.NET Agent Skills

dotnet/skills is the official .NET team marketplace for Agent Skills and custom agents. It gives Claude Code, Codex, GitHub Copilot, Cursor, and other skill-aware coding agents source-backed guidance for .NET, C#, ASP.NET Core, Blazor, MAUI, Entity Framework, diagnostics, MSBuild, NuGet, tests, upgrades, AI workflows, RAG pipelines, and C# MCP servers.

This is especially useful for teams that want AI coding agents to follow modern .NET conventions instead of generic C# advice. The repository ships a Codex-native marketplace manifest, plugin manifests, individual SKILL.md files, and a dashboard for accuracy and efficiency scoring trends.

Knowledge Freshness

The repository is maintained by the .NET team at Microsoft and currently includes plugins for core .NET work, data access, diagnostics, MSBuild, NuGet, upgrades, MAUI, AI, template authoring, tests, ASP.NET Core, Blazor, and .NET 11 APIs. .NET SDKs, templates, NuGet packages, ASP.NET Core APIs, MCP SDK patterns, and preview framework guidance change quickly.

Use the skills for workflow structure and agent guardrails, then verify exact commands, package versions, target frameworks, and deployment constraints against the application's repository and the currently installed .NET SDK.

Retrieval Sources

This listing is grounded in:

• The dotnet/skills repository README.
• The .agents/plugins/marketplace.json marketplace manifest.
• The dotnet-ai plugin manifest.
• Representative SKILL.md files for C# MCP server creation and testing.
• Representative ASP.NET Core Web API and diagnostics skills.
• The repository license and official GitHub organization metadata.

Core Workflow

Install the marketplace for Codex:

codex plugin marketplace add dotnet/skills

Open Codex and install from the plugin browser:

/plugins

For Claude Code or Copilot CLI:

/plugin marketplace add dotnet/skills
/plugin install dotnet-ai@dotnet-agent-skills

Install an individual skill directly when you only want one workflow:

skill-installer install https://github.com/dotnet/skills/tree/main/plugins/dotnet-ai/skills/mcp-csharp-create

Capability Scope

The marketplace currently exposes these plugin groups:

For MCP-specific traffic, the dotnet-ai plugin is the highest-value starting point. It includes C# MCP server workflows for creating servers with the official SDK and templates, choosing stdio or HTTP transports, implementing tools, adding prompts and resources, debugging servers, testing with MCP client integration tests, and preparing publish workflows.

Production Rules

Use these skills as expert workflow guidance, but keep repository and runtime boundaries explicit:

• Inspect the target solution, SDK version, target frameworks, package graph, tests, and deployment path before broad changes.
• Keep generated code, package upgrades, lock files, and project file edits separately reviewable.
• Run dotnet build, targeted tests, and the repository's existing validation before proposing production changes.
• For ASP.NET Core work, preserve existing controller or minimal API style rather than mixing patterns.
• For MCP servers, document every tool, validate parameters, restrict network and filesystem access, and choose stdio or HTTP transport based on the intended trust boundary.
• For diagnostics, avoid collecting dumps, traces, counters, or binlogs unless the user approves the environment, retention plan, and redaction path.
• For NuGet publish tasks, verify package identity, feed target, API key scope, signing policy, and rollback path before pushing artifacts.

Use Cases

• Ask Codex to scaffold a C# MCP server with the official SDK and stdio transport.
• Have Claude Code add MCP tool tests using the C# MCP client SDK.
• Use Copilot to diagnose an ASP.NET Core Web API endpoint and produce OpenAPI metadata that matches the existing API style.
• Ask Cursor to review a hot path for .NET performance anti-patterns.
• Use an agent to triage MSBuild failures, NuGet dependency drift, or .NET upgrade blockers with source-specific workflows instead of generic guesses.

Source Review

• The README describes .NET Agent Skills as the .NET team's curated set of core skills and custom agents for coding agents.
• The repository includes a dashboard for accuracy and efficiency scoring trends across contained plugins.
• The Codex installation section says the repository ships a Codex-native marketplace manifest at .agents/plugins/marketplace.json.
• The marketplace manifest names .NET Team at Microsoft as the owner and lists plugin groups for core .NET, data, diagnostics, MSBuild, NuGet, upgrades, MAUI, AI, template engine, tests, ASP.NET Core, Blazor, and .NET 11 work.
• The mcp-csharp-create skill covers dotnet new mcpserver, the official C# MCP SDK, tool/prompt/resource implementation, and stdio versus HTTP transport choices.
• The mcp-csharp-test skill covers unit tests, MCP protocol integration tests, HTTP MCP testing, and evaluations for server quality.
• The license file identifies the repository as MIT licensed.

Duplicate Review

Checked current content/skills/, content/tools/, content/mcp/, open pull requests, and repository-wide content for .NET Agent Skills, dotnet/skills, dotnet-agent-skills, mcp-csharp-create, dotnet-ai, and C# MCP skill phrases. Existing .NET content is older rules or agent guidance, not this official Microsoft skill marketplace, and no exact source URL duplicate or open duplicate PR was found.

Disclosure

Editorial listing. No paid placement or affiliate link is used. The upstream repository is maintained under the official dotnet GitHub organization and is MIT licensed.