Configure Aspire AppHost to emit explicit app config via environment variables; keep app code free of Aspire clients and service discovery.

Aspire Configuration When to Use This Skill Use this skill when: Wiring AppHost resources to application configuration in Aspire based repos Ensuring production configuration is transparent and portable outside of Aspire Avoiding Aspire client/service discovery packages inside application code Designing feature toggles for dev/test without changing app code paths Core Principles 1. AppHost owns Aspire infrastructure packages Aspire Hosting packages belong in AppHost only. App projects should not reference Aspire client/service discovery packages. 2. Explicit configuration only AppHost must translate resource outputs into explicit config keys (env vars). App code binds to IOptions<T or Configuration only. 3. Production parity and transparency Every value injected by AppHost must be representable in production as env vars or config files without Aspire. Avoid opaque service discovery and implicit configuration. Configuration Flow The AppHost is responsible for turning Aspire resources into explicit app settings. The application never consumes Aspire clients or service discovery directly. AppHost Patterns (Explicit Mapping) Example: Database + Blob Storage Key points WithReference(db, "Postgres") sets ConnectionStrings Postgres explicitly. Every external dependency is represented via explicit config keys. The API project only reads Configuration values. App Code Pattern (No Aspire Clients) Application code binds to options and initializes SDKs directly. It never depends on Aspire client packages or service discovery. Do not add Aspire client packages (or AddServiceDiscovery ) to the app. Those are orchestration concerns and should stay in AppHost. Feature Toggles and Test Overrides Keep toggles in config and drive them through AppHost and test fixtures. This maintains parity between dev/test and production configuration. See skills/aspire/integration testing/SKILL.md for patterns on passing configuration overrides into DistributedApplicationTestingBuilder . Do / Don’t Checklist Do Map every Aspire resource output to explicit configuration keys Use IOptions<T with validation for all infrastructure settings Keep AppHost as the only place that references Aspire hosting packages Ensure any AppHost injected value can be set in production env vars Don’t Reference Aspire client/service discovery packages in application projects Rely on opaque service discovery that cannot be mirrored in production Hide configuration behind Aspire only abstractions Related Skills skills/aspire/service defaults/SKILL.md skills/aspire/integration testing/SKILL.md skills/akka/aspire configuration/SKILL.md Resources Aspire AppHost environment configuration: https://learn.microsoft.com/en us/dotnet/aspire/fundamentals/app host Configuration in .NET: https://learn.microsoft.com/en us/dotnet/core/extensions/configuration

aspire-configuration