sentry-dotnet-sdk

by sentry

Full Sentry SDK setup for .NET. Use when asked to "add Sentry to .NET", "install Sentry for C#", or configure error monitoring, tracing, profiling, logging, or… npx skills add https://github.com/getsentry/sentry-for-claude --skill sentry-dotnet-sdk Download ZIPGitHub232

All Skills > SDK Setup > .NET SDK

Sentry .NET SDK

Opinionated wizard that scans your .NET project and guides you through complete Sentry setup: error monitoring, distributed tracing, profiling, structured logging, and cron monitoring across all major .NET frameworks.

Invoke This Skill When

• User asks to "add Sentry to .NET", "set up Sentry in C#", or "install Sentry for ASP.NET Core"

• User wants error monitoring, tracing, profiling, logging, or crons for a .NET app

• User mentions SentrySdk.Init, UseSentry, Sentry.AspNetCore, or Sentry.Maui

• User wants to capture unhandled exceptions in WPF, WinForms, MAUI, or Azure Functions

• User asks about SentryOptions, BeforeSend, TracesSampleRate, or symbol upload

Note: SDK version and APIs below reflect Sentry NuGet packages ≥6.1.0 (OTLP export requires ≥6.5.0). Always verify against docs.sentry.io/platforms/dotnet/ before implementing.

Phase 1: Detect

Run these commands to understand the project before making any recommendations:

# Detect framework type — find all .csproj files
find . -name "*.csproj" | head -20

# Detect framework targets
grep -r "TargetFramework\|Project Sdk" --include="*.csproj" .

# Check for existing Sentry packages
grep -r "Sentry" --include="*.csproj" . | grep "PackageReference"

# Check startup files
ls Program.cs src/Program.cs App.xaml.cs MauiProgram.cs 2>/dev/null

# Check for appsettings
ls appsettings.json src/appsettings.json 2>/dev/null

# Check for logging libraries
grep -r "Serilog\|NLog\|log4net" --include="*.csproj" .

# Check for companion frontend
ls ../frontend ../client ../web 2>/dev/null
cat ../package.json 2>/dev/null | grep -E '"next"|"react"|"vue"' | head -3

What to determine:

Question Impact Framework type? Determines correct package and init pattern .NET version? .NET 8+ recommended; .NET Framework 4.6.2+ supported Sentry already installed? Skip install, go to feature config Logging library (Serilog, NLog)? Recommend matching Sentry sink/target Async/hosted app (ASP.NET Core)? UseSentry() on WebHost; no IsGlobalModeEnabled needed Desktop app (WPF, WinForms, WinUI)? Must set IsGlobalModeEnabled = true Serverless (Azure Functions, Lambda)? Must set FlushOnCompletedRequest = true Frontend directory found? Trigger Phase 4 cross-link

Framework → Package mapping:

Detected Package to install Sdk="Microsoft.NET.Sdk.Web" (ASP.NET Core) Sentry.AspNetCore App.xaml.cs with Application base Sentry (WPF) [STAThread] in Program.cs Sentry (WinForms) MauiProgram.cs Sentry.Maui WebAssemblyHostBuilder Sentry.AspNetCore.Blazor.WebAssembly FunctionsStartup Sentry.Extensions.Logging + Sentry.OpenTelemetry HttpApplication / Global.asax Sentry.AspNet Generic host / Worker Service Sentry.Extensions.Logging

Phase 2: Recommend

Present a concrete recommendation based on what you found. Lead with a proposal — don't ask open-ended questions.

Recommended (core coverage):

• ✅ Error Monitoring — always; captures unhandled exceptions, structured captures, scope enrichment

• ✅ Tracing — always for ASP.NET Core and hosted apps; auto-instruments HTTP requests and EF Core queries

• ✅ Logging — recommended for all apps; routes ILogger / Serilog / NLog entries to Sentry as breadcrumbs and events

Optional (enhanced observability):

• ⚡ Profiling — CPU profiling; recommend for performance-critical services running on .NET 6+

• ⚡ Metrics — counters, gauges, distributions linked to traces; recommend for apps that need custom business metrics

• ⚡ Crons — detect missed/failed scheduled jobs; recommend when Hangfire, Quartz.NET, or scheduled endpoints detected

Recommendation logic:

Feature Recommend when... Error Monitoring Always — non-negotiable baseline Tracing Always for ASP.NET Core — request traces, EF Core spans, HttpClient spans are high-value Logging App uses ILogger<T>, Serilog, NLog, or log4net Profiling Performance-critical service on .NET 6+ Metrics App needs custom business metrics (request counts, queue depths, response times) Crons App uses Hangfire, Quartz.NET, or scheduled Azure Functions

Propose: "I recommend setting up Error Monitoring + Tracing + Logging. Want me to also add Profiling or Crons?"

Phase 3: Guide

Option 1: Wizard (Recommended)

You need to run this yourself — the wizard opens a browser for login and requires interactive input that the agent can't handle. Copy-paste into your terminal:

npx @sentry/wizard@latest -i dotnet

It handles login, org/project selection, DSN configuration, and MSBuild symbol upload setup for readable stack traces in production.

Once it finishes, come back and skip to Verification .

If the user skips the wizard, proceed with Option 2 (Manual Setup) below.

Option 2: Manual Setup

Install the right package

# ASP.NET Core
dotnet add package Sentry.AspNetCore -v 6.1.0

# WPF or WinForms or Console
dotnet add package Sentry -v 6.1.0

# .NET MAUI
dotnet add package Sentry.Maui -v 6.1.0

# Blazor WebAssembly
dotnet add package Sentry.AspNetCore.Blazor.WebAssembly -v 6.1.0

# Azure Functions (Isolated Worker)
dotnet add package Sentry.Extensions.Logging -v 6.1.0
dotnet add package Sentry.OpenTelemetry -v 6.1.0

# Classic ASP.NET (System.Web / .NET Framework)
dotnet add package Sentry.AspNet -v 6.1.0

ASP.NET Core — Program.cs

var builder = WebApplication.CreateBuilder(args);

builder.WebHost.UseSentry(options =>
{
 options.Dsn = Environment.GetEnvironmentVariable("SENTRY_DSN")
 ?? "___YOUR_DSN___";
 options.Debug = true; // disable in production
 options.SendDefaultPii = true; // captures user IP, name, email
 options.MaxRequestBodySize = RequestSize.Always;
 options.MinimumBreadcrumbLevel = LogLevel.Debug;
 options.MinimumEventLevel = LogLevel.Warning;
 options.TracesSampleRate = 1.0; // tune to 0.1–0.2 in production
 options.SetBeforeSend((@event, hint) =>
 {
 @event.ServerName = null; // scrub hostname from events
 return @event;
 });
});

var app = builder.Build();
app.Run();

appsettings.json (alternative configuration):

{
 "Sentry": {
 "Dsn": "___YOUR_DSN___",
 "SendDefaultPii": true,
 "MaxRequestBodySize": "Always",
 "MinimumBreadcrumbLevel": "Debug",
 "MinimumEventLevel": "Warning",
 "AttachStacktrace": true,
 "Debug": true,
 "TracesSampleRate": 1.0,
 "Environment": "production",
 "Release": "[email protected]"
 }
}

Environment variables (double underscore as separator):

export Sentry__Dsn="https://[email protected]/0"
export Sentry__TracesSampleRate="0.1"
export Sentry__Environment="staging"

WPF — App.xaml.cs

⚠️ Critical: Initialize in the constructor, NOT in OnStartup(). The constructor fires earlier, catching more failure modes.

using System.Windows;
using Sentry;

public partial class App : Application
{
 public App()
 {
 SentrySdk.Init(options =>
 {
 options.Dsn = "___YOUR_DSN___";
 options.Debug = true;
 options.SendDefaultPii = true;
 options.TracesSampleRate = 1.0;
 options.IsGlobalModeEnabled = true; // required for all desktop apps
 });

 // Capture WPF UI-thread exceptions before WPF's crash dialog appears
 DispatcherUnhandledException += App_DispatcherUnhandledException;
 }

 private void App_DispatcherUnhandledException(
 object sender,
 System.Windows.Threading.DispatcherUnhandledExceptionEventArgs e)
 {
 SentrySdk.CaptureException(e.Exception);
 // Set e.Handled = true to prevent crash dialog and keep app running
 }
}

WinForms — Program.cs

using System;
using System.Windows.Forms;
using Sentry;

static class Program
{
 [STAThread]
 static void Main()
 {
 Application.EnableVisualStyles();
 Application.SetCompatibleTextRenderingDefault(false);

 // Required: allows Sentry to see unhandled WinForms exceptions
 Application.SetUnhandledExceptionMode(UnhandledExceptionMode.ThrowException);

 using (SentrySdk.Init(new SentryOptions
 {
 Dsn = "___YOUR_DSN___",
 Debug = true,
 TracesSampleRate = 1.0,
 IsGlobalModeEnabled = true, // required for desktop apps
 }))
 {
 Application.Run(new MainForm());
 } // Disposing flushes all pending events
 }
}

.NET MAUI — MauiProgram.cs

public static class MauiProgram
{
 public static MauiApp CreateMauiApp()
 {
 var builder = MauiApp.CreateBuilder();
 builder
 .UseMauiApp ()
 .UseSentry(options =>
 {
 options.Dsn = "___YOUR_DSN___";
 options.Debug = true;
 options.SendDefaultPii = true;
 options.TracesSampleRate = 1.0;
 // MAUI-specific: opt-in breadcrumbs (off by default — PII risk)
 options.IncludeTextInBreadcrumbs = false;
 options.IncludeTitleInBreadcrumbs = false;
 options.IncludeBackgroundingStateInBreadcrumbs = false;
 });

 return builder.Build();
 }
}

Blazor WebAssembly — Program.cs

var builder = WebAssemblyHostBuilder.CreateDefault(args);

builder.UseSentry(options =>
{
 options.Dsn = "___YOUR_DSN___";
 options.Debug = true;
 options.SendDefaultPii = true;
 options.TracesSampleRate = 0.1;
});

// Hook logging pipeline without re-initializing the SDK
builder.Logging.AddSentry(o => o.InitializeSdk = false);

await builder.Build().RunAsync();

Azure Functions (Isolated Worker) — Program.cs

Recommended: Install Sentry.OpenTelemetry.Exporter (≥6.5.0) for OTLP export. Alternatively, use Sentry.OpenTelemetry for the bridge pattern.

using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using OpenTelemetry.Trace;

// Package: Sentry.OpenTelemetry.Exporter
var host = new HostBuilder()
 .ConfigureFunctionsWorkerDefaults()
 .ConfigureLogging(logging =>
 {
 logging.AddSentry(options =>
 {
 options.Dsn = "___YOUR_DSN___";
 options.Debug = true;
 options.TracesSampleRate = 1.0;
 options.UseOtlp(); // send OTel spans via OTLP (requires 6.5.0+)
 });
 })
 .ConfigureServices(services =>
 {
 services.AddOpenTelemetry().WithTracing(builder =>
 {
 builder
 .AddHttpClientInstrumentation()
 .AddSentryOtlpExporter("___YOUR_DSN___"); // route spans to Sentry OTLP endpoint
 });
 })
 .Build();

await host.RunAsync();

AWS Lambda — LambdaEntryPoint.cs

public class LambdaEntryPoint : APIGatewayProxyFunction
{
 protected override void Init(IWebHostBuilder builder)
 {
 builder
 .UseSentry(options =>
 {
 options.Dsn = "___YOUR_DSN___";
 options.TracesSampleRate = 1.0;
 options.FlushOnCompletedRequest = true; // REQUIRED for Lambda
 })
 .UseStartup ();
 }
}

Classic ASP.NET — Global.asax.cs

public class MvcApplication : HttpApplication
{
 private IDisposable _sentry;

 protected void Application_Start()
 {
 _sentry = SentrySdk.Init(options =>
 {
 options.Dsn = "___YOUR_DSN___";
 options.TracesSampleRate = 1.0;
 options.AddEntityFramework(); // EF6 query breadcrumbs
 options.AddAspNet(); // Classic ASP.NET integration
 });
 }

 protected void Application_Error() => Server.CaptureLastError();

 protected void Application_BeginRequest() => Context.StartSentryTransaction();
 protected void Application_EndRequest() => Context.FinishSentryTransaction();

 protected void Application_End() => _sentry?.Dispose();
}

Symbol Upload (Readable Stack Traces)

Without debug symbols, stack traces show only method names — no file names or line numbers. The SDK uploads PDB files (and optionally sources) via MSBuild properties on Release builds:

 
 ___ORG_SLUG___ 
 ___PROJECT_SLUG___ 
 true 
 true 
 true 
 true 
 

Upload needs a SENTRY_AUTH_TOKEN set in CI (a secret). For creating the token and the CI wiring, see sentry-source-maps. The SentryCreateRelease / SentrySetCommits properties also create a release with suspect commits — see sentry-releases.

For Each Agreed Feature

Load the corresponding reference file and follow its steps:

Feature Reference file Load when... Error Monitoring references/error-monitoring.md Always — CaptureException, scopes, enrichment, filtering Tracing references/tracing.md Server apps, distributed tracing, EF Core spans, custom instrumentation Profiling references/profiling.md Performance-critical apps on .NET 6+ Logging references/logging.md ILogger<T>, Serilog, NLog, log4net integration Metrics references/metrics.md Custom counters, gauges, distributions; EmitCounter, EmitGauge, EmitDistribution Crons references/crons.md Hangfire, Quartz.NET, or scheduled function monitoring

For each feature: read the reference file, follow its steps exactly, and verify before moving on.

Verification

After wizard or manual setup, add a test throw and remove it after verifying:

// ASP.NET Core: add a temporary endpoint
app.MapGet("/sentry-test", () =>
{
 throw new Exception("Sentry test error — delete me");
});

// Or capture explicitly anywhere
SentrySdk.CaptureException(new Exception("Sentry test error — delete me"));

Then check your Sentry Issues dashboard — the error should appear within ~30 seconds.

Verification checklist:

Check How Exceptions captured Throw a test exception, verify in Sentry Issues Stack traces readable Check that file names and line numbers appear Tracing active Check Performance tab for transactions Logging wired Log an error via ILogger, check it appears as Sentry breadcrumb Symbol upload working Stack trace shows Controllers/HomeController.cs:42 not <unknown>

Phase 4: Cross-Link

After completing .NET setup, check for companion frontend projects:

# Check for frontend in adjacent directories
ls ../frontend ../client ../web ../app 2>/dev/null

# Check for JavaScript framework indicators
cat ../package.json 2>/dev/null | grep -E '"next"|"react"|"vue"|"nuxt"' | head -3

If a frontend is found, suggest the matching SDK skill:

Frontend detected Suggest skill Next.js ("next" in package.json) sentry-nextjs-sdk React SPA ("react" without "next") @sentry/react — see docs.sentry.io/platforms/javascript/guides/react/ Vue.js @sentry/vue — see docs.sentry.io/platforms/javascript/guides/vue/ Nuxt @sentry/nuxt — see docs.sentry.io/platforms/javascript/guides/nuxt/

Connecting frontend and backend with the same Sentry project enables distributed tracing — a single trace view spanning browser, .NET server, and any downstream APIs.