Create a new use case architecture plan

Review and finalize the use case implementation plan

Asks the AI Agent to report it's findings on the previous use case implementation coding session

Instructs AI Agent to read the use case, the implementation plan and write the code

Reviews the deployment process for any issues and/or lessons learned

Deploys the application

Create a new git commit using conventional commit style messages

Asks the AI Agent for suggestions on improving the prompt engineering

Explores back-end testing for a use case

Verifies the UI tests

Create a new world-class use case document

Review a use case

Expert in DocFX documentation system, markdown formatting, and Akka.NET documentation standards. Handles DocFX-specific syntax, API references, build validation, and compliance with project documentation guidelines. Integrates markdownlint and DocFX compilation checks.

Analyzes .NET project context, requirements, and constraints to recommend architecture approaches, framework choices, and design patterns. Triggers on: what framework to use, how to structure a project, recommend an approach, architecture review.

WHEN analyzing ASP.NET Core middleware, request pipelines, minimal API design, DI lifetime selection, or diagnostic scenarios. WHEN NOT handling Blazor/Razor (use dotnet-blazor-specialist), security auditing (use dotnet-security-reviewer), or async internals (use dotnet-async-performance-specialist).

WHEN analyzing async/await performance, ValueTask correctness, ConfigureAwait decisions, IO.Pipelines, ThreadPool tuning, or Channel selection in .NET code. WHEN NOT profiling interpretation (use dotnet-performance-analyst) or thread sync bugs (use dotnet-csharp-concurrency-specialist).

WHEN designing .NET benchmarks, reviewing benchmark methodology, or validating measurement correctness. Avoids dead code elimination, measurement bias, and common BenchmarkDotNet pitfalls. Triggers on: design a benchmark, review benchmark, benchmark pitfalls, how to measure, memory diagnoser setup.

Guides Blazor development across all hosting models (Server, WASM, Hybrid, Auto). Component design, state management, authentication, and render mode selection. Triggers on: blazor component, render mode, blazor auth, editform, blazor state.

WHEN planning cloud deployment, .NET Aspire orchestration, AKS configuration, multi-stage CI/CD pipelines, distributed tracing, or infrastructure-as-code for .NET apps. WHEN NOT general architecture (use dotnet-architect), container image optimization (use dotnet-containers skill), or security auditing (use dotnet-security-reviewer).

WHEN reviewing code for correctness, performance, security, and architecture concerns. Triages findings and routes to specialist agents for deep analysis. Triggers on: review this, code review, PR review, what's wrong with this code.

Expert in .NET concurrency, threading, and race condition analysis. Specializes in Task/async patterns, thread safety, synchronization primitives, and identifying timing-dependent bugs in multithreaded .NET applications. Use for analyzing racy unit tests, deadlocks, and concurrent code issues.

WHEN debugging race conditions, deadlocks, thread safety issues, concurrent access bugs, lock contention, async races, parallel execution problems, or synchronization issues in .NET code. WHEN NOT general async/await questions (use dotnet-csharp-async-patterns skill instead).

WHEN generating documentation for a .NET project. Analyzes project structure, recommends doc tooling, generates Mermaid architecture diagrams, writes XML doc comment skeletons, and scaffolds GitHub-native docs. Triggers on: generate docs, add documentation, create README, document this project, add XML docs, generate architecture diagram.

WHEN building .NET MAUI apps. Platform-specific development, Xamarin migration, Native AOT on iOS/Catalyst, .NET 11 improvements. Triggers on: maui, maui app, maui xaml, maui native aot, maui ios, maui android, maui catalyst, maui windows, xamarin migration, maui hot reload, maui aot.

WHEN analyzing .NET profiling data, benchmark results, GC behavior, or diagnosing performance bottlenecks. Interprets flame graphs, heap dumps, and benchmark comparisons. Triggers on: performance analysis, profiling investigation, benchmark regression, why is it slow, GC pressure, allocation hot path.

WHEN reviewing .NET code for security vulnerabilities, OWASP compliance, secrets exposure, or cryptographic misuse. Read-only analysis agent -- does not modify code.

WHEN designing test architecture, choosing test types (unit/integration/E2E), managing test data, testing microservices, or structuring test projects. WHEN NOT benchmarking (use dotnet-benchmark-designer), security auditing (use dotnet-security-reviewer), or UI-framework-specific testing (use Blazor/MAUI/Uno specialists).

WHEN building cross-platform Uno Platform apps. Project setup, target configuration, Extensions ecosystem, MVUX patterns, Toolkit controls, theming, MCP integration. Triggers on: uno platform, uno app, uno wasm, uno mobile, uno desktop, uno extensions, mvux, uno toolkit, uno themes, cross-platform uno, uno embedded.

Browser automation CLI for AI agents. Use when the user needs to interact with websites, including navigating pages, filling forms, clicking buttons, taking screenshots, extracting data, testing web apps, or automating any browser task. Triggers include requests to "open a website", "fill out a form", "click a button", "take a screenshot", "scrape data from a page", "test this web app", "login to a site", "automate browser actions", or any task requiring programmatic web interaction.

Production-grade patterns for ASP.NET Core Identity in Razor Pages and web apps. Covers setup, customization, security hardening, auth flows, roles/claims, external providers, and integration best practices for .NET 8+ / .NET 9+. Use when implementing authentication and authorization in ASP.NET Core applications, configuring ASP.NET Core Identity, setting up external login providers, or managing roles and claims.

Configure Aspire AppHost to emit explicit app config via environment variables while keeping app code free of Aspire clients and service discovery. Use when wiring AppHost resources to application configuration, ensuring production configuration is transparent and portable outside of Aspire, or avoiding Aspire client packages inside application code.

Write integration tests using .NET Aspire's testing facilities with xUnit. Covers test fixtures, distributed application setup, endpoint discovery, and patterns for testing ASP.NET Core apps with real dependencies. Use when writing integration tests for .NET Aspire applications, testing ASP.NET Core apps with real database connections, or verifying service-to-service communication in distributed applications.

Test email sending locally using Mailpit with .NET Aspire. Captures all outgoing emails without sending them. View rendered HTML, inspect headers, and verify delivery in integration tests. Use when testing email delivery locally without sending real emails, setting up email infrastructure in .NET Aspire, or writing integration tests that verify emails are sent.

Create a shared ServiceDefaults project for Aspire applications. Centralizes OpenTelemetry, health checks, resilience, and service discovery configuration across all services. Use when building Aspire-based distributed applications, needing consistent observability across services, or configuring HttpClient resilience and service discovery.

Hosted services, background jobs, outbox patterns, and graceful shutdown handling for ASP.NET Core applications. Includes patterns for reliable job processing, distributed systems, and lifecycle management. Use when implementing background processing in ASP.NET Core applications, handling outbox patterns for reliable message delivery, or managing graceful service shutdown.

Production-grade Bootstrap 5.3 patterns for building modern, responsive web UIs in HTML and ASP.NET Core Razor Pages/Views. Use when creating or styling web pages, layouts, navigation, forms, cards, modals, tables, or any UI component with Bootstrap 5. Covers the grid system, responsive breakpoints, utility classes, color modes (dark/light), accessibility, and integration with ASP.NET Core tag helpers and Razor syntax. Trigger on any task involving Bootstrap CSS classes, responsive HTML layouts, Razor Page UI design, or front-end styling for .NET web applications.

Comprehensive caching patterns for ASP.NET Core Razor Pages applications. Covers output caching, response caching, memory caching, distributed caching with Redis, cache invalidation strategies, and HybridCache (.NET 9+). Use when implementing caching in Razor Pages applications, choosing between memory and distributed caching, or optimizing application performance with caching.

Analyze code coverage and CRAP (Change Risk Anti-Patterns) scores to identify high-risk code. Use OpenCover format with ReportGenerator for Risk Hotspots showing cyclomatic complexity and untested code paths. Use when evaluating code quality and test coverage before changes, identifying high-risk code that needs refactoring or testing, setting up coverage collection for a .NET project, or establishing coverage thresholds for CI/CD pipelines.

Design stable, compatible public APIs using extend-only design principles. Manage API compatibility, wire compatibility, versioning, naming conventions, parameter ordering, and return types for NuGet packages and distributed systems. Use when designing public APIs for NuGet packages or libraries, making changes to existing public APIs, planning wire format changes for distributed systems, or reviewing pull requests for breaking changes.

Write modern, high-performance C# code using records, pattern matching, value objects, async/await, Span<T>/Memory<T>, and best-practice API design patterns. Emphasizes functional-style programming with C# 12+ features. Use when writing new C# code or refactoring existing code, designing public APIs for libraries or services, optimizing performance-critical code paths, or building async/await-heavy applications.

Choosing the right concurrency abstraction in .NET - from async/await for I/O to Channels for producer/consumer to Akka.NET for stateful entity management. Covers both high-level abstractions and low-level synchronization primitives. Use when deciding how to handle concurrent operations in .NET, evaluating whether to use async/await, Channels, or Akka.NET, or managing state across multiple concurrent entities.

Run single-file C# programs as scripts for quick experimentation, prototyping, and concept testing. Use when the user wants to write and execute a small C# program without creating a full project.

Design .NET types for performance. Covers struct vs class decision matrix, sealed by default, readonly structs, ref struct and Span/Memory selection, FrozenDictionary, ValueTask, and collection return types. Use when designing new types and APIs, reviewing code for performance issues, choosing between class, struct, and record, or working with collections and enumerables.

Build .NET applications with WolverineFX for messaging, HTTP services, and event sourcing. Use when implementing command handlers, message handlers, HTTP endpoints with WolverineFx.HTTP, transactional outbox patterns, event sourcing with Marten, CQRS architectures, cascading messages, batch message processing, or configuring transports like RabbitMQ, Azure Service Bus, or Amazon SQS.

ASP.NET Core Data Protection API patterns for encryption, key management, and secure data handling in web applications. Use when protecting sensitive data at rest or in transit, managing encryption keys in ASP.NET Core applications, or implementing secure token generation and validation.

Database access patterns for performance. Separate read/write models, avoid N+1 queries, use AsNoTracking, apply row limits, and never do application-side joins. Works with EF Core and Dapper. Use when designing data access layers, optimizing slow database queries, choosing between EF Core and Dapper, or avoiding common performance pitfalls.

Building accessible .NET UI. SemanticProperties, ARIA, AutomationPeer, testing tools per platform.

Adding analyzer packages to a project. Nullable, trimming, AOT compat analyzers, severity config.

Adding CI/CD to a .NET project. GitHub Actions vs Azure DevOps detection, workflow templates.

Adding test infrastructure to a .NET project. Scaffolds xUnit project, coverlet, layout.

Configuring .NET build/test in Azure DevOps. DotNetCoreCLI task, Artifacts, test results.

Designing composable Azure DevOps YAML pipelines. Templates, variable groups, multi-stage, triggers.

Publishing .NET artifacts from Azure DevOps. NuGet push, containers to ACR, pipeline artifacts.

Using ADO-exclusive features. Environments, approvals, service connections, classic releases.

Working with .NET, C#, ASP.NET Core, or related frameworks. Routes to specialist skills.

Generating or modifying .NET code. Common agent mistakes: async, NuGet, deprecated APIs, DI.

Designing AOT-first apps. Source gen over reflection, AOT-safe DI, serialization, factories.

AOT-compiling for WebAssembly. Blazor/Uno WASM AOT, size vs speed, lazy loading, Brotli.

Generating API documentation. DocFX setup, OpenAPI-as-docs, doc-code sync, versioned docs.

Implementing API auth. Identity, OAuth/OIDC, JWT bearer, passkeys (WebAuthn), CORS, rate limiting.

Detecting API changes in CI. PublicApiAnalyzers, Verify snapshots, breaking change enforcement.

Versioning HTTP APIs. Asp.Versioning.Http/Mvc, URL segment, header, query string, sunset.

Organizing APIs at scale. Vertical slices, request pipelines, caching, error handling, idempotency.

Using artifacts output layout. UseArtifactsOutput, ArtifactsPath, impact on CI and Docker.

Using .NET Aspire. AppHost orchestration, service discovery, components, dashboard, health checks.

Writing benchmarks. BenchmarkDotNet setup, memory diagnosers, baselines, result analysis.

Adding auth to Blazor. AuthorizeView, CascadingAuthenticationState, Identity UI, per-model flows.

Building Blazor components. Lifecycle, state management, JS interop, EditForm validation, QuickGrid.

Building Blazor apps. Hosting models, render modes, routing, streaming rendering, prerender.

Testing Blazor components. bUnit rendering, events, cascading params, JS interop mocking.

Interpreting MSBuild output, NuGet errors, or analyzer warnings. Error codes, CI drift fixes.

Diagnosing slow builds or incremental failures. Binary logs, parallel builds, restore.

Using producer/consumer queues. Channel<T>, bounded/unbounded, backpressure, drain patterns

Gating CI on perf regressions. Automated threshold alerts, baseline tracking, trend reports.

Structuring CLI app layers. Command/handler/service separation, clig.dev principles, exit codes.

Choosing CLI output format. AOT vs framework-dependent, RID matrix, single-file, dotnet tool.

Publishing to package managers. Homebrew, apt/deb, winget, Scoop, Chocolatey manifests.

Releasing CLI tools. GitHub Actions build matrix, artifact staging, Releases, checksums.

Deploying .NET containers. Kubernetes probes, Docker Compose for local dev, CI/CD integration.

Containerizing .NET apps. Multi-stage Dockerfiles, SDK container publish (.NET 8+), rootless.

Choosing crypto algorithms, hashing, encryption, or key derivation. AES-GCM, RSA, ECDSA, PQC.

Writing async/await code. Task patterns, ConfigureAwait, cancellation, and common agent pitfalls.

Reviewing C# for logic issues. Anti-patterns, common pitfalls, async misuse, DI mistakes.

Using Options pattern, user secrets, or feature flags. IOptions<T> and FeatureManagement.

Registering or resolving services with MS DI. Keyed services, scopes, decoration, hosted services.

Using records, pattern matching, primary constructors, collection expressions. C# 12-15 by TFM.

Enabling nullable reference types. Annotation strategies, attributes, common agent mistakes.

Creating source generators. IIncrementalGenerator, GeneratedRegex, LoggerMessage, STJ source-gen.

Reading or modifying .csproj files. SDK-style structure, PropertyGroup/ItemGroup, CPM, props.

Choosing a data access approach. EF Core vs Dapper vs ADO.NET decision matrix, performance tradeoffs.

Choosing documentation tooling. Starlight, Docusaurus, DocFX decision tree, migration paths.

Modeling business domains. Aggregates, value objects, domain events, rich models, repositories.

Authoring .editorconfig rules. IDE/CA severity, AnalysisLevel, globalconfig, code style enforcement.

Designing data layer architecture. Read/write split, aggregate boundaries, N+1 governance.

Running C# without a project file (.NET 10 SDK). Directives, CLI commands, migration.

Doing file I/O. FileStream, RandomAccess, FileSystemWatcher, MemoryMappedFile, paths.

Tuning GC and memory. GC modes, LOH/POH, Gen0/1/2, Span/Memory deep patterns, ArrayPool, profiling.

Configuring .NET build/test in GitHub Actions. setup-dotnet, NuGet caching, test reporting.

Deploying .NET from GitHub Actions. Azure Web Apps, GitHub Pages, container registries.

Designing GitHub Actions workflows. Reusable workflows, composite actions, matrix builds, caching.

Publishing .NET artifacts from GitHub Actions. NuGet push, container images, signing, SBOM.

Creating GitHub-native docs. README badges, CONTRIBUTING, issue/PR templates, repo metadata.

Creating GitHub Releases for .NET. Release creation, assets, notes, pre-release management.

Building gRPC services. Proto definition, code-gen, ASP.NET Core host, streaming, auth.

Consuming HTTP APIs. IHttpClientFactory, typed/named clients, resilience, DelegatingHandlers.

Validating HTTP request inputs. .NET 10 AddValidation, FluentValidation, ProblemDetails.

Testing with real infrastructure. WebApplicationFactory, Testcontainers, Aspire, fixtures.

Building high-perf network I/O. PipeReader/PipeWriter, backpressure, protocol parsers, Kestrel.

Maintaining library compatibility. Binary/source compat rules, type forwarders, SemVer impact.

Optimizing LINQ queries. IQueryable vs IEnumerable, compiled queries, deferred exec, allocations.

Localizing .NET apps. .resx resources, IStringLocalizer, source generators, pluralization, RTL.

Optimizing MAUI for iOS/Catalyst. Native AOT pipeline, size/startup gains, library gaps, trimming.

Building .NET MAUI apps. Project structure, XAML/MVVM, platform services, current caveats.

Testing .NET MAUI apps. Appium device/emulator testing, XHarness, platform validation.

Creating Mermaid diagrams for .NET. Architecture, sequence, class, deployment, ER, flowcharts.

Building event-driven systems. Pub/sub, competing consumers, DLQ, sagas, delivery guarantees.

Building Minimal APIs. Route groups, endpoint filters, TypedResults, OpenAPI 3.1, organization.

Analyzing .NET code for modernization. Outdated TFMs, deprecated packages, superseded patterns.

Authoring MSBuild targets, props, or conditions. Custom targets, incrementality, Build patterns.

Writing custom MSBuild tasks. ITask, ToolTask, IIncrementalTask, inline tasks, UsingTask.

Packaging MSIX apps. Creation, signing, Store submission, App Installer sideload, auto-update.

Targeting multiple TFMs or using newer C# on older TFMs. Polyfill strategy, API compat.

Publishing Native AOT. PublishAot, ILLink descriptors, P/Invoke, size optimization, containers.

Calling native libraries via P/Invoke. LibraryImport, marshalling, cross-platform resolution.

Creating NuGet packages. SDK-style csproj, source generators, multi-TFM, symbols, signing.

Adding observability. OpenTelemetry traces/metrics/logs, health checks, custom metrics.

Generating OpenAPI docs. MS.AspNetCore.OpenApi (.NET 9+), Swashbuckle migration, NSwag.

Optimizing .NET allocations/throughput. Span, ArrayPool, ref struct, sealed, stackalloc.

Automating browser tests in .NET. Playwright E2E, CI browser caching, trace viewer, codegen.

Diagnosing .NET performance issues. dotnet-counters, dotnet-trace, dotnet-dump, flame graphs.

Navigating .NET solution structure or build configuration. Analyzes .sln, .csproj, CPM.

Building real-time features. SignalR hubs, SSE (.NET 10), JSON-RPC 2.0, gRPC streaming, scaling.

Managing .NET release lifecycle. NBGV versioning, SemVer, changelogs, pre-release, branching.

Adding fault tolerance. Polly v8 + MS.Extensions.Http.Resilience, retry/circuit breaker/timeout.

Authoring Roslyn analyzers. DiagnosticAnalyzer, CodeFixProvider, CodeRefactoring, multi-version.

Creating a new .NET project. Generates solution with CPM, analyzers, editorconfig, SourceLink.

Handling secrets or sensitive configuration. User secrets, environment variables, rotation.

Securing .NET code or reviewing for vulnerabilities. OWASP Top 10 mitigations, pattern warnings.

Building AI/LLM features. Semantic Kernel setup, plugins, prompt templates, memory stores, agents.

Choosing inter-service protocols. REST vs gRPC vs SignalR vs SSE decision matrix, tradeoffs.

Designing classes or refactoring. SOLID, DRY, SRP with C# anti-patterns, fixes, compliance.

Orienting in a .NET solution. Entry points, .sln/.slnx files, dependency graphs, config.

Building rich console output. Spectre.Console: tables, trees, progress, prompts, live displays.

Designing log pipelines. Aggregation, structured queries, sampling, PII scrubbing, correlation.

Using System.CommandLine 2.0. Commands, options, SetAction, custom parsing, middleware, testing.

Building full TUI apps. Terminal.Gui v2: views, layout (Pos/Dim), menus, dialogs, bindings, themes.

Measuring test effectiveness. Coverlet code coverage, Stryker.NET mutation testing, flaky detection.

Deciding how to test .NET code. Unit vs integration vs E2E decision tree, test doubles.

Installing or managing .NET tools. Global, local, manifests, restore, version pinning.

Making apps/libraries trim-safe. Annotations, ILLink descriptors, IL2xxx warnings, IsTrimmable.

Guidelines for writing TUnit tests in .NET, including setup, assertions, async testing, and best practices. Use when writing unit tests with TUnit framework, setting up TUnit in a .NET project, or migrating from other test frameworks to TUnit.

Selecting a .NET UI framework. Decision tree across Blazor, MAUI, Uno, WinUI, WPF, WinForms.

Testing UI across frameworks. Page objects, test selectors, async waits, accessibility.

Using Uno MCP server. Tool detection, search-then-fetch workflow, init rules, fallback, citation.

Building Uno Platform apps. Extensions, MVUX reactive pattern, Toolkit controls, Hot Reload.

Deploying Uno Platform apps. Per-target guidance for WASM, iOS, Android, macOS, Windows, Linux.

Testing Uno Platform apps. Playwright for WASM, platform-specific patterns, runtime heads.

Project has .csproj, global.json, or Directory.Build.props. Detects TFMs and SDK versions.

Upgrading .NET to a newer TFM. LTS-to-LTS, staged through STS, preview, upgrade paths.

Building WinForms on .NET 8+. High-DPI, dark mode (experimental), DI patterns, modernization tips.

Building WinUI 3 apps. Windows App SDK setup, XAML patterns, MSIX/unpackaged deploy, UWP migration.

Migrating desktop apps. WPF/WinForms to .NET 8+, WPF to WinUI or Uno, UWP to WinUI, decision matrix.

Building WPF on .NET 8+. Host builder, MVVM Toolkit, Fluent theme, performance, modern C# patterns.

Writing XML doc comments. Tags, inheritdoc, GenerateDocumentationFile, warning suppression.

Writing xUnit tests. v3 Fact/Theory, fixtures, parallelism, IAsyncLifetime, v2 compatibility.

Entity Framework Core best practices including NoTracking by default, query splitting for navigation collections, migration management, dedicated migration services, interceptors, compiled queries, and connection resiliency. Use when setting up EF Core in a new project, optimizing query performance, managing database migrations, integrating EF Core with .NET Aspire, or debugging change tracking issues.

Comprehensive exception handling patterns for ASP.NET Core Razor Pages applications. Covers global exception handling, ProblemDetails API, custom error pages, exception middleware, and graceful degradation strategies. Use when implementing error handling in Razor Pages applications, configuring global exception middleware, or creating user-friendly error pages and API error responses.

Microsoft.FeatureManagement patterns for feature toggles, gradual rollouts, and A/B testing in ASP.NET Core Razor Pages applications. Use when implementing feature toggles in ASP.NET Core applications, setting up gradual feature rollouts, or configuring A/B testing scenarios with feature flags.

File uploads, streaming, storage abstractions, and secure file handling patterns for ASP.NET Core Razor Pages applications. Use when implementing secure file uploads in Razor Pages, streaming large files, or creating storage abstractions for file operations.

Helps users discover and install agent skills when they ask questions like "how do I do X", "find a skill for X", "is there a skill that can...", or express interest in extending capabilities. This skill should be used when the user is looking for functionality that might exist as an installable skill.

Deploy, configure, and manage applications on the Fly.io platform using flyctl CLI, fly.toml configuration, Fly Machines, Fly Volumes, private networking, secrets, health checks, autoscaling, and GitHub Actions CI/CD. Use when deploying any application to Fly.io, writing or modifying fly.toml configuration, managing Fly Machines or Volumes, configuring networking (public services, private 6PN, Flycast, custom domains, TLS), setting secrets, configuring health checks, setting up autostop/autostart or metrics-based autoscaling, deploying with GitHub Actions, managing Fly Postgres databases, or preparing an app for production on Fly.io.

IHttpClientFactory patterns with Polly for retries, circuit breakers, timeouts, and resilient HTTP communication. Includes best practices for HTTP client configuration and error handling. Use when configuring resilient HTTP clients in ASP.NET Core, implementing retry policies with Polly, or setting up circuit breakers for external service calls.

Best practices for working with .NET local tools, including manifest management, tool installation, and versioning. Use when setting up dotnet-tools.json for a project, installing or updating local tools, or managing tool versions across team members.

Multi-language support, resource files, culture formatting, and globalization patterns for ASP.NET Core Razor Pages applications. Use when implementing multi-language support in ASP.NET Core applications, managing resource files for translations, or formatting dates, numbers, and currencies for different cultures.

Production-grade logging and observability patterns for ASP.NET Core Razor Pages. Covers structured logging with Serilog, correlation IDs, health checks, request logging, OpenTelemetry integration, and diagnostic best practices. Use when setting up structured logging in ASP.NET Core applications, implementing distributed tracing with OpenTelemetry, or configuring health checks and observability.

Configuration patterns using Microsoft.Extensions.Configuration. Covers configuration providers, binding, validation, and best practices for .NET applications. Use when setting up configuration in .NET applications, implementing configuration validation with IValidateOptions, or managing settings across different environments.

Dependency injection patterns and best practices using Microsoft.Extensions.DependencyInjection for .NET applications. Use when configuring DI containers in .NET, choosing between service lifetimes (Singleton, Scoped, Transient), or implementing decorator patterns and service interception.

Custom middleware patterns for ASP.NET Core applications. Covers request/response pipeline, middleware ordering, conditional middleware, IMiddleware factory pattern, IExceptionHandler (.NET 8+), and reusable middleware components. Use when creating custom middleware in ASP.NET Core applications, understanding middleware pipeline ordering, or implementing cross-cutting concerns like logging, authentication, and caching.

Guidelines for creating responsive email templates using MJML framework with .NET Razor syntax integration. Use when building responsive email templates in .NET applications, integrating MJML with Razor views, or creating email layouts that work across email clients.

NuGet package management best practices including versioning strategies, central package management, and dependency resolution. Use when setting up Central Package Management (CPM), managing package versions across multiple projects, or resolving dependency conflicts in .NET solutions.

End-to-end testing patterns for Blazor applications using Playwright, including component testing and page navigation. Use when writing E2E tests for Blazor applications, testing Blazor component interactions with Playwright, or setting up Playwright testing infrastructure for Blazor apps.

Optimize CI/CD pipelines by caching Playwright browser binaries and dependencies to speed up test execution. Use when setting up Playwright in CI/CD pipelines, reducing build times by caching browser binaries, or configuring GitHub Actions or Azure DevOps for Playwright tests.

Guidelines for organizing .NET projects, including solution structure, project references, folder conventions, .slnx format, centralized build properties, and central package management. Use when setting up a new .NET solution with modern best practices, configuring centralized build properties across multiple projects, implementing central package version management, or setting up SourceLink for debugging.

Rate limiting patterns for ASP.NET Core Razor Pages applications. Covers fixed window, sliding window, token bucket algorithms, and distributed rate limiting with Redis. Use when implementing rate limiting in ASP.NET Core applications, choosing between different rate limiting algorithms, or setting up distributed rate limiting with Redis.

Best practices for building production-grade ASP.NET Core Razor Pages applications. Focuses on structure, lifecycle, binding, validation, security, and maintainability in web apps using Razor Pages as the primary UI framework. Use when building Razor Pages applications, designing PageModels and handlers, implementing model binding and validation, or securing Razor Pages with authentication and authorization.

Security headers configuration and best practices for ASP.NET Core Razor Pages applications. Covers CSP, HSTS, X-Frame-Options, and comprehensive security middleware setup. Use when configuring security headers in ASP.NET Core applications, implementing Content Security Policy (CSP), or setting up HSTS and other security-related HTTP headers.

JSON and binary serialization patterns for .NET applications, including System.Text.Json source generators, Protocol Buffers, MessagePack, and AOT-compatible best practices. Use when configuring JSON serialization, choosing between formats, implementing Protocol Buffers for high-performance scenarios, or working with Native AOT.

SignalR integration patterns for real-time communication in ASP.NET Core Razor Pages applications. Use when implementing real-time features in ASP.NET Core applications, setting up SignalR hubs and clients, or managing WebSocket connections and groups.

Guide for creating effective skills. This skill should be used when users want to create a new skill (or update an existing skill) that extends OpenCode's capabilities with specialized knowledge, workflows, or tool integrations.

Code snippets and templates for working with the skills index and marketplace functionality. Use when creating new skills, updating skill index files, or validating skill metadata and structure.

Patterns for detecting and managing code smells and technical debt in .NET applications. Run Slopwatch CLI to detect LLM reward hacking, disabled tests, suppressed warnings, empty catches, and other shortcuts. Use when identifying code smells, running quality gates in CI/CD, or validating LLM-generated code changes.

Patterns for snapshot testing in .NET applications using Verify. Covers API responses, scrubbing non-deterministic values, custom converters, HTTP response testing, email templates, and CI/CD integration. Use when implementing snapshot tests for API responses, verifying UI component renders, detecting unintended changes in serialization output, or approving public API surfaces.

Patterns for using Testcontainers in .NET integration tests to spin up real dependencies like databases and message queues. Use when writing integration tests that require real databases, testing with message brokers like RabbitMQ or Kafka, or isolating test dependencies with Docker containers.

Comprehensive validation patterns for ASP.NET Core applications. Covers FluentValidation integration, DataAnnotations, IValidatableObject, IValidateOptions<T>, MediatR pipeline behavior, and client-side validation. Use when implementing validation in ASP.NET Core applications, setting up FluentValidation, creating custom validators, configuring options validation, or implementing cross-field validation.

Patterns for verifying email snapshots in tests to ensure email content matches expected outputs. Use when testing email rendering in unit tests, verifying MJML template outputs, or ensuring email content consistency across code changes.