [server](), [servers](), [skiasharp](), [tooling](), [uno-platform](), [xaml]() ### AI overview Uno Platform describes using two C# Model Context Protocol servers to give AI agents current documentation and the ability to inspect and drive running cross-platform .NET apps. ### Source excerpt How Uno Platform built two Model Context Protocol servers in C# so AI agents can ground themselves in real documentation and then see and drive a running cross-platform .NET app. The post How Uno Platform uses .NET, MCP, and AI to build high quality apps appeared first on .NET Blog. ## .NET Conf 2026 - Save the Date DevFeed: [.NET Conf 2026 - Save the Date]() Original publisher: [Read original article]() Author: Jon Galloway Published: 2026-08-25T16:28:27Z Content type: news Language: en Sources: [.NET Blog]() Topics: [.NET Conf](), [.NET](), [C# 15](), [ASP.NET Core](), [Blazor](), [WebAssembly](), [Aspire](), [OpenAPI Specification](), [Model Context Protocol]() Tags: [asp-net-core](), [blazor](), [c-sharp-15](), [community](), [conference](), [event](), [mcp](), [net](), [net-11](), [net-conf](), [speakers](), [union-types](), [virtual-event](), [webassembly]() ### AI overview Microsoft announces .NET Conf 2026, a free online event running November 10-12, featuring community sessions and the launch of .NET 11. The article previews updates across .NET, including C# 15 union types, .NET MAUI, ASP.NET Core, Blazor, OpenAPI, Aspire, and the official MCP C# SDK. ### Source excerpt .NET Conf returns November 10-12, 2026, with three days of sessions, community, and the launch of .NET 11. The post .NET Conf 2026 - Save the Date appeared first on .NET Blog. ## From dotnet run to Foundry Hosted Agent in 3 lines of C# DevFeed: [From dotnet run to Foundry Hosted Agent in 3 lines of C#]() Original publisher: [Read original article]() Author: Bruno Capuano Published: 2026-08-24T19:00:00Z Content type: tutorial Language: en Sources: [.NET Blog]() Topics: [hosted-agents](), [Microsoft Agent Framework](), [Azure](), [C#](), [.NET](), [NuGet](), [Entra ID](), [Containers](), [telemetry]() Tags: [agent](), [agents](), [ai](), [azd](), [azure](), [blog](), [c-sharp](), [csharp](), [dotnet](), [entra-id](), [framework](), [hosted-agents](), [hosting](), [infrastructure](), [microsoft](), [microsoft-agent-framework](), [microsoft-foundry](), [net](), [nuget](), [observability](), [post](), [production]() ### AI overview This tutorial shows how to deploy a Microsoft Agent Framework console agent as a Foundry Hosted Agent using one NuGet package, three lines of C#, and two commands. Foundry provides managed Azure infrastructure, scaling, identity, session state, observability, and lifecycle management. ### Source excerpt You built an agent with Microsoft Agent Framework and it works great on your machine. Now what? Turns out deploying it to production takes 1 NuGet package, 3 lines of C#, and 2 commands. Let's do it. The post From dotnet run to Foundry Hosted Agent in 3 lines of C# appeared first on .NET Blog. ## Explore new features available in C# 15 preview DevFeed: [Explore new features available in C# 15 preview]() Original publisher: [Read original article]() Author: Bill Wagner Published: 2026-08-24T17:00:00Z Content type: article Language: en Sources: [.NET Blog]() Topics: [C# 15](), [.NET](), [union types](), [.NET 11 Preview 7]() Tags: [blog](), [c-sharp](), [c-sharp-15](), [closed-hierarchies](), [dotnet](), [features](), [net](), [net-11](), [net-11-preview-7](), [union-types]() ### AI overview An overview of the new features in C# 15, which ships with .NET 11. The article covers union types, closed hierarchies, the preview memory-safety redesign, and several smaller language changes. ### Source excerpt C# 15 ships with .NET 11. It adds union types, closed hierarchies, a preview of the updated unsafe model, and a few smaller changes that remove everyday ceremony. The post Explore new features available in C# 15 preview appeared first on .NET Blog. ## Routing and Failover for Microsoft.Extensions.AI DevFeed: [Routing and Failover for Microsoft.Extensions.AI]() Original publisher: [Read original article]() Author: Joshua Yue Published: 2026-08-13T19:30:00Z Content type: article Language: en Sources: [.NET Blog]() Topics: [AI Chat](), [.NET]() Tags: [ai](), [ai-routing](), [c-sharp](), [cache](), [embeddings](), [generative-ai](), [latency](), [llm](), [microsoft-extensions-ai](), [models](), [net](), [routing]() ### AI overview Microsoft.Extensions.AI introduces experimental routing and failover primitives for directing chat requests across models and providers. The article covers custom routing policies, semantic routing using embeddings, option handling across attempts, and constraints when switching providers during reasoning conversations. ### Source excerpt Route requests across models and providers natively in Microsoft.Extensions.AI with RoutingChatClient, SemanticRoutingChatClient, and FailoverChatClient -- new experimental primitives for content-based routing, failover, and custom routing policies. The post Routing and Failover for Microsoft.Extensions.AI appeared first on .NET Blog.