Microsoft Agent Framework used to carry its own copy of the AG-UI protocol (events, messages, tools, interrupts, state, multimodal, SSE and protobuf transports). That protocol is now maintained once, in the AG-UI C# SDK, and stays wire compatible with the TypeScript and Python SDKs. MAF no longer tracks protocol changes in a second implementation and keeps only the ASP.NET hosting glue that is genuinely framework specific.

The programming model is unchanged: the SDK is built on Microsoft.Extensions.AI, so IChatClient remains the single integration point on both the client and the server.

The ASP.NET hosting integration stays in this repository as Microsoft.Agents.AI.Hosting.AGUI.AspNetCore, now layered over the AGUI.Server primitives.

Source of the SDK packages: ag-ui-protocol/ag-ui (see PR #1963).

Drop the reference to Microsoft.Agents.AI.AGUI and add the AGUI.* packages you actually use (AGUI.Client for clients, AGUI.Server plus AGUI.Abstractions for server and hosting, plus AGUI.Protobuf if you opt into the protobuf transport).

The two hosting methods were renamed to match the sibling AddA2AServer convention. The old names are gone.

// Before
builder.Services.AddAGUI();
app.MapAGUI("/", agent);

// After
builder.Services.AddAGUIServer();
app.MapAGUIServer("/", agent);

The single Microsoft.Agents.AI.AGUI namespace splits along the SDK package boundaries: AGUI.Client, AGUI.Server, and AGUI.Abstractions.

The positional constructor becomes options based.

// Before
using Microsoft.Agents.AI.AGUI;
var chatClient = new AGUIChatClient(
    httpClient,
    serverUrl,
    jsonSerializerOptions: AGUIClientSerializerContext.Default.Options);

// After
using AGUI.Client;
var chatClient = new AGUIChatClient(new(httpClient, serverUrl)
{
    JsonSerializerOptions = AGUIClientSerializerContext.Default.Options,
});

Read it back from ChatOptions via the SDK extension.

using AGUI.Abstractions;
using AGUI.Server;

if (!chatOptions.TryGetRunAgentInput(out RunAgentInput? agentInput))
{
    // not an AG-UI-originated request
}

Working end to end samples that use the external packages live under:

• samples/02-agents/AGUI
• samples/05-end-to-end/AGUIClientServer
• samples/05-end-to-end/AGUIWebChat