Migrates ASP.NET Framework validation to ASP.NET Core including data annotations, custom ValidationAttribute classes, ModelState handling, client-side unobtrusive validation, and FluentValidation integration.
Install
npx skills add microsoft/upgrade-agent-plugins --skill migrating-mvc-validationnpx skills add microsoft/upgrade-agent-plugins --skill migrating-mvc-validation -a claude-code -gnpx skills add microsoft/upgrade-agent-plugins --skill migrating-mvc-validation -a codex -ggemini skills install https://github.com/microsoft/upgrade-agent-plugins.git --path plugins/upgrade-agent/upgrade/dotnet/skills/lazy/web/mvc/migrating-mvc-validationgh skill install microsoft/upgrade-agent-plugins migrating-mvc-validationgit 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/web/mvc/migrating-mvc-validation ~/.claude/skills/migrating-mvc-validation # Claude Code
cp -R /tmp/microsoft__upgrade-agent-plugins/plugins/upgrade-agent/upgrade/dotnet/skills/lazy/web/mvc/migrating-mvc-validation ~/.agents/skills/migrating-mvc-validation # Codex, Cursor, Gemini CLI, Copilot, OpenCode