Manages NuGet packages in old-style .NET Framework projects (.NET Framework 4.x). Handles both packages.config (classic NuGet) and PackageReference in non-SDK-style csproj files. Use when updating, adding, or removing NuGet packages in projects that use packages.config, have old-style csproj format (ToolsVersion attribute), or target .NET Framework without SDK-style project format.
Install
npx skills add microsoft/upgrade-agent-plugins --skill managing-legacy-dotnet-packagesnpx skills add microsoft/upgrade-agent-plugins --skill managing-legacy-dotnet-packages -a claude-code -gnpx skills add microsoft/upgrade-agent-plugins --skill managing-legacy-dotnet-packages -a codex -ggemini skills install https://github.com/microsoft/upgrade-agent-plugins.git --path plugins/upgrade-agent/upgrade/dotnet/skills/lazy/common/managing-legacy-dotnet-packagesgh skill install microsoft/upgrade-agent-plugins managing-legacy-dotnet-packagesgit clone --depth 1 https://github.com/microsoft/upgrade-agent-plugins /tmp/microsoft__upgrade-agent-plugins
mkdir -p ~/.claude/skills ~/.agents/skills
cp -R /tmp/microsoft__upgrade-agent-plugins/plugins/upgrade-agent/upgrade/dotnet/skills/lazy/common/managing-legacy-dotnet-packages ~/.claude/skills/managing-legacy-dotnet-packages # Claude Code
cp -R /tmp/microsoft__upgrade-agent-plugins/plugins/upgrade-agent/upgrade/dotnet/skills/lazy/common/managing-legacy-dotnet-packages ~/.agents/skills/managing-legacy-dotnet-packages # Codex, Cursor, Gemini CLI, Copilot, OpenCode