Structured Output (JSON)

[EdCharbeneau]

It would be nice to see some examples of Structured Output (JSON) data with Ollama, or other local models.

[VitaliyMF]

You can get structured output in a this way (with the latest Microsoft.Extensions.AI.Ollama):

var chatClient = new OllamaChatClient("http://localhost:11434/", modelId: "gemma2" );
var myResponseJsonSchema = JsonDocument.Parse(jsonSchemaStr).RootElement;
var chatOptions = new ChatOptions {
	ResponseFormat = new ChatResponseFormatJson(myResponseJsonSchema ),
};
// assuming your input prompt is "chatMessages"
var chatResponse = await chatClient.GetResponseAsync(chatMessages, chatOptions);
var responseJsonStr = chatResponse.Message.Text;
var responseModel = JsonSerializer.Deserialize<SomeModelClass>(responseJsonStr);

[TsuyoshiUshio]

For me, useNativeJsonSchema works for 4o model.

var response = await _context.ChatClient.GetResponseAsync<ModifyQueryResult>(localHistory, options, useNativeJsonSchema: true);

[JamesFieldist]

I would suggest that ChatResponseFormatJson should have a few more overrides. One should be a generic that just takes the type and does all of the work for you with System.Text.Json, another take a type and do the same. The way it is now is way too complex for what should be trivial.

Also there are no samples for this so it's guessing in the dark and this stuff keeps changing.