templates-dotnet/.github/prompts/convert-controller-to-minimal.prompt.md

description, agent

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Convert an MVC controller to Minimal API endpoints following the project's ASP.NET conventions.	agent

Convert Controller to Minimal API

Refactor an MVC controller into Minimal API endpoints aligned with aspnet-api.instructions.md.

Input

Path to the controller file (e.g., src/MyApi/Controllers/OrdersController.cs). Ask if not provided.

Steps

1. Analyse the Controller

For each action method, capture:

• HTTP verb and route template.
• Parameter binding sources ([FromRoute], [FromQuery], [FromBody], [FromServices]).
• Return type and possible status codes.
• Filters / attributes ([Authorize], [ProducesResponseType], etc.).
• Async signature and CancellationToken usage.

2. Produce a Migration Plan

Present a table to the user before writing any code:

| Action | New endpoint | Notes (auth, filters, response types) |

Ask for confirmation or adjustments.

3. Generate the Endpoint File

Create <Resource>Endpoints.cs next to the controller, following the conventions:

• Static class with a MapXEndpoints(this IEndpointRouteBuilder) extension.
• MapGroup("/api/v{apiVersion}/{resource}") with shared .WithTags(...).
• Use TypedResults for every return path.
• Use [AsParameters] for complex parameter sets.
• Use CancellationToken on every async lambda.
• Errors return ProblemDetails via TypedResults.Problem(...).
• Endpoint lambdas stay thin; delegate to injected services.

4. Wire Up Registration

In Program.cs, replace MapControllers() (or supplement it) with the new MapXEndpoints() call. If the controller was the last one, also remove AddControllers().

5. Migrate Tests

For each test targeting the controller, port it to use WebApplicationFactory against the new endpoint. Keep the file name and test names; update the arrange/act sections only.

6. Delete the Controller

Only after the new endpoints + tests pass. Run dotnet build and dotnet test before deletion.

7. Update README

If the project's README.md documented the old controller routes, update it in the same commit (per copilot-instructions.md).

Guardrails

• Do not change behaviour while converting — refactor first, behaviour changes go in a separate commit.
• If a controller uses filters or model binders without a Minimal API equivalent, surface the gap and ask before inventing one.