Migrates legacy ASP.NET Web API CORS (Microsoft.AspNet.WebApi.Cors) to ASP.NET Core CORS (Microsoft.AspNetCore.Cors). Use ONLY when Microsoft.AspNet.WebApi.Cors has been flagged as obsolete or deprecated and must be replaced — not for version-bump scenarios where Microsoft.AspNet.WebApi.Cors is still supported.
Install
npx skills add microsoft/upgrade-agent-plugins --skill migrating-webapi-corsnpx skills add microsoft/upgrade-agent-plugins --skill migrating-webapi-cors -a claude-code -gnpx skills add microsoft/upgrade-agent-plugins --skill migrating-webapi-cors -a codex -ggemini skills install https://github.com/microsoft/upgrade-agent-plugins.git --path plugins/upgrade-agent/upgrade/dotnet/skills/lazy/libraries/migrating-webapi-corsgh skill install microsoft/upgrade-agent-plugins migrating-webapi-corsgit 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/libraries/migrating-webapi-cors ~/.claude/skills/migrating-webapi-cors # Claude Code
cp -R /tmp/microsoft__upgrade-agent-plugins/plugins/upgrade-agent/upgrade/dotnet/skills/lazy/libraries/migrating-webapi-cors ~/.agents/skills/migrating-webapi-cors # Codex, Cursor, Gemini CLI, Copilot, OpenCode