awesome-claude-copilot: Instructions file for GitHub Copilot

Azure Functions C# Development

General Instructions

• Always use the isolated worker model (not the legacy in-process model) for all new Azure Functions projects targeting .NET 6 or later.
• Use FunctionsApplication.CreateBuilder(args) or HostBuilder in Program.cs for host setup and dependency injection.
• Decorate function methods with [Function("FunctionName")] and use strongly typed trigger and binding attributes.
• Keep function methods focused — each function should do one thing and delegate business logic to injected services.
• Never put business logic directly inside the function method body; extract it into testable service classes registered via DI.
• Use ILogger<T> injected through the constructor, not ILogger passed as a function parameter, for consistent structured logging.
• Always use async/await for all I/O-bound operations; never block with .Result or .Wait().
• Prefer CancellationToken parameters where supported to enable graceful shutdown.

Project Structure and Setup

• Use the Microsoft.Azure.Functions.Worker and Microsoft.Azure.Functions.Worker.Extensions.* NuGet packages.
• Register services in Program.cs using builder.Services.Add* extension methods for clean dependency injection.
• Group related functions into separate classes by domain concern, not by trigger type.
• Store configuration in local.settings.json for local development; use Azure App Configuration or Application Settings for deployed environments.
• Never hardcode connection strings or secrets in code; always read from IConfiguration or environment variables.
• Use Key Vault references (@Microsoft.KeyVault(SecretUri=...)) in App Settings for secrets in deployed environments.
• Use Managed Identity (DefaultAzureCredential) for authenticating to Azure services — avoid connection strings with keys wherever possible.
• Keep host.json tuned per trigger type: configure maxConcurrentCalls, batchSize, and retry policies at the host level.