semantic-kernel

Semantic Kernel .NET 1.81.0 fixes a FileIOPlugin oracle: WriteAsync told the model a file outside AllowedFolders existed, was read-only, and where it lived. Measured before and after.

Semantic Kernel .NET 1.80.0 ships a breaking change: the OpenAPI plugin's default HttpClient no longer follows redirects, closing an SSRF bypass. Here is what changes and why your own HttpClient reopens the hole.

A step-by-step checklist for moving an existing Semantic Kernel 1.77 .NET app to Microsoft Agent Framework 1.13. Covers the Kernel-to-AIAgent rewrite, plugins-to-tools, thread-to-session, the KernelFunction compatibility bridge, DI changes, and the gotchas that bite mid-cutover.

For a new .NET agent in 2026, start on Microsoft Agent Framework 1.0. Semantic Kernel is in maintenance mode. Here is the side-by-side and the one case where SK still wins.

Wire a Microsoft.SemanticKernel 1.75.0 plugin into a hosted BackgroundService on .NET 11 and invoke its KernelFunctions on a PeriodicTimer schedule. Covers DI scopes, [KernelFunction] resolution, prompt-cache-friendly invocation, cancellation, and the lifetime gotchas that bite when you move a plugin off the request path.

Take an existing Semantic Kernel plugin with [KernelFunction] methods and turn it into a Model Context Protocol server other agents can call. Covers the drop-in WithTools(kernel) bridge, the native [McpServerTool] rewrite, parameter binding, dependency injection, and the gotchas that bite during the cutover.