Stream Events

GET

tasks

{task_id}

stream

Stream Task Events by ID

curl --request GET \
  --url https://api.example.com/tasks/{task_id}/stream

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.example.com/tasks/{task_id}/stream",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "GET",
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"net/http"
	"io"
)

func main() {

	url := "https://api.example.com/tasks/{task_id}/stream"

	req, _ := http.NewRequest("GET", url, nil)

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

require 'uri'
require 'net/http'

url = URI("https://api.example.com/tasks/{task_id}/stream")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Get.new(url)

response = http.request(request)
puts response.read_body

{
  "type": "start"
}

{
  "detail": [
    {
      "loc": [
        "<string>"
      ],
      "msg": "<string>",
      "type": "<string>"
    }
  ]
}

SSE Behavior:

Supports automatic reconnection with Last-Event-ID header
When the client reconnects, the server resumes from the last received event
Stream terminates with [DONE] message

Stream Event Types

The stream returns TextStreamPartWrapper events with a discriminated type field. These events are compatible with the Vercel AI SDK format.

Event Type	Description
`start`	Marks the beginning of the streaming session
`start-step`	Marks the beginning of an agentic step
`text-start`	Marks the beginning of a text block
`text-delta`	Incremental text content
`text-end`	Marks the end of a text block
`reasoning-start`	Marks the beginning of reasoning/thinking content
`reasoning-delta`	Incremental reasoning content
`reasoning-end`	Marks the end of reasoning content
`tool-input-start`	Marks the beginning of tool input streaming
`tool-input-delta`	Incremental tool input (JSON streaming)
`tool-input-end`	Marks the end of tool input
`tool-call`	Complete tool call with parsed input
`tool-result`	Tool execution result
`finish-step`	Marks the end of an agentic step
`finish`	Marks the end of the streaming session
`error`	Error during streaming

text-delta

Incremental text content from the agent.

interface TextDeltaPart {
  type: 'text-delta';
  id: string;          // Text block ID
  text: string;        // Text delta content
  metadata?: {
    parentToolUseId?: string;  // For subagent context
  };
}

tool-call

Complete tool call with parsed input arguments.

interface ToolCallPart {
  type: 'tool-call';
  toolCallId: string;              // Unique tool call ID
  toolName: string;                // Name of the tool
  input: Record<string, unknown>;  // Parsed input arguments
  metadata?: {
    parentToolUseId?: string;
  };
}

tool-result

Tool execution result.

interface ToolResultPart {
  type: 'tool-result';
  toolCallId: string;   // Tool call ID
  toolName: string;     // Name of the tool
  output?: unknown;     // Tool output
  metadata?: {
    parentToolUseId?: string;
  };
}

finish

Marks the end of the streaming session.

interface FinishPart {
  type: 'finish';
  finishReason: 'stop' | 'tool-calls' | 'length' | 'content-filter' | 'error' | 'other';
  totalUsage: {
    inputTokens: number;
    outputTokens: number;
    totalTokens?: number;
  };
  metadata?: {
    cost?: number;
    durationMs?: number;
  };
}

error

Error during streaming.

interface StreamErrorPart {
  type: 'error';
  error: string;         // Error message
  rawContent?: unknown;  // Original content that caused the error
}

These event types are designed to be compatible with the Vercel AI SDK streaming format, making it easy to integrate with AI SDK-based applications.

Path Parameters

task_id

string

required

Response

SSE stream of TextStreamPart events

Marks the start of a streaming session.

type

string

default:start

Allowed value: "start"

Migrate TasksMigrate tasks between versions within the same branch. Supports two modes: bulk migration by source version (from_version_id), or migration of specific tasks (task_ids). Target can be explicit (to_version_id) or latest active version (to_latest).

Stream Task Events by ID

curl --request GET \
  --url https://api.example.com/tasks/{task_id}/stream

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.example.com/tasks/{task_id}/stream",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "GET",
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"net/http"
	"io"
)

func main() {

	url := "https://api.example.com/tasks/{task_id}/stream"

	req, _ := http.NewRequest("GET", url, nil)

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

require 'uri'
require 'net/http'

url = URI("https://api.example.com/tasks/{task_id}/stream")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Get.new(url)

response = http.request(request)
puts response.read_body

{
  "type": "start"
}

{
  "detail": [
    {
      "loc": [
        "<string>"
      ],
      "msg": "<string>",
      "type": "<string>"
    }
  ]
}

Get Started

Core Concepts

Build Agents

Deploy & Operate

Security & Access

API

Stream Event Types

text-delta

tool-call

tool-result

finish

error

Path Parameters

Response

​Stream Event Types

​text-delta

​tool-call

​tool-result

​finish

​error

Path Parameters

Response

Stream Event Types

text-delta

tool-call

tool-result

finish

error