Streaming & Events

Svantic supports real-time streaming via the A2A protocol’s SSE (Server-Sent Events) mechanism, enabling clients to receive progressive updates as tasks execute.

A2A Streaming

When a client sends a task to Svantic via message/stream, the response is an SSE stream of A2A events:

Event Types

TaskStatusUpdateEvent

Reports task lifecycle changes:

State	Meaning
`submitted`	Task received, queued for processing
`working`	Execution in progress
`input-required`	Waiting for user input (form, approval)
`completed`	Task finished successfully
`failed`	Task failed with error
`canceled`	Task was canceled

Message

An agent response containing one or more Parts:

Part Kind	Content
`TextPart`	Plain text (thoughts, explanations, answers)
`DataPart`	Structured JSON (tool results, forms, capability invocations)
`FilePart`	File content or reference

TaskArtifactUpdateEvent

Emitted when the agent produces a tangible output — a file, a structured document, or a final result.

Consuming Streams

Using RemoteAgent (SDK)

import { RemoteAgent } from '@svantic/sdk';

const remote = await RemoteAgent.connect('http://savant:3000');
const stream = remote.send_stream('Analyze this codebase', 'session-1');

for await (const event of stream) {
    if (event.kind === 'status-update') {
        console.log('Status:', event.status.state);
    }
    if (event.kind === 'message') {
        for (const part of event.message.parts) {
            if (part.kind === 'text') {
                process.stdout.write(part.text);
            }
        }
    }
}

Using the REST API

For direct HTTP access, use POST /send with method: "message/stream" — see the Using the API guide.

Event Conversion

Svantic’s internal engine events are automatically converted to A2A events by the EventConverter:

Internal Event	A2A Event
Agent text output	`Message` with `TextPart`
Tool call start	`TaskStatusUpdateEvent` (working)
Tool result	`Message` with `DataPart`
Plan approval request	`Message` with `DataPart` (form)
A2UI form	`Message` with `DataPart` (form fields)
Execution complete	`TaskStatusUpdateEvent` (completed)
Error	`TaskStatusUpdateEvent` (failed)

​Streaming & Events

​A2A Streaming

​Event Types

​TaskStatusUpdateEvent

​Message

​TaskArtifactUpdateEvent

​Consuming Streams

​Using RemoteAgent (SDK)

​Using the REST API

​Event Conversion