Scaffold

/scaffold — Architecture-Aware Feature Scaffolding

What

Generates a complete feature with all required files based on the project's architecture. Never generates half a feature — every scaffold includes the endpoint, handler, validation, DTOs, EF configuration, and at least one integration test as a single unit, written in modern C# 14 (primary constructors, collection expressions, records, sealed handlers, TypedResults).

Supported architectures (file placement maps and code shape templates live in references/architecture-patterns.md):

• Vertical Slice Architecture (VSA) — single-file features in Features/
• Clean Architecture (CA) — files split across Domain, Application, Infrastructure, Api
• DDD + Clean Architecture — aggregate roots, value objects, domain events, plus CA layers
• Modular Monolith — self-contained modules with their own DbContext and integration events

When

• "Scaffold a [feature name]", "create an endpoint for", "add a feature"
• "Generate CRUD for", "add entity", "new module", "scaffold a module"
• Starting a new feature after /plan has produced an approved plan
• Customizing generation templates or defining what a complete slice includes
• Any time the user wants a complete, working feature skeleton

How

Step 1: Detect Architecture

Use the architecture-advisor skill to determine the project's architecture:

• Examine folder structure, project references, and existing patterns
• If architecture is ambiguous, ask the user rather than guessing
• Load the matching architecture skill (vertical-slice, clean-architecture, ddd)

Step 2: Clarify Scope

Confirm with the user before generating (skip anything the plan already answers):

1. Feature/entity name and operations needed — full CRUD or a subset?
2. Key fields and invariants for any new entity
3. Module placement (Modular Monolith only) — existing module or new one?

Step 3: Learn Conventions

Use the convention-learner skill and MCP tools to check:

• Naming patterns (*Handler, *Service, *Endpoint, *Command, *Query)
• Folder structure, file organization, access modifiers, sealed conventions
• Existing validation approach (FluentValidation, data annotations, manual)
• Test project structure and naming (*Tests, *IntegrationTests)

Match what exists. Do not impose new conventions on an established codebase.

Step 4: Generate All Layers

Generate every file the architecture requires, following the templates in references/architecture-patterns.md:

• VSA — read the VSA section: single-file feature + endpoint group + EF config + tests
• Clean Architecture — read the CA section: Mediator command/handler in Application, endpoint in Api
• DDD — read the DDD section: aggregate with invariants and domain events, thin handler
• Modular Monolith — read the Modular Monolith section: module DbContext, DI registration, integration events

The reference also covers the shared shapes every architecture reuses (endpoint group, validator, entity + IEntityTypeConfiguration<T> pair, test fixture) and the anti-patterns to avoid.

Step 5: Completeness Checklist (MANDATORY)

Every scaffolded feature MUST include ALL nine items. Do not skip any:

• Endpoint — IEndpointGroup file with a route group; never wired in Program.cs
• Handler — sealed, primary constructor, one per operation
• Validator — FluentValidation rules with meaning (ranges, required, max lengths), wired via .AddEndpointFilter<ValidationFilter<T>>() on mutating endpoints
• DTOs — records shaped for the consumer, never 1:1 entity mirrors
• EF configuration — IEntityTypeConfiguration<T>; no data annotations on entities
• Integration tests — WebApplicationFactory + Testcontainers, DI replacement via services.RemoveAll<DbContextOptions<T>>()
• OpenAPI metadata — .WithName(), .WithSummary(), .Produces<T>(), .ProducesValidationProblem(), .ProducesProblem(404)
• CancellationToken — on every async method and passed to every async call
• Result pattern — handlers return Result<T>; endpoints map success → TypedResults, failure → ToProblemDetails()

Also verify supporting infrastructure — scaffold it if missing: list endpoints get bounded pagination (page/pageSize, max 50), Program.cs has app.UseExceptionHandler(), and appsettings.json has a connection string.

Step 6: Verify

Prove the scaffold works before reporting done:

dotnet build --no-restoredotnet test --no-build --filter "FullyQualifiedName~{FeatureName}"

If the build or tests fail, fix and re-run before presenting results.

Example

User: /scaffold a Product Catalog feature with CRUD operations
Claude: Detected architecture: Vertical Slice Architecture
Created files:  src/Features/Products/CreateProduct.cs     -- Command + handler + validator  src/Features/Products/GetProduct.cs        -- Query by ID + handler  src/Features/Products/ListProducts.cs      -- Paginated list + handler  src/Features/Products/UpdateProduct.cs     -- Command + handler + validator  src/Features/Products/DeleteProduct.cs     -- Command + handler  src/Features/Products/ProductEndpoints.cs  -- IEndpointGroup, OpenAPI metadata  src/Features/Products/ProductConfig.cs     -- EF Core configuration  tests/Features/Products/CreateProductTests.cs  tests/Features/Products/GetProductTests.cs  tests/Features/Products/ListProductsTests.cs
Checklist: 9/9 | Build: PASS | Tests: PASS
All files follow your existing conventions (sealed handlers,primary constructors, TypedResults return types).

Related

• dotnet-init — Initialize the project and CLAUDE.md before scaffolding features
• vertical-slice — The VSA patterns the VSA scaffold follows
• clean-architecture — Layering rules behind the CA scaffold
• ddd — Aggregate and domain-event patterns behind the DDD scaffold
• project-structure — Where files belong in each architecture