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/agent-skills --skill sentry-dotnet-sdk Download ZIPGitHub19

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. 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+

• ⚡ 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+ 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)

npx @sentry/wizard@latest -i dotnet

The wizard logs you into Sentry, selects your org and project, configures your DSN, and sets up MSBuild symbol upload for readable stack traces in production.

Skip to Verification after running the wizard.

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

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

var host = new HostBuilder()
 .ConfigureFunctionsWorkerDefaults()
 .ConfigureServices(services =>
 {
 services.AddOpenTelemetry().WithTracing(builder =>
 {
 builder
 .AddSentry() // route OTel spans to Sentry
 .AddHttpClientInstrumentation(); // capture outgoing HTTP
 });
 })
 .ConfigureLogging(logging =>
 {
 logging.AddSentry(options =>
 {
 options.Dsn = "___YOUR_DSN___";
 options.Debug = true;
 options.TracesSampleRate = 1.0;
 options.UseOpenTelemetry(); // let OTel drive tracing
 options.DisableSentryHttpMessageHandler = true; // prevent duplicate HTTP spans
 });
 })
 .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. Upload PDB files to unlock full source context.

Step 1: Create a Sentry auth token

Go to sentry.io/settings/auth-tokens/ and create a token with project:releases and org:read scopes.

Step 2: Add MSBuild properties to .csproj or Directory.Build.props:

 
 ___ORG_SLUG___ 
 ___PROJECT_SLUG___ 
 true 
 true 
 true 
 true 
 

Step 3: Set SENTRY_AUTH_TOKEN in CI:

# GitHub Actions
- name: Build & upload symbols
 run: dotnet build -c Release
 env:
 SENTRY_AUTH_TOKEN: ${{ secrets.SENTRY_AUTH_TOKEN }}

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 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>

Config Reference

Core SentryOptions

Option Type Default Env Var Notes Dsn string — SENTRY_DSN Required. SDK disabled if unset. Debug bool false — SDK diagnostic output. Disable in production. DiagnosticLevel SentryLevel Debug — Debug, Info, Warning, Error, Fatal Release string auto SENTRY_RELEASE Auto-detected from assembly version + git SHA Environment string "production" SENTRY_ENVIRONMENT "debug" when debugger attached Dist string — — Build variant. Max 64 chars. SampleRate float 1.0 — Error event sampling rate 0.0–1.0 TracesSampleRate double 0.0 — Transaction sampling. Must be > 0 to enable. TracesSampler Func<SamplingContext, double> — — Per-transaction dynamic sampler; overrides TracesSampleRate ProfilesSampleRate double 0.0 — Fraction of traced transactions to profile. Requires Sentry.Profiling. SendDefaultPii bool false — Include user IP, name, email AttachStacktrace bool true — Attach stack trace to all messages MaxBreadcrumbs int 100 — Max breadcrumbs stored per event IsGlobalModeEnabled bool false* — Auto-true for MAUI, Blazor WASM. Must be true for WPF, WinForms, Console. AutoSessionTracking bool false — *Auto-true for MAUI. Enable for Release Health. CaptureFailedRequests bool true — Auto-capture HTTP client errors CacheDirectoryPath string — — Offline event caching directory ShutdownTimeout TimeSpan — — Max wait for event flush on shutdown HttpProxy string — — Proxy URL for Sentry requests EnableBackpressureHandling bool true — Auto-reduce sample rates on delivery failures

ASP.NET Core Extended Options (SentryAspNetCoreOptions)

Option Type Default Notes MaxRequestBodySize RequestSize None None, Small (~4 KB), Medium (~10 KB), Always MinimumBreadcrumbLevel LogLevel Information Min log level for breadcrumbs MinimumEventLevel LogLevel Error Min log level to send as Sentry event CaptureBlockingCalls bool false Detect .Wait() / .Result threadpool starvation FlushOnCompletedRequest bool false Required for Lambda / serverless IncludeActivityData bool false Capture System.Diagnostics.Activity values

MAUI Extended Options (SentryMauiOptions)

Option Type Default Notes IncludeTextInBreadcrumbs bool false Text from Button, Label, Entry elements. ⚠️ PII risk. IncludeTitleInBreadcrumbs bool false Titles from Window, Page elements. ⚠️ PII risk. IncludeBackgroundingStateInBreadcrumbs bool false Window.Backgrounding event state. ⚠️ PII risk.

Environment Variables

Variable Purpose SENTRY_DSN Project DSN SENTRY_RELEASE App version (e.g. [email protected]) SENTRY_ENVIRONMENT Deployment environment name SENTRY_AUTH_TOKEN MSBuild / sentry-cli symbol upload auth token

ASP.NET Core: use double underscore __ as hierarchy separator:

export Sentry__Dsn="https://..."
export Sentry__TracesSampleRate="0.1"

MSBuild Symbol Upload Properties

Property Type Default Description SentryOrg string — Sentry organization slug SentryProject string — Sentry project slug SentryUploadSymbols bool false Upload PDB files for line numbers in stack traces SentryUploadSources bool false Upload source files for source context SentryCreateRelease bool false Auto-create a Sentry release during build SentrySetCommits bool false Associate git commits with the release SentryUrl string — Self-hosted Sentry URL

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.