Migrates legacy OWIN cookie authentication (Microsoft.Owin.Security.Cookies) to ASP.NET Core cookie authentication (Microsoft.AspNetCore.Authentication.Cookies). Use ONLY when Microsoft.Owin.Security.Cookies has been flagged as obsolete or deprecated and must be replaced — not for version-bump scenarios where the OWIN package is still supported.
Install
npx skills add microsoft/upgrade-agent-plugins --skill migrating-owin-cookie-authnpx skills add microsoft/upgrade-agent-plugins --skill migrating-owin-cookie-auth -a claude-code -gnpx skills add microsoft/upgrade-agent-plugins --skill migrating-owin-cookie-auth -a codex -ggemini skills install https://github.com/microsoft/upgrade-agent-plugins.git --path plugins/upgrade-agent/upgrade/dotnet/skills/lazy/libraries/migrating-owin-cookie-authgh skill install microsoft/upgrade-agent-plugins migrating-owin-cookie-authgit 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-owin-cookie-auth ~/.claude/skills/migrating-owin-cookie-auth # Claude Code
cp -R /tmp/microsoft__upgrade-agent-plugins/plugins/upgrade-agent/upgrade/dotnet/skills/lazy/libraries/migrating-owin-cookie-auth ~/.agents/skills/migrating-owin-cookie-auth # Codex, Cursor, Gemini CLI, Copilot, OpenCode