Add a prompt that summarises what a movie's reviews say

.agents/skills/expose-a-use-case/SKILL.md

@@ -29,7 +29,7 @@ The SDK finds every class in the assembly (`WithToolsFromAssembly`, `WithResourc
 4. Write the method with `sender` and `cancellationToken` first, then required inputs, then optional ones with defaults.
 5. Document it: `<summary>` saying what it does, what it returns and which tool to call first; a `<param>` for every input except `sender` and the token, with allowed values and where to find ids. Put the XML comment above the attributes.
 6. Return a result model from `src/Presentation/Models/` (records with `[property: Description]`, because the output schema reads attributes), mapped in `ResultMapper`. Add new models to `AppJsonSerializerContext` (`json-serialization`).
-7. Build a prompt's messages with `PromptContent`, and embed the movie or author it's about when you can find one. A prompt argument that names a movie or author gets suggestions from `Completions/CompletionHandler.cs`; add its name there. So does the id in a resource template, which suggests ids by their first characters or the title or name they belong to.
+7. Build a prompt's messages with `PromptContent`, and embed the movie or author it's about when you can find one. A prompt argument that names a movie or author gets suggestions from `Completions/CompletionHandler.cs`; add its name there. So does a prompt's `movieId`, and the id in a resource template, which suggest ids by their first characters or the title or name they belong to.
 8. Update the server instructions in `WebApplicationBuilderExtensions` if the model needs to know the new thing exists (`api-conventions`).
 9. Test it twice: a unit test calling the static method with a faked `ISender` (`tests/Presentation.Tests.Unit/Tools/`), and an integration test through the MCP client (`presentation-integration-tests`). Add a tool to the list in `ToolListTests`.
 

src/Presentation/Completions/CompletionHandler.cs

@@ -52,6 +52,9 @@ private static async Task<CompleteResult> CompletePromptArgument(ISender sender,
                 return Result([.. page.Items.Select(m => m.Title)], page.TotalCount);
             }
 
+            case "movieId":
+                return await CompleteResourceId(sender, argument, cancellationToken);
+
             case "authorName":
             {
                 var page = await sender.Send(new AuthorQueries.GetAuthors.GetAuthorsQuery

src/Presentation/Prompts/MoviePrompts.cs

@@ -95,6 +95,29 @@ public static partial GetPromptResult ReviewMovie(
         };
     }
 
+    /// <summary>Summarise what reviewers actually said about a movie: the themes they agree on, where they disagree, and whether their words match their stars.</summary>
+    /// <param name="movieId">The movie's id (a GUID). Start typing its title or id for suggestions.</param>
+    [McpServerPrompt(Name = "summarise_movie_reviews", Title = "Summarise a movie's reviews", IconSource = ItemIcons.Review)]
+    public static async partial Task<GetPromptResult> SummariseMovieReviews(
+        ISender sender,
+        Guid movieId,
+        CancellationToken cancellationToken)
+    {
+        var movie = (await sender.Send(new Queries.GetMovieById.GetMovieByIdQuery { Id = movieId }, cancellationToken))
+            .ToResult(includeReviews: true);
+
+        return new GetPromptResult
+        {
+            Description = $"Summarise the reviews of {movie.Title}",
+            Messages =
+            [
+                PromptContent.Text($"Summarise what reviewers said about \"{movie.Title}\", using the movie below. Give the themes they " +
+                    "agree on, where they disagree, and whether their words match their stars."),
+                PromptContent.Embed($"movies://{movie.Id}", McpSerializer.Serialize(movie))
+            ]
+        };
+    }
+
     private static async Task<MovieResult?> FindMovie(ISender sender, string? title, CancellationToken cancellationToken)
     {
         var page = await sender.Send(new Queries.GetMovies.GetMoviesQuery

tests/Presentation.Tests.Integration/Completions/CompletionTests.cs

@@ -101,6 +101,19 @@ public async Task CompleteReviewId_WithEmptyValue_ShouldCap_AtTheProtocolLimit()
         result.Completion.HasMore.ShouldBe(true);
     }
 
+    [Fact]
+    public async Task CompleteMovieId_OnMovieReviewsPrompt_ShouldReturn_Ids()
+    {
+        // Arrange
+        var movie = (await this.CallAsync<ResultPage<MovieResult>>("movies_search")).Items[0];
+
+        // Act
+        var result = await this.Client.CompleteAsync(new PromptReference { Name = "summarise_movie_reviews" }, "movieId", movie.Title);
+
+        // Assert
+        result.Completion.Values.ShouldContain(movie.Id.ToString());
+    }
+
     [Fact]
     public async Task CompleteMovieId_ShouldMatch_Title()
     {

tests/Presentation.Tests.Integration/Prompts/PromptTests.cs

@@ -16,7 +16,7 @@ public async Task ListPrompts_ShouldReturn_EveryPrompt()
         var prompts = await this.Client.ListPromptsAsync();
 
         // Assert
-        prompts.Select(p => p.Name).ShouldBe(["summarise_movie_reception", "compare_movies", "review_movie", "summarise_author_reviews"], ignoreOrder: true);
+        prompts.Select(p => p.Name).ShouldBe(["summarise_movie_reception", "compare_movies", "review_movie", "summarise_author_reviews", "summarise_movie_reviews"], ignoreOrder: true);
 
         foreach (var prompt in prompts)
         {
@@ -27,6 +27,33 @@ public async Task ListPrompts_ShouldReturn_EveryPrompt()
         }
     }
 
+    [Fact]
+    public async Task SummariseMovieReviews_ShouldEmbed_Movie()
+    {
+        // Arrange
+        var movie = await this.FirstMovieAsync();
+
+        // Act
+        var result = await this.Client.GetPromptAsync("summarise_movie_reviews",
+            new Dictionary<string, object?> { ["movieId"] = movie.Id });
+
+        // Assert
+        result.Messages.Count.ShouldBe(2);
+        result.Messages[0].Content.ShouldBeOfType<TextContentBlock>().Text.ShouldContain(movie.Title);
+        ShouldEmbed(result.Messages[1], movie);
+    }
+
+    [Fact]
+    public async Task SummariseMovieReviews_WithUnknownId_ShouldThrow()
+    {
+        // Act
+        var exception = await Should.ThrowAsync<McpProtocolException>(() => this.Client.GetPromptAsync("summarise_movie_reviews",
+            new Dictionary<string, object?> { ["movieId"] = Guid.NewGuid() }).AsTask());
+
+        // Assert
+        exception.Message.ShouldNotBeNullOrWhiteSpace();
+    }
+
     [Fact]
     public async Task SummariseAuthorReviews_ShouldEmbed_Author()
     {