Add Identity metrics documentation for .NET 10 (#36324)

* Initial plan

* Add Identity metrics documentation for .NET 10

Co-authored-by: wadepickett <10985336+wadepickett@users.noreply.github.com>

* Update ASP.NET Core Identity documentation

Fixed for moniker range.

* Apply suggestion from @wadepickett

Added to View Identity metric section

* Apply suggestions from code review

Suggested udpated from guardrex

Co-authored-by: Luke Latham <1622880+guardrex@users.noreply.github.com>

* Apply suggestion from @wadepickett

Fixed comma

* Fix punctuation and formatting in metrics.md

Corrected punctuation and formatting for consistency in metrics documentation.

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: wadepickett <10985336+wadepickett@users.noreply.github.com>
Co-authored-by: Wade Pickett <wpickett@microsoft.com>
Co-authored-by: Luke Latham <1622880+guardrex@users.noreply.github.com>

Author: 3 people

aspnetcore/log-mon/metrics/metrics.md

@@ -1,10 +1,11 @@
 ---
 title: ASP.NET Core metrics
-description: Metrics for ASP.NET Core apps
+ai-usage: ai-assisted
 author: tdykstra
-ms.author: tdykstra
+description: Metrics for ASP.NET Core apps
 monikerRange: '>= aspnetcore-8.0'
-ms.date: 10/18/2023
+ms.author: tdykstra
+ms.date: 11/10/2025
 ms.topic: article
 uid: log-mon/metrics/metrics
 ---
@@ -256,12 +257,57 @@ The proceeding test:
 
 * Bootstraps a web app in memory with <xref:Microsoft.AspNetCore.Mvc.Testing.WebApplicationFactory%601>. `Program` in the factory's generic argument specifies the web app.
 * Collects metrics values with <xref:Microsoft.Extensions.Diagnostics.Metrics.Testing.MetricCollector%601>
-  * Requires a package reference to `Microsoft.Extensions.Diagnostics.Testing`
+  * Requires a package reference to `Microsoft.Extensions.Diagnostics.Testing`.
   * The `MetricCollector<T>` is created using the web app's <xref:System.Diagnostics.Metrics.IMeterFactory>. This allows the collector to only report metrics values recorded by test.
   * Includes the meter name, `Microsoft.AspNetCore.Hosting`, and counter name, `http.server.request.duration` to collect.
 * Makes an HTTP request to the web app.
 * Asserts the test using results from the metrics collector.
 
+:::moniker range=">= aspnetcore-10.0"
+
+## ASP.NET Core Identity metrics
+
+ASP.NET Core Identity observability help you monitor user management activities and authentication processes.
+
+The metrics are in the `Microsoft.AspNetCore.Identity` meter and are described in the following sections.
+
+### User management metrics
+
+* `aspnetcore.identity.user.create.duration` measures the duration of user creation operations.
+* `aspnetcore.identity.user.update.duration` measures the duration of user update operations.
+* `aspnetcore.identity.user.delete.duration` measures the duration of user deletion operations
+* `aspnetcore.identity.user.check_password_attempts` counts password verification attempts.
+* `aspnetcore.identity.user.generated_tokens` counts tokens generated for users, such as password reset tokens.
+* `aspnetcore.identity.user.verify_token_attempts` counts token verification attempts.
+
+### Authentication metrics
+
+* `aspnetcore.identity.sign_in.authenticate.duration` measures the duration of authentication operations.
+* `aspnetcore.identity.sign_in.check_password_attempts` counts password check attempts during sign-in.
+* `aspnetcore.identity.sign_in.sign_ins` counts successful sign-ins.
+* `aspnetcore.identity.sign_in.sign_outs` counts sign-outs.
+* `aspnetcore.identity.sign_in.two_factor_clients_remembered` counts remembered two-factor clients.
+* `aspnetcore.identity.sign_in.two_factor_clients_forgotten` counts forgotten two-factor clients.
+
+These metrics can be used to:
+
+* Monitor user registration and management.
+* Track authentication patterns and potential security issues.
+* Measure performance of Identity operations.
+* Observe two-factor authentication usage.
+
+### Viewing Identity metrics
+
+You can view these metrics using `dotnet-counters` to monitor them in real-time or export them to Prometheus and visualize them in Grafana using the techniques described earlier in this article.
+
+For example, to monitor all Identity metrics with `dotnet-counters`:
+
+```dotnetcli
+dotnet-counters monitor -n YourAppName --counters Microsoft.AspNetCore.Identity
+```
+
+:::moniker-end
+
 ## ASP.NET Core meters and counters
 
 See [ASP.NET Core metrics](/dotnet/core/diagnostics/built-in-metrics-aspnetcore) for a list of ASP.NET Core meters and counters.

aspnetcore/security/authentication/identity.md

@@ -1,10 +1,11 @@
 ---
 title: Introduction to Identity on ASP.NET Core
+ai-usage: ai-assisted
 author: wadepickett
 description: Use Identity with an ASP.NET Core app. Learn how to set password requirements (RequireDigit, RequiredLength, RequiredUniqueChars, and more).
 monikerRange: '>= aspnetcore-3.0'
 ms.author: wpickett
-ms.date: 10/30/2025
+ms.date: 11/10/2025
 uid: security/authentication/identity
 ---
 # Introduction to Identity on ASP.NET Core
@@ -202,6 +203,20 @@ The template-generated app doesn't use [authorization](xref:security/authorizati
 
 For more information on `IdentityOptions`, see <xref:Microsoft.AspNetCore.Identity.IdentityOptions> and [Application Startup](xref:fundamentals/startup).
 
+:::moniker-end
+
+:::moniker range=">= aspnetcore-10.0"
+
+## ASP.NET Core Identity metrics
+
+ASP.NET Core Identity metrics provide monitoring capabilities for user management and authentication processes. These metrics help you detect unusual sign-in patterns that might indicate security threats, track the performance of identity operations, and understand how users interact with authentication features, such as two-factor authentication. This observability is particularly valuable for apps with strict security requirements or those experiencing high authentication traffic.
+
+For complete details on available metrics and how to use them, see <xref:log-mon/metrics/metrics#aspnet-core-identity-metrics>.
+
+:::moniker-end
+
+:::moniker range=">= aspnetcore-8.0"
+
 <!-- Start here for .NET 6 -->
 
 ## Scaffold Register, Login, LogOut, and RegisterConfirmation