Add demo for structured outputs

demo/Demos/StructuredOutputConsole.cs

@@ -0,0 +1,242 @@
+using System.Text.Json;
+using System.Text.Json.Schema;
+using System.Text.Json.Serialization;
+using OllamaSharp;
+using OllamaSharp.Models.Chat;
+using Spectre.Console;
+
+namespace OllamaApiConsole.Demos;
+
+/// <summary>
+/// Demonstrates structured outputs by extracting a recipe in a strongly-typed JSON schema.
+/// The user types a dish name and the model returns structured data that is rendered as a formatted table.
+/// </summary>
+public class StructuredOutputConsole(IOllamaApiClient ollama) : OllamaConsole(ollama)
+{
+	private static readonly JsonSerializerOptions SERIALIZER_OPTIONS = new()
+	{
+		PropertyNameCaseInsensitive = true,
+		DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull
+	};
+
+	/// <inheritdoc/>
+	public override async Task Run()
+	{
+		AnsiConsole.Write(new Rule("Structured outputs").LeftJustified());
+		AnsiConsole.WriteLine();
+		AnsiConsole.MarkupLine("This demo asks the model to return data that exactly matches a predefined JSON schema.");
+		AnsiConsole.MarkupLine($"Type the name of any dish and get back a structured [{AccentTextColor}]recipe[/] — no free-form text, only typed data.");
+		AnsiConsole.WriteLine();
+
+		Ollama.SelectedModel = await SelectModel("Select a model you want to use:");
+		SetThink(new ThinkValue(false));
+
+		if (string.IsNullOrEmpty(Ollama.SelectedModel))
+			return;
+
+		var schema = JsonSerializerOptions.Default.GetJsonSchemaAsNode(typeof(RecipeSchema));
+
+		AnsiConsole.Write(new Rule($"[{HintTextColor}]Expected JSON schema[/]").LeftJustified());
+		AnsiConsole.WriteLine();
+		AnsiConsole.MarkupLineInterpolated($"[{HintTextColor}]{Markup.Escape(JsonSerializer.Serialize(schema, new JsonSerializerOptions { WriteIndented = true }))}[/]");
+		AnsiConsole.WriteLine();
+
+		WriteChatInstructionHint();
+
+		var keepChatting = true;
+
+		do
+		{
+			AnsiConsole.WriteLine();
+			AnsiConsole.MarkupLineInterpolated($"You are talking to [{AccentTextColor}]{Ollama.SelectedModel}[/] now.");
+
+			string message;
+
+			do
+			{
+				AnsiConsole.WriteLine();
+				message = ReadInput($"Enter a [{AccentTextColor}]dish name[/] [{HintTextColor}](e.g. \"Pasta Carbonara\" or \"Vegan Chocolate Cake\")[/]");
+
+				if (string.IsNullOrWhiteSpace(message))
+					continue;
+
+				if (message.Equals(EXIT_COMMAND, StringComparison.OrdinalIgnoreCase))
+				{
+					keepChatting = false;
+					break;
+				}
+
+				if (message.Equals(TOGGLETHINK_COMMAND, StringComparison.OrdinalIgnoreCase))
+				{
+					ToggleThink();
+					keepChatting = true;
+					continue;
+				}
+
+				if (message.Equals(START_NEW_COMMAND, StringComparison.OrdinalIgnoreCase))
+				{
+					keepChatting = true;
+					break;
+				}
+
+				var prompt = $"Create a detailed recipe for: {message}. Respond only with the JSON object, no markdown, no explanation.";
+				var json = new System.Text.StringBuilder();
+
+				// Step 1: stream the raw model output live
+				AnsiConsole.Write(new Rule($"[{HintTextColor}]Raw model output[/]").LeftJustified());
+				AnsiConsole.WriteLine();
+				AnsiConsole.WriteLine();
+
+				var chat = new Chat(Ollama) { Think = Think };
+				chat.OnThink += (sender, thoughts) => AnsiConsole.MarkupInterpolated($"[{AiThinkTextColor}]{thoughts}[/]");
+
+				await foreach (var token in chat.SendAsync(prompt, tools: null, format: schema))
+				{
+					AnsiConsole.MarkupInterpolated($"[{HintTextColor}]{Markup.Escape(token)}[/]");
+					json.Append(token);
+				}
+
+				AnsiConsole.WriteLine();
+				AnsiConsole.WriteLine();
+
+				// Step 2: pretty-print the JSON
+				AnsiConsole.Write(new Rule($"[{HintTextColor}]Parsed JSON[/]").LeftJustified());
+				AnsiConsole.WriteLine();
+				RenderPrettyJson(json.ToString());
+				AnsiConsole.WriteLine();
+
+				// Step 3: the final recipe card
+				AnsiConsole.Write(new Rule($"[{HintTextColor}]Recipe[/]").LeftJustified());
+				AnsiConsole.WriteLine();
+				RenderRecipe(json.ToString(), message);
+			}
+			while (!string.IsNullOrEmpty(message));
+		}
+		while (keepChatting);
+	}
+
+	private static void RenderPrettyJson(string json)
+	{
+		try
+		{
+			using var doc = JsonDocument.Parse(json);
+			var pretty = JsonSerializer.Serialize(doc, new JsonSerializerOptions { WriteIndented = true });
+			AnsiConsole.MarkupLineInterpolated($"[{AiTextColor}]{Markup.Escape(pretty)}[/]");
+		}
+		catch (JsonException)
+		{
+			// Not yet valid JSON — just print as-is
+			AnsiConsole.MarkupLineInterpolated($"[{HintTextColor}]{Markup.Escape(json)}[/]");
+		}
+	}
+
+	private static void RenderRecipe(string json, string userInput)
+	{
+		RecipeSchema? recipe = null;
+
+		try
+		{
+			recipe = JsonSerializer.Deserialize<RecipeSchema>(json, SERIALIZER_OPTIONS);
+		}
+		catch (JsonException)
+		{
+			AnsiConsole.MarkupLineInterpolated($"[{ErrorTextColor}]Could not parse the model's response as a recipe. Raw output:[/]");
+			AnsiConsole.WriteLine(json);
+			return;
+		}
+
+		if (recipe is null)
+		{
+			AnsiConsole.MarkupLineInterpolated($"[{WarningTextColor}]The model returned an empty response.[/]");
+			return;
+		}
+
+		AnsiConsole.MarkupLineInterpolated($"[bold {AccentTextColor}]{Markup.Escape(recipe.Name ?? userInput)}[/]");
+
+		if (!string.IsNullOrWhiteSpace(recipe.Description))
+			AnsiConsole.MarkupLineInterpolated($"[italic]{Markup.Escape(recipe.Description)}[/]");
+
+		AnsiConsole.WriteLine();
+
+		// Meta row: timing, servings, difficulty
+		var metaTable = new Table().NoBorder().HideHeaders();
+		metaTable.AddColumn(new TableColumn("").Width(22));
+		metaTable.AddColumn(new TableColumn(""));
+
+		if (recipe.PrepTimeMinutes > 0)
+			metaTable.AddRow($"[{HintTextColor}]Prep time[/]", $"{recipe.PrepTimeMinutes} min");
+
+		if (recipe.CookTimeMinutes > 0)
+			metaTable.AddRow($"[{HintTextColor}]Cook time[/]", $"{recipe.CookTimeMinutes} min");
+
+		if (recipe.PrepTimeMinutes > 0 && recipe.CookTimeMinutes > 0)
+			metaTable.AddRow($"[{HintTextColor}]Total time[/]", $"{recipe.PrepTimeMinutes + recipe.CookTimeMinutes} min");
+
+		if (recipe.Servings > 0)
+			metaTable.AddRow($"[{HintTextColor}]Servings[/]", $"{recipe.Servings}");
+
+		if (!string.IsNullOrWhiteSpace(recipe.Difficulty))
+			metaTable.AddRow($"[{HintTextColor}]Difficulty[/]", recipe.Difficulty);
+
+		AnsiConsole.Write(metaTable);
+		AnsiConsole.WriteLine();
+
+		// Ingredients
+		if (recipe.Ingredients?.Length > 0)
+		{
+			AnsiConsole.MarkupLine($"[bold]Ingredients[/]");
+			foreach (var ingredient in recipe.Ingredients)
+				AnsiConsole.MarkupLineInterpolated($"  [{AiTextColor}]•[/] {Markup.Escape(ingredient)}");
+
+			AnsiConsole.WriteLine();
+		}
+
+		// Steps
+		if (recipe.Steps?.Length > 0)
+		{
+			AnsiConsole.MarkupLine($"[bold]Steps[/]");
+			for (var i = 0; i < recipe.Steps.Length; i++)
+				AnsiConsole.MarkupLineInterpolated($"  [{AiTextColor}]{i + 1,2}.[/] {Markup.Escape(recipe.Steps[i])}");
+
+			AnsiConsole.WriteLine();
+		}
+	}
+
+	/// <summary>
+	/// Defines the JSON schema the model must respond with.
+	/// </summary>
+	private sealed class RecipeSchema
+	{
+		/// <summary>The official name of the dish.</summary>
+		[JsonPropertyName("name")]
+		public string? Name { get; set; }
+
+		/// <summary>A short, appetising description of the dish.</summary>
+		[JsonPropertyName("description")]
+		public string? Description { get; set; }
+
+		/// <summary>List of ingredients with quantities.</summary>
+		[JsonPropertyName("ingredients")]
+		public string[]? Ingredients { get; set; }
+
+		/// <summary>Ordered list of preparation steps.</summary>
+		[JsonPropertyName("steps")]
+		public string[]? Steps { get; set; }
+
+		/// <summary>Preparation time in minutes, before any cooking starts.</summary>
+		[JsonPropertyName("prepTimeMinutes")]
+		public int PrepTimeMinutes { get; set; }
+
+		/// <summary>Cooking or baking time in minutes.</summary>
+		[JsonPropertyName("cookTimeMinutes")]
+		public int CookTimeMinutes { get; set; }
+
+		/// <summary>Number of portions the recipe yields.</summary>
+		[JsonPropertyName("servings")]
+		public int Servings { get; set; }
+
+		/// <summary>Subjective difficulty, e.g. "Easy", "Medium", "Hard".</summary>
+		[JsonPropertyName("difficulty")]
+		public string? Difficulty { get; set; }
+	}
+}

demo/OllamaConsole.cs

@@ -144,7 +144,15 @@ protected void WriteChatInstructionHint()
 	internal void ToggleThink()
 	{
 		// null -> false -> true -> null -> ...
-		Think = Think == null ? false : ((bool?)Think == false ? true : ((bool?)Think == true ? null : false));
+		SetThink(Think == null ? false : ((bool?)Think == false ? true : ((bool?)Think == true ? null : false)));
+	}
+
+	/// <summary>
+	/// Toggles the think mode between null, false, and true.
+	/// </summary>
+	internal void SetThink(object? value)
+	{
+		Think = new ThinkValue(value);
 		AnsiConsole.MarkupLine($"[{HintTextColor}]Think mode is [{AccentTextColor}]{Think?.ToString()?.ToLower() ?? "(null)"}[/].[/]");
 	}
 

demo/Program.cs

@@ -55,7 +55,7 @@
 				new SelectionPrompt<string>()
 					.PageSize(10)
 					.Title("What demo do you want to run?")
-					.AddChoices("Chat", "Image chat", "Image generation (experimental)", "Tool chat", "Tool chat (Microsoft.Extensions.AI)", "Model manager", "Exit"));
+					.AddChoices("Chat", "Image chat", "Image generation (experimental)", "Tool chat", "Tool chat (Microsoft.Extensions.AI)", "Structured outputs", "Model manager", "Exit"));
 
 	AnsiConsole.Clear();
 
@@ -83,6 +83,10 @@
 				await new ExtensionsAiToolConsole(ollama!).Run();
 				break;
 
+			case "Structured outputs":
+				await new StructuredOutputConsole(ollama!).Run();
+				break;
+
 			case "Model manager":
 				await new ModelManagerConsole(ollama!).Run();
 				break;