AG-UI

The AG-UI protocol is an open standard for streaming agent events to frontend clients. It defines a structured event sequence — run lifecycle, text deltas, tool calls, reasoning content — so any AG-UI-compatible frontend can consume agent output without custom integration code. This SDK emits every Stream call as a properly sequenced AG-UI event stream. Events like RUN_STARTED, TEXT_MESSAGE_CONTENT, TOOL_CALL_START, and REASONING_MESSAGE_CONTENT are produced in the correct order during every Stream call. Any frontend built on the AG-UI client SDK — including CopilotKit and custom React clients — works out of the box. Serialize any event with event.ToJSON() and forward it over SSE, WebSocket, or Redis to your frontend. The receiving client handles rendering, tool display, and state — your Go server just forwards bytes.

Basic integration

When using conversation, pass the session ID in AgentStreamOptions — the AG-UI client uses it to thread messages correctly across turns:

opts := &agent.AgentStreamOptions{
    ConversationOptions: &agent.ConversationOptions{ID: sessionID},
}
agentStream, err := a.Stream(ctx, prompt, opts)
if err != nil {
    return err
}
runID := agentStream.ID()
_ = runID // the RUN_STARTED event also carries runID via its RunID field
eventCh, err := agentStream.Events(ctx)

Enable streaming, then forward serialized events to your frontend over SSE, WebSocket, or Redis:

a, err := agent.NewAgent(
    agent.WithLLMClient(llmClient),
)

agentStream, err := a.Stream(ctx, prompt, nil)
if err != nil {
    return err
}
runID := agentStream.ID()
_ = runID
eventCh, err := agentStream.Events(ctx)
if err != nil {
    return err
}

for ev := range eventCh {
    if ev == nil {
        continue
    }
    jsonBytes, err := ev.ToJSON()
    if err != nil {
        continue
    }
    // Forward jsonBytes to SSE/WebSocket client
    _ = jsonBytes
}

Call event.ToJSON() on any AgentEvent to get AG-UI-compatible JSON.

Reference app

Agent Chat — production-shaped split API/worker app with Postgres, SSE streaming, and CopilotKit UI.

Example

Go SSE server + CopilotKit UI

Streaming

Stream API and event types

Approvals

CUSTOM events and AgentStream.Approve

Overview

Getting Started

Runtimes

Features

Advanced

Observability

Testing & Evaluation

Production

Reference Apps

AG-UI

Basic integration

Reference app

Example

AG-UI

Streaming

Approvals

​Basic integration

​Reference app

​Example

AG-UI

​Related

Streaming

Approvals

Basic integration

Reference app

Example

Related