Manages authentication in Blazor Server applications with ASP.NET Core Identity. Solves critical Blazor Server auth issues: HttpContext NULL errors during WebSocket circuits, cookie auth operations failing silently in component handlers, login/logout not working in interactive mode, SignInManager returning null, cascading auth state parameter errors.
Install
npx skills add microsoft/upgrade-agent-plugins --skill managing-blazor-server-authenticationnpx skills add microsoft/upgrade-agent-plugins --skill managing-blazor-server-authentication -a claude-code -gnpx skills add microsoft/upgrade-agent-plugins --skill managing-blazor-server-authentication -a codex -ggemini skills install https://github.com/microsoft/upgrade-agent-plugins.git --path plugins/upgrade-agent/upgrade/dotnet/skills/lazy/web/webforms/managing-blazor-server-authenticationgh skill install microsoft/upgrade-agent-plugins managing-blazor-server-authenticationgit 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/webforms/managing-blazor-server-authentication ~/.claude/skills/managing-blazor-server-authentication # Claude Code
cp -R /tmp/microsoft__upgrade-agent-plugins/plugins/upgrade-agent/upgrade/dotnet/skills/lazy/web/webforms/managing-blazor-server-authentication ~/.agents/skills/managing-blazor-server-authentication # Codex, Cursor, Gemini CLI, Copilot, OpenCode