gistfile1.txt

Okay, this is a very detailed request! For each of the 20 steps per endpoint, providing an example "payload" can mean different things:
*   For DTO definition steps, the "payload" is the C# code of the DTO.
*   For controller action/service method steps, it could be a snippet of the C# code or an example HTTP request/response if it's a test step.
*   For validation steps, it's typically an invalid HTTP request payload and the expected error response.

I will provide these for the first four endpoints as you listed previously (`GET /stores`, `POST /stores`, `GET /stores/{store_id}`, `DELETE /stores/{store_id}`). This will be quite extensive.

**Important Note on Payloads:**
*   Dates in JSON responses are illustrative and should reflect actual `DateTime.UtcNow` or similar.
*   `continuation_token` values are placeholders. Real tokens would be opaque strings generated by the persistence layer.
*   Error codes (e.g., `validation_error`) should map to the defined enums (`ErrorCode`, `AuthErrorCode`, etc.).
*   The `Store` DTO and common error DTOs are assumed to be defined as per the preliminary step in the previous response.

---

## Endpoint: GET /stores (ListStores)

### Step 1: Create Stores Controller and ListStores Action Method
*   **Goal:** Set up the basic structure for the `StoresController` and the `ListStores` action method.
*   **Example "Payload" (C# Code Snippet - `StoresController.cs` initial structure):**
    ```csharp
    // StoresController.cs
    using Microsoft.AspNetCore.Mvc;
    using System.Threading.Tasks;
    using System.Collections.Generic; // For List
    using Microsoft.AspNetCore.Http; // For StatusCodes

    // Assuming DTOs like ListStoresResponse and Store are in a Models namespace
    // using YourProject.Models; 

    [ApiController]
    public class StoresController : ControllerBase
    {
        // Placeholder for IStoreService dependency
        // private readonly IStoreService _storeService;
        // public StoresController(IStoreService storeService) { _storeService = storeService; }

        [HttpGet("/stores")]
        [Produces("application/json")]
        public async Task<IActionResult> ListStores(
            [FromQuery(Name = "page_size")] int? pageSize, 
            [FromQuery(Name = "continuation_token")] string continuationToken, 
            [FromQuery] string name)
        {
            // Dummy implementation for now
            await Task.CompletedTask;
            var dummyStores = new List<Store> { new Store { Id = "dummy-id", Name = "Dummy Store", CreatedAt = System.DateTime.UtcNow, UpdatedAt = System.DateTime.UtcNow }};
            return Ok(new ListStoresResponse { Stores = dummyStores, ContinuationToken = "dummy-token" });
        }
    }
    ```

### Step 2: Define `ListStoresResponse` DTO
*   **Goal:** Create the C# DTO for the successful response body.
*   **Example "Payload" (C# Code Snippet - `ListStoresResponse.cs`):**
    ```csharp
    // Models/ListStoresResponse.cs
    using System.Collections.Generic;
    using System.Text.Json.Serialization;

    public class ListStoresResponse
    {
        [JsonPropertyName("stores")]
        public List<Store> Stores { get; set; }

        [JsonPropertyName("continuation_token")]
        public string ContinuationToken { get; set; }
    }
    ```

### Step 3: Define `Store` DTO
*   **Goal:** Create the C# DTO for individual store items.
*   **Example "Payload" (C# Code Snippet - `Store.cs`):**
    ```csharp
    // Models/Store.cs
    using System;
    using System.Text.Json.Serialization;

    public class Store
    {
        [JsonPropertyName("id")]
        public string Id { get; set; }

        [JsonPropertyName("name")]
        public string Name { get; set; }

        [JsonPropertyName("created_at")]
        public DateTime CreatedAt { get; set; }

        [JsonPropertyName("updated_at")]
        public DateTime UpdatedAt { get; set; }

        [JsonPropertyName("deleted_at")]
        [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)] // Important for optional fields
        public DateTime? DeletedAt { get; set; }
    }
    ```

### Step 4: Define `IStoreService` Interface
*   **Goal:** Define an interface for the business logic layer.
*   **Example "Payload" (C# Code Snippet - `IStoreService.cs`):**
    ```csharp
    // Services/IStoreService.cs
    using System.Collections.Generic;
    using System.Threading.Tasks;
    // using YourProject.Models; // Assuming Store DTO is here

    public interface IStoreService
    {
        Task<(List<Store> stores, string continuationToken)> ListStoresAsync(int? pageSize, string continuationToken, string nameFilter);
    }
    ```

### Step 5: Implement Mock `StoreService` for Happy Path
*   **Goal:** Create a basic implementation of `IStoreService`.
*   **Example "Payload" (C# Code Snippet - `MockStoreService.cs`):**
    ```csharp
    // Services/MockStoreService.cs
    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Threading.Tasks;
    // using YourProject.Models;

    public class MockStoreService : IStoreService
    {
        private static readonly List<Store> MockData = new List<Store>
        {
            new Store { Id = "01GKNSYMQ4KX71S0N0Z250BZ5X", Name = "FGA Test Store", CreatedAt = DateTime.UtcNow.AddDays(-5), UpdatedAt = DateTime.UtcNow.AddDays(-1) },
            new Store { Id = "01GKNT00ABCD1S0N0Z250CDEFG", Name = "Sample Store", CreatedAt = DateTime.UtcNow.AddDays(-10), UpdatedAt = DateTime.UtcNow.AddDays(-2) },
            new Store { Id = "01GKNT01EFGH1S0N0Z250HIJKL", Name = "Another Store", CreatedAt = DateTime.UtcNow.AddDays(-2), UpdatedAt = DateTime.UtcNow.AddDays(-0) }
        };

        public Task<(List<Store> stores, string continuationToken)> ListStoresAsync(int? pageSize, string currentContinuationToken, string nameFilter)
        {
            var query = MockData.AsEnumerable();

            if (!string.IsNullOrEmpty(nameFilter))
            {
                query = query.Where(s => s.Name != null && s.Name.Equals(nameFilter, StringComparison.OrdinalIgnoreCase));
            }

            // Simple offset-based pagination for mock
            int skip = 0;
            if (!string.IsNullOrEmpty(currentContinuationToken) && int.TryParse(currentContinuationToken, out int parsedSkip))
            {
                skip = parsedSkip;
            }

            var results = query.Skip(skip).ToList();
            int actualPageSize = pageSize.HasValue && pageSize.Value > 0 ? pageSize.Value : 10; // Default to 10
            
            var page = results.Take(actualPageSize).ToList();
            string nextContinuationToken = null;
            if (results.Count > actualPageSize)
            {
                nextContinuationToken = (skip + actualPageSize).ToString();
            }

            return Task.FromResult((page, nextContinuationToken));
        }
    }
    ```

### Step 6: Inject `IStoreService` into `StoresController`
*   **Goal:** Set up dependency injection.
*   **Example "Payload" (C# Code Snippet - `StoresController.cs` constructor and `Program.cs` / `Startup.cs`):**
    ```csharp
    // StoresController.cs (relevant part)
    private readonly IStoreService _storeService;

    public StoresController(IStoreService storeService) // Constructor injection
    {
        _storeService = storeService;
    }

    // Program.cs (for .NET 6+)
    // builder.Services.AddScoped<IStoreService, MockStoreService>();

    // Or Startup.cs (ConfigureServices method for older .NET)
    // services.AddScoped<IStoreService, MockStoreService>();
    ```

### Step 7: Implement Controller Logic for Basic Happy Path (No Query Params)
*   **Goal:** Call the service and return a 200 OK response.
*   **Controller Code in `ListStores`:**
    ```csharp
    // StoresController.cs - ListStores method
    public async Task<IActionResult> ListStores(
        [FromQuery(Name = "page_size")] int? pageSize, 
        [FromQuery(Name = "continuation_token")] string continuationToken, 
        [FromQuery] string name)
    {
        var (stores, nextToken) = await _storeService.ListStoresAsync(pageSize, continuationToken, name);
        var response = new ListStoresResponse
        {
            Stores = stores,
            ContinuationToken = nextToken ?? "" // Ensure continuation token is empty string if null
        };
        return Ok(response);
    }
    ```
*   **Example HTTP Request:**
    `GET /stores`
    `Accept: application/json`
*   **Example HTTP Response (200 OK):**
    ```json
    {
        "stores": [
            {
                "id": "01GKNSYMQ4KX71S0N0Z250BZ5X",
                "name": "FGA Test Store",
                "created_at": "2023-10-22T12:30:45.123Z", // Example UTC DateTime
                "updated_at": "2023-10-26T15:00:00.000Z"
            },
            {
                "id": "01GKNT00ABCD1S0N0Z250CDEFG",
                "name": "Sample Store",
                "created_at": "2023-10-17T08:00:00.000Z",
                "updated_at": "2023-10-25T10:20:30.456Z"
            }
            // ... potentially more stores up to default page size ...
        ],
        "continuation_token": "2" // Example if page_size was 2 and there are more
    }
    ```

### Step 8: Handle `page_size` Query Parameter
*   **Goal:** Read `page_size` and pass to service.
*   **Example HTTP Request:**
    `GET /stores?page_size=1`
    `Accept: application/json`
*   **Example HTTP Response (200 OK):**
    ```json
    {
        "stores": [
            {
                "id": "01GKNSYMQ4KX71S0N0Z250BZ5X",
                "name": "FGA Test Store",
                "created_at": "2023-10-22T12:30:45.123Z",
                "updated_at": "2023-10-26T15:00:00.000Z"
            }
        ],
        "continuation_token": "1" // Next skip would be 1
    }
    ```

### Step 9: Handle `continuation_token` Query Parameter
*   **Goal:** Read `continuation_token` and pass to service.
*   **Example HTTP Request:**
    `GET /stores?page_size=1&continuation_token=1`
    `Accept: application/json`
*   **Example HTTP Response (200 OK):**
    ```json
    {
        "stores": [
            {
                "id": "01GKNT00ABCD1S0N0Z250CDEFG",
                "name": "Sample Store",
                "created_at": "2023-10-17T08:00:00.000Z",
                "updated_at": "2023-10-25T10:20:30.456Z"
            }
        ],
        "continuation_token": "2" // Next skip would be 2
    }
    ```

### Step 10: Handle `name` Query Parameter
*   **Goal:** Read `name` and pass to service for filtering.
*   **Example HTTP Request:**
    `GET /stores?name=Sample%20Store`
    `Accept: application/json`
*   **Example HTTP Response (200 OK):**
    ```json
    {
        "stores": [
            {
                "id": "01GKNT00ABCD1S0N0Z250CDEFG",
                "name": "Sample Store",
                "created_at": "2023-10-17T08:00:00.000Z",
                "updated_at": "2023-10-25T10:20:30.456Z"
            }
        ],
        "continuation_token": "" // Assuming only one store matches this name
    }
    ```

### Step 11: Implement 200 OK Response Type Attribute
*   **Goal:** Add `ProducesResponseType` attribute for 200 OK.
*   **Example "Payload" (C# Code Snippet - `StoresController.cs` decoration):**
    ```csharp
    [HttpGet("/stores")]
    [Produces("application/json")]
    [ProducesResponseType(typeof(ListStoresResponse), StatusCodes.Status200OK)] // This line
    // ... other ProducesResponseType attributes for errors ...
    public async Task<IActionResult> ListStores( /* ... params ... */ ) {/* ... */}
    ```

### Step 12: Implement Input Validation for `page_size`
*   **Goal:** Add validation for `page_size`.
*   **Controller Code Snippet (Conceptual Validation, before service call):**
    ```csharp
    if (pageSize.HasValue && (pageSize.Value <= 0 || pageSize.Value > 100)) // Example max 100
    {
        return BadRequest(new ValidationErrorMessageResponse
        {
            Code = ErrorCode.ValidationError, // From your ErrorCode enum
            Message = "page_size must be an integer between 1 and 100."
        });
    }
    ```
*   **Example HTTP Request (Invalid):**
    `GET /stores?page_size=0`
    `Accept: application/json`
*   **Example HTTP Response (400 Bad Request):**
    ```json
    {
        "code": "validation_error", // Assuming ErrorCode.ValidationError maps to this string
        "message": "page_size must be an integer between 1 and 100."
    }
    ```
*   **ProducesResponseType attribute:**
    `[ProducesResponseType(typeof(ValidationErrorMessageResponse), StatusCodes.Status400BadRequest)]`

### Step 13: Implement Input Validation for `continuation_token` (Optional)
*   **Goal:** Add validation for `continuation_token` format if applicable.
*   **Controller Code Snippet (Conceptual):**
    ```csharp
    // if (!string.IsNullOrEmpty(continuationToken) && !IsValidBase64(continuationToken)) // Example
    // {
    //     return BadRequest(new ValidationErrorMessageResponse { Code = ErrorCode.InvalidContinuationToken, Message = "Invalid continuation_token format." });
    // }
    ```
*   **Example HTTP Request (Potentially Invalid):**
    `GET /stores?continuation_token=!!!INVALID_TOKEN_CHARS!!!`
*   **Example HTTP Response (400 Bad Request if validation fails):**
    ```json
    {
        "code": "invalid_continuation_token",
        "message": "Invalid continuation_token format."
    }
    ```

### Step 14: Implement 401 Unauthenticated Response
*   **Goal:** Ensure 401 for unauthenticated requests.
*   **Example HTTP Request (No Auth):**
    `GET /stores`
    (No `Authorization` header or invalid/expired token)
*   **Example HTTP Response (401 Unauthorized, typically from auth middleware):**
    ```json
    {
        "code": "unauthenticated", // From ErrorCode enum
        "message": "Not authenticated."
    }
    ```
*   **ProducesResponseType attribute:**
    `[ProducesResponseType(typeof(UnauthenticatedResponse), StatusCodes.Status401Unauthorized)]`

### Step 15: Implement 403 Forbidden Response
*   **Goal:** Ensure 403 for unauthorized users.
*   **Example HTTP Request (Authenticated, but Lacks Permission):**
    `GET /stores`
    `Authorization: Bearer valid_token_for_user_without_list_stores_permission`
*   **Example HTTP Response (403 Forbidden, from authorization logic):**
    ```json
    {
        "code": "forbidden", // From AuthErrorCode enum
        "message": "Forbidden."
    }
    ```
*   **ProducesResponseType attribute:**
    `[ProducesResponseType(typeof(ForbiddenResponse), StatusCodes.Status403Forbidden)]`

### Step 16: Implement 404 PathUnknownErrorMessageResponse
*   **Goal:** Correct 404 for incorrect paths (usually framework).
*   **Example HTTP Request:**
    `GET /nonexistentstores`
*   **Example HTTP Response (404 Not Found, example body):**
    ```json
    {
        "code": "undefined_endpoint", // From NotFoundErrorCode enum
        "message": "Request failed due to incorrect path."
    }
    ```
*   **ProducesResponseType attribute (for completeness on `ListStores`):**
    `[ProducesResponseType(typeof(PathUnknownErrorMessageResponse), StatusCodes.Status404NotFound)]`

### Step 17: Implement 409 AbortedMessageResponse
*   **Goal:** Handle transaction conflicts.
*   **Controller Code (Conceptual try-catch):**
    ```csharp
    // try { ... service call ... }
    // catch (TransactionConflictException ex) // Your custom exception
    // {
    //     return StatusCode(StatusCodes.Status409Conflict, new AbortedMessageResponse { Code = "10", Message = "transaction conflict" });
    // }
    ```
*   **Example HTTP Response (409 Conflict, if service throws):**
    ```json
    {
        "code": "10", // As per spec example
        "message": "transaction conflict"
    }
    ```
*   **ProducesResponseType attribute:**
    `[ProducesResponseType(typeof(AbortedMessageResponse), StatusCodes.Status409Conflict)]`

### Step 18: Implement 422 UnprocessableContentMessageResponse
*   **Goal:** Handle request throttling.
*   **Controller Code (Conceptual try-catch):**
    ```csharp
    // try { ... service call ... }
    // catch (ThrottlingException ex) // Your custom exception
    // {
    //     return StatusCode(StatusCodes.Status422UnprocessableEntity, new UnprocessableContentMessageResponse { Code = UnprocessableContentErrorCode.ThrottledTimeoutError, Message = "Request timed out due to excessive request throttling." });
    // }
    ```
*   **Example HTTP Response (422, if service throws):**
    ```json
    {
        "code": "throttled_timeout_error",
        "message": "Request timed out due to excessive request throttling."
    }
    ```
*   **ProducesResponseType attribute:**
    `[ProducesResponseType(typeof(UnprocessableContentMessageResponse), StatusCodes.Status422UnprocessableEntity)]`

### Step 19: Implement 500 InternalErrorMessageResponse
*   **Goal:** Handle unexpected errors.
*   **Controller Code (Conceptual try-catch or global handler):**
    ```csharp
    // try { ... service call ... }
    // catch (Exception ex) { /* log ex */ return StatusCode(StatusCodes.Status500InternalServerError, new InternalErrorMessageResponse { Code = InternalErrorCode.InternalError, Message = "Request failed due to internal server error." }); }
    ```
*   **Example HTTP Response (500, if service throws unhandled exception):**
    ```json
    {
        "code": "internal_error",
        "message": "Request failed due to internal server error."
    }
    ```
*   **ProducesResponseType attribute:**
    `[ProducesResponseType(typeof(InternalErrorMessageResponse), StatusCodes.Status500InternalServerError)]`

### Step 20: Add XML Documentation Comments
*   **Goal:** Add /// XML comments for Swagger.
*   **Example "Payload" (C# Code Snippet with XML comments):**
    ```csharp
    /// <summary>
    /// List all stores.
    /// </summary>
    /// <remarks>
    /// Returns a paginated list of OpenFGA stores and a continuation token to get additional stores.
    /// The continuation token will be empty if there are no more stores.
    /// </remarks>
    /// <param name="pageSize">Optional. The maximum number of stores to return. Defaults to a server-defined limit.</param>
    /// <param name="continuationToken">Optional. A token from a previous response to fetch the next page of stores.</param>
    /// <param name="name">Optional. Filter stores by exact name match.</param>
    /// <response code="200">A successful response containing a list of stores and a continuation token.</response>
    /// <response code="400">Request failed due to invalid input (e.g., invalid page_size).</response>
    /// <response code="401">Not authenticated.</response>
    // ... other response codes documented ...
    [HttpGet("/stores")]
    // ... attributes ...
    public async Task<IActionResult> ListStores(/*...params...*/) {/*...*/}
    ```

---

## Endpoint: POST /stores (CreateStore)

### Step 1: Add CreateStore Action Method to StoresController
*   **Goal:** Define the `CreateStore` action method.
*   **Example "Payload" (C# Code Snippet - in `StoresController.cs`):**
    ```csharp
    [HttpPost("/stores")]
    [Consumes("application/json")]
    [Produces("application/json")]
    public async Task<IActionResult> CreateStore([FromBody] CreateStoreRequest body)
    {
        // Dummy implementation for now
        await Task.CompletedTask;
        var createdStore = new CreateStoreResponse 
        { 
            Id = "newly-created-id", 
            Name = body.Name, 
            CreatedAt = DateTime.UtcNow, 
            UpdatedAt = DateTime.UtcNow 
        };
        return StatusCode(StatusCodes.Status201Created, createdStore);
        // Proper implementation would use:
        // return CreatedAtAction(nameof(GetStore), new { storeId = createdStore.Id }, createdStore);
        // Assuming GetStore action exists
    }
    ```

### Step 2: Define `CreateStoreRequest` DTO
*   **Goal:** Create the C# DTO for the request body.
*   **Example "Payload" (C# Code Snippet - `CreateStoreRequest.cs`):**
    ```csharp
    // Models/CreateStoreRequest.cs
    using System.ComponentModel.DataAnnotations; // For validation attributes
    using System.Text.Json.Serialization;

    public class CreateStoreRequest
    {
        [JsonPropertyName("name")]
        [Required(ErrorMessage = "Store name is required.")]
        [StringLength(100, MinimumLength = 3, ErrorMessage = "Store name must be between 3 and 100 characters.")]
        // Add [RegularExpression] if specific pattern is needed for store names
        public string Name { get; set; }
    }
    ```

### Step 3: Define `CreateStoreResponse` DTO
*   **Goal:** Create the C# DTO for the 201 response body.
*   **Example "Payload" (C# Code Snippet - `CreateStoreResponse.cs`):**
    ```csharp
    // Models/CreateStoreResponse.cs
    using System;
    using System.Text.Json.Serialization;

    public class CreateStoreResponse
    {
        [JsonPropertyName("id")]
        public string Id { get; set; }

        [JsonPropertyName("name")]
        public string Name { get; set; }

        [JsonPropertyName("created_at")]
        public DateTime CreatedAt { get; set; }

        [JsonPropertyName("updated_at")]
        public DateTime UpdatedAt { get; set; }
    }
    ```

### Step 4: Extend `IStoreService` Interface
*   **Goal:** Add method for creating a store.
*   **Example "Payload" (C# Code Snippet - in `IStoreService.cs`):**
    ```csharp
    // Task<CreateStoreResponse> CreateStoreAsync(CreateStoreRequest request);
    // Or if service deals with domain models:
    Task<Store> CreateStoreAsync(string name); // Then controller maps Store to CreateStoreResponse
    ```
    Let's assume the service returns the response DTO for simplicity here:
    ```csharp
    Task<CreateStoreResponse> CreateStoreAsync(CreateStoreRequest request);
    ```

### Step 5: Implement Mock `StoreService.CreateStoreAsync`
*   **Goal:** Add mock implementation.
*   **Example "Payload" (C# Code Snippet - in `MockStoreService.cs`):**
    ```csharp
    public Task<CreateStoreResponse> CreateStoreAsync(CreateStoreRequest request)
    {
        // Simulate ID generation (e.g., ULID or GUID)
        string newId = $"01HMOCKID{Guid.NewGuid().ToString().Substring(0, 8).ToUpper()}"; 
        var newStore = new Store 
        { 
            Id = newId, 
            Name = request.Name, 
            CreatedAt = DateTime.UtcNow, 
            UpdatedAt = DateTime.UtcNow 
        };
        MockData.Add(newStore); // Add to the static list for consistency in mock

        var response = new CreateStoreResponse
        {
            Id = newStore.Id,
            Name = newStore.Name,
            CreatedAt = newStore.CreatedAt,
            UpdatedAt = newStore.UpdatedAt
        };
        return Task.FromResult(response);
    }
    ```

### Step 6: Implement Controller Logic for Happy Path (201 Created)
*   **Goal:** Call service, return 201 Created.
*   **Controller Code in `CreateStore`:**
    ```csharp
    // Update CreateStore method in StoresController
    public async Task<IActionResult> CreateStore([FromBody] CreateStoreRequest body)
    {
        if (!ModelState.IsValid) // Check for validation errors from DTO attributes
        {
            // This will be covered more in step 7, but good to have early
            return BadRequest(ModelState); 
        }

        var createdStoreResponse = await _storeService.CreateStoreAsync(body);
        
        // Assuming a GetStore action exists for the Location header
        return CreatedAtAction("GetStore", new { storeId = createdStoreResponse.Id }, createdStoreResponse);
    }
    ```
*   **Example HTTP Request:**
    `POST /stores`
    `Content-Type: application/json`
    `Accept: application/json`
    ```json
    {
        "name": "My New Awesome Store"
    }
    ```
*   **Example HTTP Response (201 Created):**
    `Status: 201 Created`
    `Location: /stores/01HMOCKIDABCDEFGH` (URL to the newly created resource)
    ```json
    {
        "id": "01HMOCKIDABCDEFGH", // Example new ID
        "name": "My New Awesome Store",
        "created_at": "2023-10-27T10:00:00.000Z",
        "updated_at": "2023-10-27T10:00:00.000Z"
    }
    ```
*   **ProducesResponseType attribute:**
    `[ProducesResponseType(typeof(CreateStoreResponse), StatusCodes.Status201Created)]`

### Step 7: Implement Request Body Validation (`CreateStoreRequest`)
*   **Goal:** Ensure request body is validated.
*   **Controller Code:** (Already partially shown in Step 6 with `ModelState.IsValid`)
    If `CreateStoreRequest` has `[Required]` and `[StringLength]` on `Name`, ASP.NET Core handles this.
*   **Example HTTP Request (Invalid - missing name):**
    `POST /stores`
    `Content-Type: application/json`
    `Accept: application/json`
    ```json
    {}
    ```
*   **Example HTTP Response (400 Bad Request, from model validation):**
    ```json
    {
        "type": "https://tools.ietf.org/html/rfc7231#section-6.5.1", // Standard problem details
        "title": "One or more validation errors occurred.",
        "status": 400,
        "errors": {
            "Name": [
                "Store name is required."
            ]
        }
    }
    ```
    *(To match the spec's `ValidationErrorMessageResponse`, you might need a custom error filter or manually construct it.)*
    If manually constructing:
    ```csharp
    // In CreateStore, if !ModelState.IsValid
    // var errorResponse = new ValidationErrorMessageResponse { Code = ErrorCode.ValidationError, Message = "Validation failed." /* Or more specific */ };
    // Collect errors from ModelState if needed for message.
    // return BadRequest(errorResponse);
    ```
*   **ProducesResponseType attribute:**
    `[ProducesResponseType(typeof(ValidationErrorMessageResponse), StatusCodes.Status400BadRequest)]`

### Step 8: Handle Store Name Conflicts (Conceptual - if names are unique)
*   **Goal:** Handle if service indicates a name conflict.
*   **Mock Service Logic Update (Conceptual):**
    ```csharp
    // In MockStoreService.CreateStoreAsync, before creating:
    // if (MockData.Any(s => s.Name.Equals(request.Name, StringComparison.OrdinalIgnoreCase)))
    // {
    //     throw new StoreNameConflictException($"Store with name '{request.Name}' already exists."); 
    // }
    ```
*   **Controller Code (Conceptual try-catch):**
    ```csharp
    // try { ... service call ... }
    // catch (StoreNameConflictException ex) // Custom exception
    // {
    //     // The spec uses 409 for "transaction conflict". A "resource already exists" is often 409 too.
    //     return StatusCode(StatusCodes.Status409Conflict, new AbortedMessageResponse { Code = "resource_already_exists_placeholder", Message = ex.Message });
    // }
    ```
*   **Example HTTP Request (Conflicting Name):**
    `POST /stores`
    `Content-Type: application/json`
    ```json
    { "name": "FGA Test Store" } // Assuming this name already exists
    ```
*   **Example HTTP Response (409 Conflict):**
    ```json
    {
        "code": "resource_already_exists_placeholder", // Or "10" if mapped generally
        "message": "Store with name 'FGA Test Store' already exists."
    }
    ```

### Step 9: Implement 401 Unauthenticated Response
*   **Goal:** Ensure 401 for unauthenticated requests.
*   **Example HTTP Request (No Auth):**
    `POST /stores`
    `Content-Type: application/json`
    ```json
    { "name": "Store Attempt" }
    ```
*   **Example HTTP Response (401 Unauthorized):**
    ```json
    { "code": "unauthenticated", "message": "Not authenticated." }
    ```
*   **ProducesResponseType attribute:**
    `[ProducesResponseType(typeof(UnauthenticatedResponse), StatusCodes.Status401Unauthorized)]`

### Step 10: Implement 403 Forbidden Response
*   **Goal:** Ensure 403 for unauthorized users.
*   **Example HTTP Request (Auth, No Permission):**
    `POST /stores`
    `Authorization: Bearer valid_token_user_cannot_create_stores`
    `Content-Type: application/json`
    ```json
    { "name": "Forbidden Store" }
    ```
*   **Example HTTP Response (403 Forbidden):**
    ```json
    { "code": "forbidden", "message": "Forbidden." }
    ```
*   **ProducesResponseType attribute:**
    `[ProducesResponseType(typeof(ForbiddenResponse), StatusCodes.Status403Forbidden)]`

### Step 11: Implement 404 PathUnknownErrorMessageResponse (Framework Level)
*   **Goal:** Ensure 404 for incorrect paths.
*   **Example HTTP Request:**
    `POST /nonexistentstores`
    `Content-Type: application/json`
    ```json
    { "name": "Lost Store" }
    ```
*   **Example HTTP Response (404 Not Found):**
    ```json
    { "code": "undefined_endpoint", "message": "Request failed due to incorrect path." }
    ```
*   **ProducesResponseType attribute:**
    `[ProducesResponseType(typeof(PathUnknownErrorMessageResponse), StatusCodes.Status404NotFound)]`

### Step 12: Implement 409 AbortedMessageResponse for Transaction Conflicts
*   **Same as Step 17 for GET /stores, but in the context of `CreateStoreAsync` call.**
*   **Example HTTP Response (409 Conflict):**
    ```json
    { "code": "10", "message": "transaction conflict" }
    ```
*   **ProducesResponseType attribute:**
    `[ProducesResponseType(typeof(AbortedMessageResponse), StatusCodes.Status409Conflict)]`

### Step 13: Implement 422 UnprocessableContentMessageResponse for Throttling
*   **Same as Step 18 for GET /stores, but in the context of `CreateStoreAsync` call.**
*   **Example HTTP Response (422 Unprocessable Entity):**
    ```json
    { "code": "throttled_timeout_error", "message": "Request timed out due to excessive request throttling." }
    ```
*   **ProducesResponseType attribute:**
    `[ProducesResponseType(typeof(UnprocessableContentMessageResponse), StatusCodes.Status422UnprocessableEntity)]`

### Step 14: Implement 500 InternalErrorMessageResponse
*   **Same as Step 19 for GET /stores, but in the context of `CreateStoreAsync` call.**
*   **Example HTTP Response (500 Internal Server Error):**
    ```json
    { "code": "internal_error", "message": "Request failed due to internal server error." }
    ```
*   **ProducesResponseType attribute:**
    `[ProducesResponseType(typeof(InternalErrorMessageResponse), StatusCodes.Status500InternalServerError)]`

### Step 15: Refine `CreateStoreRequest` Name Validation
*   **Goal:** Apply specific constraints to `Name`.
*   **Example (C# in `CreateStoreRequest.cs`):**
    ```csharp
    [JsonPropertyName("name")]
    [Required]
    [StringLength(64, MinimumLength = 3)]
    [RegularExpression("^[a-zA-Z0-9_-]+$", ErrorMessage = "Store name can only contain alphanumeric characters, underscores, and hyphens.")]
    public string Name { get; set; }
    ```
*   **Example HTTP Request (Invalid Name Pattern):**
    `POST /stores`
    `Content-Type: application/json`
    ```json
    { "name": "My Store!" }
    ```
*   **Example HTTP Response (400 Bad Request):**
    ```json
    {
        // ... standard problem details ...
        "errors": {
            "Name": [ "Store name can only contain alphanumeric characters, underscores, and hyphens." ]
        }
    }
    ```

### Step 16: Ensure `CreatedAt` and `UpdatedAt` are set by Service
*   **Goal:** Verify service sets timestamps.
*   **Acceptance Criteria Check (in test):** After a successful POST, examine the `created_at` and `updated_at` fields in the JSON response. They should be recent and typically equal on creation.
*   **Example "Payload" (Part of the 201 Response shown in Step 6):**
    `"created_at": "2023-10-27T10:00:00.000Z", "updated_at": "2023-10-27T10:00:00.000Z"`

### Step 17: Idempotency Considerations
*   **Goal:** Document non-idempotent nature.
*   **Example Test Scenario "Payloads":**
    1.  **Request 1:**
        `POST /stores` with `{"name": "idempotency-test-store"}`
        **Response 1:** `201 Created` with ID `store-A`
    2.  **Request 2 (Identical):**
        `POST /stores` with `{"name": "idempotency-test-store"}`
        **Response 2 (if name unique constraint):** `409 Conflict` (message: "Store with name 'idempotency-test-store' already exists.")
        **Response 2 (if names not unique):** `201 Created` with a *new* ID `store-B`

### Step 18: Logging for Store Creation
*   **Goal:** Add logging.
*   **Example Log Output (Conceptual):**
    *   Success: `INFO: Store created successfully. StoreID: '01HMOCKIDABCDEFGH', Name: 'My New Awesome Store'.`
    *   Validation Failure: `WARN: Store creation failed validation for Name: 'My Store!'. Errors: Store name can only contain...`
    *   Service Error: `ERROR: Failed to create store 'ErrorProne Store' due to TransactionConflictException.`

### Step 19: Test with Max `Name` Length
*   **Goal:** Test name length boundaries.
*   **Example HTTP Request (Name at max length, e.g., 64 chars):**
    `POST /stores`
    `Content-Type: application/json`
    ```json
    { "name": "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_-" } // 64 chars
    ```
    **Expected Response:** `201 Created`
*   **Example HTTP Request (Name exceeding max length):**
    `POST /stores`
    `Content-Type: application/json`
    ```json
    { "name": "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_--toolong" } // >64 chars
    ```
    **Expected Response:** `400 Bad Request` (due to `StringLength` validation).

### Step 20: Add XML Documentation Comments
*   **Goal:** Add /// XML comments.
*   **Example "Payload" (C# Code Snippet):**
    ```csharp
    /// <summary>
    /// Create a store.
    /// </summary>
    /// <remarks>
    /// Create a unique OpenFGA store which will be used to store authorization models and relationship tuples.
    /// </remarks>
    /// <param name="body">The request body containing the details of the store to create.</param>
    /// <response code="201">A successful response, returning the details of the created store.</response>
    /// <response code="400">Request failed due to invalid input (e.g., missing name, invalid name format).</response>
    // ... other response codes documented ...
    [HttpPost("/stores")]
    // ... attributes ...
    public async Task<IActionResult> CreateStore([FromBody] CreateStoreRequest body) {/*...*/}
    ```

---

## Endpoint: GET /stores/{store_id} (GetStore)

Many error response payloads (`ValidationErrorMessageResponse`, `UnauthenticatedResponse`, etc.) will be structurally identical to those in `GET /stores`. The main differences will be in the happy path and the `store_id` specific validation.

### Step 1: Add GetStore Action Method to StoresController
*   **Goal:** Define the `GetStore` action method.
*   **Example "Payload" (C# Code Snippet - in `StoresController.cs`):**
    ```csharp
    [HttpGet("/stores/{storeId}")] // Note: parameter name matches method argument
    [Produces("application/json")]
    public async Task<IActionResult> GetStore([FromRoute] string storeId)
    {
        // Dummy implementation for now
        await Task.CompletedTask;
        if (storeId == "existing-id")
        {
            return Ok(new GetStoreResponse { Id = storeId, Name = "Found Store", CreatedAt = DateTime.UtcNow, UpdatedAt = DateTime.UtcNow });
        }
        return NotFound(new PathUnknownErrorMessageResponse { Code = NotFoundErrorCode.StoreIdNotFound, Message = "Store not found." });
    }
    ```

### Step 2: Define `GetStoreResponse` DTO
*   **Goal:** Create DTO for success (structurally same as `Store` DTO).
*   **Example "Payload" (C# Code Snippet - `GetStoreResponse.cs`):**
    ```csharp
    // Models/GetStoreResponse.cs 
    // This is identical to the Store DTO as per the spec.
    // You can either reuse the Store DTO or define GetStoreResponse explicitly.
    // For explicitness:
    using System;
    using System.Text.Json.Serialization;

    public class GetStoreResponse
    {
        [JsonPropertyName("id")]
        public string Id { get; set; }

        [JsonPropertyName("name")]
        public string Name { get; set; }

        [JsonPropertyName("created_at")]
        public DateTime CreatedAt { get; set; }

        [JsonPropertyName("updated_at")]
        public DateTime UpdatedAt { get; set; }

        [JsonPropertyName("deleted_at")]
        [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
        public DateTime? DeletedAt { get; set; }
    }
    ```

### Step 3: Extend `IStoreService` Interface
*   **Goal:** Add method for retrieving a store.
*   **Example "Payload" (C# Code Snippet - in `IStoreService.cs`):**
    ```csharp
    Task<GetStoreResponse?> GetStoreAsync(string storeId); // Nullable if not found
    ```

### Step 4: Implement Mock `StoreService.GetStoreAsync`
*   **Goal:** Add mock implementation.
*   **Example "Payload" (C# Code Snippet - in `MockStoreService.cs`):**
    ```csharp
    public Task<GetStoreResponse?> GetStoreAsync(string storeId)
    {
        var store = MockData.FirstOrDefault(s => s.Id == storeId);
        if (store == null)
        {
            return Task.FromResult<GetStoreResponse?>(null);
        }
        // Map Store to GetStoreResponse (they are identical here)
        var response = new GetStoreResponse 
        {
            Id = store.Id,
            Name = store.Name,
            CreatedAt = store.CreatedAt,
            UpdatedAt = store.UpdatedAt,
            DeletedAt = store.DeletedAt
        };
        return Task.FromResult<GetStoreResponse?>(response);
    }
    ```

### Step 5: Implement Controller Logic for Happy Path (200 OK)
*   **Goal:** Call service, return 200 OK if found.
*   **Controller Code in `GetStore`:**
    ```csharp
    public async Task<IActionResult> GetStore([FromRoute] string storeId)
    {
        // Basic validation (more in step 7)
        if (string.IsNullOrWhiteSpace(storeId))
        {
            return BadRequest(new ValidationErrorMessageResponse { Code = ErrorCode.StoreIdInvalidLength, Message = "Store ID cannot be empty." });
        }

        var storeResponse = await _storeService.GetStoreAsync(storeId);
        if (storeResponse == null)
        {
            return NotFound(new PathUnknownErrorMessageResponse { Code = NotFoundErrorCode.StoreIdNotFound, Message = $"Store with ID '{storeId}' not found." });
        }
        return Ok(storeResponse);
    }
    ```
*   **Example HTTP Request:**
    `GET /stores/01GKNSYMQ4KX71S0N0Z250BZ5X` (an existing ID from mock data)
    `Accept: application/json`
*   **Example HTTP Response (200 OK):**
    ```json
    {
        "id": "01GKNSYMQ4KX71S0N0Z250BZ5X",
        "name": "FGA Test Store",
        "created_at": "2023-10-22T12:30:45.123Z",
        "updated_at": "2023-10-26T15:00:00.000Z"
        // "deleted_at" would be present if set
    }
    ```
*   **ProducesResponseType attribute:**
    `[ProducesResponseType(typeof(GetStoreResponse), StatusCodes.Status200OK)]`

### Step 6: Handle Store Not Found (404 PathUnknownErrorMessageResponse)
*   **Goal:** If service indicates not found, return 404.
*   **Controller Code:** (Shown in Step 5 `if (storeResponse == null)`)
*   **Example HTTP Request:**
    `GET /stores/non-existent-id-123`
    `Accept: application/json`
*   **Example HTTP Response (404 Not Found):**
    ```json
    {
        "code": "store_id_not_found", // From NotFoundErrorCode enum
        "message": "Store with ID 'non-existent-id-123' not found."
    }
    ```
*   **ProducesResponseType attribute:**
    `[ProducesResponseType(typeof(PathUnknownErrorMessageResponse), StatusCodes.Status404NotFound)]`

### Step 7: Implement Input Validation for `store_id`
*   **Goal:** Validate `store_id` format/length.
*   **Controller Code (Conceptual validation):**
    ```csharp
    // In GetStore, before service call:
    // const int MaxStoreIdLength = 50; // Example
    // if (storeId.Length > MaxStoreIdLength)
    // {
    //    return BadRequest(new ValidationErrorMessageResponse { Code = ErrorCode.StoreIdInvalidLength, Message = $"Store ID exceeds maximum length of {MaxStoreIdLength} characters." });
    // }
    // if (!IsValidUlidFormat(storeId)) // If IDs are ULIDs
    // {
    //    return BadRequest(new ValidationErrorMessageResponse { Code = ErrorCode.ValidationError, Message = "Invalid Store ID format." });
    // }
    ```
*   **Example HTTP Request (Invalid ID - too long or bad format):**
    `GET /stores/this-id-is-way-too-long-for-our-system-and-should-fail-validation-xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx`
*   **Example HTTP Response (400 Bad Request):**
    ```json
    {
        "code": "store_id_invalid_length", // Or general validation_error
        "message": "Store ID exceeds maximum length of 50 characters."
    }
    ```
*   **ProducesResponseType attribute:**
    `[ProducesResponseType(typeof(ValidationErrorMessageResponse), StatusCodes.Status400BadRequest)]`

### Step 8 to 12: Error Responses (401, 403, 409, 422, 500)
*   **Payloads for these error responses will be structurally identical to those in `GET /stores` (Steps 14, 15, 17, 18, 19 respectively).** The trigger would be the same (auth failure, permission denial, service throwing specific exceptions during `_storeService.GetStoreAsync(storeId)`).
*   Ensure corresponding `ProducesResponseType` attributes are added.

### Step 13: Test `store_id` Path Parameter Binding
*   **No direct "payload" other than the URL itself.**
*   **Test:** Make a request like `GET /stores/my-actual-id-value`. Debug or log within the `GetStore` action method to confirm the `storeId` parameter received is indeed `"my-actual-id-value"`.

### Step 14: Verify `DeletedAt` Field Handling
*   **Goal:** Ensure `DeletedAt` is correct.
*   **Setup:** Mock a store that is soft-deleted:
    ```csharp
    // In MockStoreService MockData:
    // new Store { Id = "deleted-store-01", Name = "Old Deleted Store", ..., DeletedAt = DateTime.UtcNow.AddDays(-20) }
    ```
*   **Example HTTP Request:**
    `GET /stores/deleted-store-01`
*   **Example HTTP Response (200 OK):**
    ```json
    {
        "id": "deleted-store-01",
        "name": "Old Deleted Store",
        "created_at": "...",
        "updated_at": "...",
        "deleted_at": "2023-10-07T10:00:00.000Z" // Example past date
    }
    ```
*   **Example HTTP Request (Active Store):**
    `GET /stores/01GKNSYMQ4KX71S0N0Z250BZ5X`
*   **Example HTTP Response (200 OK):** (deleted_at should be absent if null)
    ```json
    {
        "id": "01GKNSYMQ4KX71S0N0Z250BZ5X",
        "name": "FGA Test Store",
        // ... other fields ...
        // "deleted_at": null // This field would be omitted by JsonIgnoreCondition.WhenWritingNull
    }
    ```

### Steps 15-19: Advanced Tests (Case Sensitivity, Special Chars, Logging, Empty ID, Concurrency)
*   These steps involve specific test scenarios rather than distinct request/response "payloads" beyond what's already covered. For logging, the payload is the log message format. For concurrency, it's more about test setup and observed behavior.

### Step 20: Add XML Documentation Comments
*   **Goal:** Add /// XML comments.
*   **Example "Payload" (C# Code Snippet):**
    ```csharp
    /// <summary>
    /// Get a store.
    /// </summary>
    /// <remarks>
    /// Returns an OpenFGA store by its identifier.
    /// </remarks>
    /// <param name="storeId">The identifier of the store to retrieve.</param>
    /// <response code="200">A successful response, returning the details of the store.</response>
    /// <response code="400">Request failed due to invalid input (e.g., invalid store_id format).</response>
    /// <response code="404">Store not found.</response>
    // ... other response codes documented ...
    [HttpGet("/stores/{storeId}")]
    // ... attributes ...
    public async Task<IActionResult> GetStore([FromRoute] string storeId) {/*...*/}
    ```

---

## Endpoint: DELETE /stores/{store_id} (DeleteStore)

### Step 1: Add DeleteStore Action Method to StoresController
*   **Goal:** Define `DeleteStore` action.
*   **Example "Payload" (C# Code Snippet - in `StoresController.cs`):**
    ```csharp
    [HttpDelete("/stores/{storeId}")]
    public async Task<IActionResult> DeleteStore([FromRoute] string storeId)
    {
        // Dummy implementation for now
        await Task.CompletedTask;
        if (storeId == "existing-id-to-delete")
        {
            return NoContent(); // 204
        }
        return NotFound(new PathUnknownErrorMessageResponse { Code = NotFoundErrorCode.StoreIdNotFound, Message = "Store not found for deletion." });
    }
    ```

### Step 2: Extend `IStoreService` Interface for Delete
*   **Goal:** Add delete method to service.
*   **Example "Payload" (C# Code Snippet - in `IStoreService.cs`):**
    ```csharp
    // Returns true if found and deleted, false if not found.
    // Could also be Task and throw a NotFoundException.
    Task<bool> DeleteStoreAsync(string storeId); 
    ```

### Step 3: Implement Mock `StoreService.DeleteStoreAsync`
*   **Goal:** Add mock delete implementation.
*   **Example "Payload" (C# Code Snippet - in `MockStoreService.cs`):**
    ```csharp
    public Task<bool> DeleteStoreAsync(string storeId)
    {
        var store = MockData.FirstOrDefault(s => s.Id == storeId);
        if (store == null)
        {
            return Task.FromResult(false); // Not found
        }
        // Simulate soft delete or removal
        // If soft delete: store.DeletedAt = DateTime.UtcNow;
        MockData.Remove(store); // For hard delete in mock
        return Task.FromResult(true); // Found and "deleted"
    }
    ```

### Step 4: Implement Controller Logic for Happy Path (204 No Content)
*   **Goal:** Call service, return 204 No Content.
*   **Controller Code in `DeleteStore`:**
    ```csharp
    public async Task<IActionResult> DeleteStore([FromRoute] string storeId)
    {
        // Basic validation
        if (string.IsNullOrWhiteSpace(storeId))
        {
            return BadRequest(new ValidationErrorMessageResponse { Code = ErrorCode.StoreIdInvalidLength, Message = "Store ID cannot be empty." });
        }

        bool deleted = await _storeService.DeleteStoreAsync(storeId);
        if (!deleted)
        {
            // If service returns false for not found, map to 404.
            // If service throws NotFoundException, a try-catch would handle it.
            return NotFound(new PathUnknownErrorMessageResponse { Code = NotFoundErrorCode.StoreIdNotFound, Message = $"Store with ID '{storeId}' not found for deletion." });
        }
        return NoContent(); // 204
    }
    ```
*   **Example HTTP Request:**
    `DELETE /stores/01GKNSYMQ4KX71S0N0Z250BZ5X` (an existing ID)
*   **Example HTTP Response (204 No Content):**
    `Status: 204 No Content`
    (No response body)
*   **ProducesResponseType attribute:**
    `[ProducesResponseType(StatusCodes.Status204NoContent)]`

### Step 5: Handle Store Not Found During Delete (404)
*   **Goal:** If store not found, return 404.
*   **Controller Code:** (Shown in Step 4 `if (!deleted)`)
*   **Example HTTP Request:**
    `DELETE /stores/non-existent-id-for-delete`
*   **Example HTTP Response (404 Not Found):**
    ```json
    {
        "code": "store_id_not_found",
        "message": "Store with ID 'non-existent-id-for-delete' not found for deletion."
    }
    ```
*   **ProducesResponseType attribute:**
    `[ProducesResponseType(typeof(PathUnknownErrorMessageResponse), StatusCodes.Status404NotFound)]`

### Step 6 to 11: Validation and Error Responses (400, 401, 403, 409, 422, 500)
*   **Validation for `store_id` (Step 6):** Similar to `GET /stores/{store_id}` Step 7. Payload would be an invalid `store_id` in the URL, e.g., `DELETE /stores/!@#$`, resulting in a 400 with `ValidationErrorMessageResponse`.
*   **Error Payloads (Steps 7-11):** Structurally identical to those in `GET /stores` and `GET /stores/{store_id}` for the respective error codes. Triggers are auth failure, permission denial, or service throwing specific exceptions during `_storeService.DeleteStoreAsync(storeId)`.
*   Ensure corresponding `ProducesResponseType` attributes are added for each.

### Step 12: Verify Idempotency of Delete
*   **Goal:** Test idempotency.
*   **Example Test Scenario "Payloads":**
    1.  **Request 1 (Delete existing):**
        `DELETE /stores/01GKNT00ABCD1S0N0Z250CDEFG`
        **Response 1:** `204 No Content`
    2.  **Request 2 (Delete same, now non-existent):**
        `DELETE /stores/01GKNT00ABCD1S0N0Z250CDEFG`
        **Response 2:** `404 Not Found` (with `PathUnknownErrorMessageResponse` body)
    3.  **Request 3 (Delete initially non-existent):**
        `DELETE /stores/id-that-never-existed`
        **Response 3:** `404 Not Found`

### Step 13: Clarify "does not delete the data associated"
*   **This is a service-layer concern.** The "payload" here is the behavior of `_storeService.DeleteStoreAsync`. It should only mark the store as deleted or remove its primary record, not cascade delete related authorization models or tuples.
*   **Test (Conceptual):**
    1. Create store, add auth model, add tuples.
    2. DELETE the store.
    3. Attempt to read the auth model (e.g., via an endpoint if it exists for a "deleted" store's models, or directly query DB). The data should still be there.

### Step 14-19: Advanced Tests (Logging, Case Sensitivity, Dependencies, Long IDs, Response Body on 204, Empty ID)
*   These steps involve specific test scenarios.
    *   **Logging:** Example log: `INFO: Store '01GKNSYMQ4KX71S0N0Z250BZ5X' deleted successfully.` or `WARN: Attempt to delete non-existent store 'blah'.`
    *   **Response Body on 204 (Step 18):** Verify `Content-Length: 0` or no body in HTTP trace.

### Step 20: Add XML Documentation Comments
*   **Goal:** Add /// XML comments.
*   **Example "Payload" (C# Code Snippet):**
    ```csharp
    /// <summary>
    /// Delete a store.
    /// </summary>
    /// <remarks>
    /// Delete an OpenFGA store. This does not delete the data associated with the store, like tuples or authorization models.
    /// </remarks>
    /// <param name="storeId">The identifier of the store to delete.</param>
    /// <response code="204">A successful response, indicating the store was deleted (or was already not present).</response>
    /// <response code="400">Request failed due to invalid input (e.g., invalid store_id format).</response>
    /// <response code="404">Store not found.</response>
    // ... other response codes documented ...
    [HttpDelete("/stores/{storeId}")]
    // ... attributes ...
    public async Task<IActionResult> DeleteStore([FromRoute] string storeId) {/*...*/}
    ```

This level of detail for all 17 endpoints would be exceptionally long. The pattern, however, should be clear. For subsequent endpoints, I can summarize the types of payloads for brevity unless you need a specific one expanded.