Codezerg.OpenRouter

using Codezerg.OpenRouter;
using Codezerg.OpenRouter.Models;

var config = new OpenRouterClientOptions
{
    ApiKey = Environment.GetEnvironmentVariable("OPENROUTER_API_KEY"),
    DefaultModel = "deepseek/deepseek-chat-v3.1:free",
    UserAgent = "myapp/1.0",                  // required by OpenRouter
    Referer = "https://github.com/myuser/app" // required by OpenRouter
};

using var client = new OpenRouterClient(config);

var req = new ChatRequest {
    Messages = new() {
        ChatMessage.System("You are a helpful assistant."),
        ChatMessage.User("What is the capital of France?")
    }
};

var resp = await client.SendChatCompletionAsync(req);

Console.WriteLine(resp.Choices[0].Message?.FirstTextContent);
// => "The capital of France is Paris."

var req = new ChatRequest {
    Messages = new() {
        ChatMessage.User("Write a short poem about a sunrise.")
    }
};

await foreach (var chunk in client.StreamChatCompletionAsync(req))
{
    var token = chunk.Choices?[0].Delta?.Content;
    if (!string.IsNullOrEmpty(token))
        Console.Write(token);
}

var message = new ChatMessage(ChatRole.User)
    .AddText("Describe this picture")
    .AddImage("https://upload.wikimedia.org/wikipedia/commons/3/3a/Cat03.jpg");

var resp = await client.SendChatCompletionAsync(new ChatRequest {
    Messages = new() { message }
});
Console.WriteLine(resp.Choices[0].Message?.FirstTextContent);

var req = new ChatRequest {
    Messages = new() { ChatMessage.User("What's the weather in Paris?") },
    Tools = new() {
        new ToolDefinition {
            Function = new FunctionDescription {
                Name = "get_weather",
                Description = "Gets weather",
                Parameters = JObject.Parse("{\"type\":\"object\",\"properties\":{\"city\":{\"type\":\"string\"}}}")
            }
        }
    }
};

var resp = await client.SendChatCompletionAsync(req);

if (resp.Choices[0].Message?.ToolCalls?.Count > 0) {
    var call = resp.Choices[0].Message.ToolCalls[0];
    Console.WriteLine($"{call.Function.Name}({call.Function.Arguments})");
}

var credits = await client.GetCreditsAsync();
Console.WriteLine($"Credits: {credits.TotalCredits}, Used: {credits.TotalUsage}");

var activity = await client.GetActivityAsync();
foreach (var day in activity)
    Console.WriteLine($"{day.Date}: {day.Model} - {day.Requests} requests");

var models = await client.GetModelsAsync();
foreach (var m in models)
    Console.WriteLine($"{m.Name} ({m.Id})");

var config = new OpenRouterClientOptions()
    .WithApiKey("your-api-key")
    .WithDefaultModel("meta-llama/llama-3.2-3b-instruct:free")
    .WithUserAgent("myapp/1.0")
    .WithReferer("https://yourapp.com")
    .WithTimeout(TimeSpan.FromSeconds(60));