Microsoft Agent Framework — Foundations

[Description("Get the weather for a given location.")]
static string GetWeather(
    [Description("The location to get the weather for.")] string location) =>
    $"The weather in {location} is cloudy with a high of 15°C.";

AIAgent weatherAgent = client
    .GetChatClient(deploymentName)
    .AsAIAgent(
        instructions: "You are a helpful weather assistant.",
        name: "WeatherAgent",
        description: "An agent that answers weather questions.",
        tools: [AIFunctionFactory.Create(GetWeather)]
    );

Console.WriteLine(await weatherAgent.RunAsync("What is the weather like in Amsterdam?"));

AgentSession session = await agent.CreateSessionAsync();

await agent.RunAsync("My name is Alice", session);

// Serialize session to JSON
var serialized = await agent.SerializeSessionAsync(session);
Console.WriteLine($"Session serialized ({serialized.GetRawText().Length} bytes)");

// Store anywhere — database, file, Redis, blob storage

// Restore session from serialized data
var restoredSession = await agent.DeserializeSessionAsync(serialized);

// Agent remembers everything from the original session
await agent.RunAsync("Do you still remember my name?", restoredSession);
// → "Yes, your name is Alice!"

sealed class FileChatHistoryProvider(string filePath) : ChatHistoryProvider
{
    protected override ValueTask<IEnumerable<ChatMessage>> ProvideChatHistoryAsync(
        InvokingContext context, CancellationToken cancellationToken = default)
    {
        if (!File.Exists(filePath))
            return new(Enumerable.Empty<ChatMessage>());

        var json = File.ReadAllText(filePath);
        var messages = JsonSerializer.Deserialize(json, ChatHistoryJsonContext.Default.ListChatMessage) ?? [];
        return new(messages.AsEnumerable());
    }

    protected override ValueTask StoreChatHistoryAsync(InvokedContext context, CancellationToken cancellationToken = default)
    {
        List<ChatMessage> existing = [];
        if (File.Exists(filePath))
        {
            var json = File.ReadAllText(filePath);
            existing = JsonSerializer.Deserialize(json, ChatHistoryJsonContext.Default.ListChatMessage) ?? [];
        }

        existing.AddRange(context.RequestMessages);
        existing.AddRange(context.ResponseMessages ?? []);

        File.WriteAllText(path: filePath, JsonSerializer.Serialize(existing, ChatHistoryJsonContext.Default.ListChatMessage));
        return default;
    }
}

AIAgent agent = new AzureOpenAIClient(new Uri(endpoint!), new DefaultAzureCredential())
    .GetChatClient(deploymentName)
    .AsAIAgent(new ChatClientAgentOptions
    {
        Name = "PersistentAgent",
        ChatOptions = new ChatOptions
        {
            Instructions = "You are a friendly assistant. Keep your answers brief.",
        },
        ChatHistoryProvider = new FileChatHistoryProvider(filePath),
    });

sealed class FileChatHistoryProvider : ChatHistoryProvider
{
    private readonly string _directory;
    private readonly ProviderSessionState<SessionState> _sessionState;

    public FileChatHistoryProvider(string directory, string? existingSessionId = null)
    {
        _directory = directory;
        _sessionState = new ProviderSessionState<SessionState>(
            _ => new SessionState(existingSessionId ?? Guid.NewGuid().ToString("N")[..8]),
            nameof(FileChatHistoryProvider));
    }

    public string GetSessionId(AgentSession? session) =>
        _sessionState.GetOrInitializeState(session).SessionId;

    protected override ValueTask<IEnumerable<ChatMessage>> ProvideChatHistoryAsync(
        InvokingContext context, CancellationToken cancellationToken = default)
    {
        var state = _sessionState.GetOrInitializeState(context.Session);
        var path = Path.Combine(_directory, $"{state.SessionId}.json");
        // ... read from session-specific file
    }

    // ... StoreChatHistoryAsync implementation similar to before, but using session-specific file

    sealed class SessionState(string sessionId)
    {
        public string SessionId { get; } = sessionId;
    }
}

var sessionId = historyProvider.GetSessionId(session);
var restoredProvider = new FileChatHistoryProvider(historyDir, sessionId);

AIAgent agent2 = client.GetChatClient(deploymentName)
    .AsAIAgent(new ChatClientAgentOptions
    {
        ChatHistoryProvider = restoredProvider,
    });

AgentSession session2 = await agent2.CreateSessionAsync();
await agent2.RunAsync("Do you remember my name?", session2); // → "Alice"