Microsoft's official collection of AI coding agent skills for .NET, injecting domain expertise and workflow automation into tools like Copilot CLI, Claude Code, and Cursor.
.NET Agent Skills is an open-source project maintained by Microsoft's dotnet organization on GitHub. Following the agentskills.io open standard, it provides .NET domain expertise to AI coding agents in the form of Markdown instructions with optional scripts. Skills are organized into 12 plugins covering core .NET development, data access (Entity Framework), performance diagnostics, MSBuild troubleshooting, NuGet package management, framework upgrade migration, MAUI mobile, AI/ML integration (LLM, RAG, MCP, ML.NET), template engine, testing, ASP.NET Core, and experimental skills. Each plugin can also define role-based Agents (e.g., "WinForms Expert", "Security Reviewer") with explicit role boundaries and skill selection strategies.
Skills use a progressive disclosure loading mechanism—only names and descriptions are loaded at startup, with full instructions loaded upon matching—effectively controlling context window usage. Some plugins provide GitHub Agentic Workflow templates that can be compiled into .lock.yml via the gh aw CLI for CI/CD automation. The project includes a C#-based skill-validator framework supporting eval.yaml-defined test scenarios (prompt → assertion → rubric) for both local and CI-level skill quality evaluation. For security, CI pipelines automatically scan for external link safety, pipe-to-shell risks, etc., and a CODEOWNERS mechanism ensures code ownership for every skill module.
The project is compatible with major AI coding clients including Copilot CLI, Claude Code, VS Code Copilot Chat, Cursor, and OpenAI Codex CLI, accessible through a unified marketplace source mechanism or local symlink. Primary languages are C# (97.2%) and PowerShell (2.1%), licensed under MIT, with v1.0.0 released.