Invoke Agent (Stream)

Execute an agent task with real-time streaming responses. This endpoint returns Server-Sent Events (SSE) that provide live updates as the agent processes the task. Perfect for interactive applications and real-time user interfaces.

Path Parameters

agent_id

string

required

Unique identifier of the agent to invoke (UUID format)

Request Body

input

object

required

Agent execution input containing the task details

Show Input Object

text

string

The message or task to send to the agent. Either text or files must be provided.

files

array

Array of file URLs or file identifiers to process. Supports documents (PDF, DOCX, TXT), images (JPG, PNG), spreadsheets (CSV, XLSX), and more.Example: ["https://example.com/doc.pdf", "file-id-12345"]

user

object

User information for personalization and audit trail

Show User Object

string

Unique user identifier

first_name

string

User’s first name

last_name

string

User’s last name

string

required

User’s email address (required if user object is provided)

additional_attributes

object

Custom user metadata (e.g., {"customer_tier": "premium", "preferences": {...}})

output_format

string

Desired output format. Valid values: text | json | markdownDefault: text

text: Plain text response
json: Structured JSON output (use with output_schema for validation)
markdown: Formatted markdown response

output_schema

object

JSON Schema to validate and structure the agent’s output. When provided with output_format: "json", the agent will return data conforming to this schema.Example:

{
  "type": "object",
  "required": ["summary", "insights"],
  "properties": {
    "summary": {"type": "string"},
    "insights": {"type": "array", "items": {"type": "string"}}
  }
}

events_streaming

boolean

Enable detailed event streaming for granular progress tracking. When true, emits events for tool calls, intermediate steps, and execution progress.Default: falseRecommended: Set to true for this endpoint to get maximum visibility into agent execution.

additional_context

string

Additional context to guide the agent’s behavior. Use this to specify tone, audience, constraints, or background information.Example: "This is for executive leadership. Use professional tone and focus on business impact."

expected_output

string

Description of the expected output format, length, or structure. Helps guide the agent to produce the desired result.Example: "A 500-word summary with 3 key recommendations and supporting data."

title

string

Human-readable title for the task. Useful for identification and organization in task lists.Example: "Real-time Data Analysis"

parent_execution_id

string

UUID of the parent task if this is a sub-task. Used for multi-agent workflows and task hierarchies.Example: "550e8400-e29b-41d4-a716-446655440000"

triggering_agent_id

string

UUID of the agent that triggered this task. Used for tracking agent-to-agent delegation.Example: "7c9e6679-7425-40de-944b-e07fc1f90ae7"

payload_extension

object

Custom metadata to attach to the task. Any valid JSON object. Useful for tracking, routing, or application-specific data.Example:

{
  "request_id": "REQ-2025-001",
  "priority": "high",
  "stream_session_id": "stream-789"
}

mcp_servers

array

Array of Model Context Protocol (MCP) server configurations to use during execution. Enables integration with external tools and services.Example:

[
  {
    "name": "real-time-data",
    "config": {"refresh_interval": 5}
  }
]

source

string

Identifier for the source system or application that created this task. Useful for analytics and debugging.Example: "chat-widget" | "mobile-app" | "websocket-client"

string

Thread ID for conversation context. This ID is critical for multi-turn conversations:

If not provided: A UUID will be automatically generated (recommended for single-turn requests)
First message in conversation: Provide a unique UUID and save it for subsequent messages
Follow-up messages: Use the same id from the first request to maintain conversation history
The agent will remember all previous messages in the thread when you reuse the same ID

Example: "a37db9a1-e483-4544-9136-b32120ae8c81"

Multi-Turn Conversations: To enable the agent to remember previous messages, always use the same id for all requests in a conversation thread. Each unique id represents a separate conversation session. The response will include the same id (whether you provided it or it was auto-generated).

Example Requests

Basic Streaming Request

curl -X POST -H "x-api-key: YOUR_API_KEY" \
     -H "Content-Type: application/json" \
     -d '{
       "input": {
         "text": "Write a story about AI"
       }
     }' \
     https://api.xpander.ai/v1/agents/{agent_id}/invoke/stream

With Detailed Event Streaming

curl -X POST -H "x-api-key: YOUR_API_KEY" \
     -H "Content-Type: application/json" \
     -d '{
       "input": {
         "text": "Research AI trends and create a report"
       },
       "events_streaming": true,
       "title": "AI Trends Research"
     }' \
     https://api.xpander.ai/v1/agents/{agent_id}/invoke/stream

File Processing with Progress Tracking

curl -X POST -H "x-api-key: YOUR_API_KEY" \
     -H "Content-Type: application/json" \
     -d '{
       "input": {
         "text": "Analyze these documents",
         "files": [
           "https://example.com/report1.pdf",
           "https://example.com/report2.pdf"
         ]
       },
       "events_streaming": true,
       "output_format": "markdown",
       "additional_context": "Focus on key metrics and trends"
     }' \
     https://api.xpander.ai/v1/agents/{agent_id}/invoke/stream

Structured Output with Streaming

curl -X POST -H "x-api-key: YOUR_API_KEY" \
     -H "Content-Type: application/json" \
     -d '{
       "input": {
         "text": "Extract insights from customer feedback"
       },
       "output_format": "json",
       "output_schema": {
         "type": "object",
         "properties": {
           "sentiment": {"type": "string"},
           "themes": {"type": "array", "items": {"type": "string"}},
           "recommendations": {"type": "array", "items": {"type": "string"}}
         }
       },
       "events_streaming": true
     }' \
     https://api.xpander.ai/v1/agents/{agent_id}/invoke/stream

Multi-Turn Conversation (Streaming)

# First message - creates a new conversation thread
curl -X POST -H "x-api-key: YOUR_API_KEY" \
     -H "Content-Type: application/json" \
     -d '{
       "input": {
         "text": "My favorite color is blue"
       },
       "id": "stream-thread-789",
       "events_streaming": true
     }' \
     https://api.xpander.ai/v1/agents/{agent_id}/invoke/stream

# Follow-up message in the same thread
curl -X POST -H "x-api-key: YOUR_API_KEY" \
     -H "Content-Type: application/json" \
     -d '{
       "input": {
         "text": "What is my favorite color?"
       },
       "id": "stream-thread-789",
       "events_streaming": true
     }' \
     https://api.xpander.ai/v1/agents/{agent_id}/invoke/stream
# Agent will stream response: "Your favorite color is blue"

# Another follow-up with conversation history
curl -X POST -H "x-api-key: YOUR_API_KEY" \
     -H "Content-Type: application/json" \
     -d '{
       "input": {
         "text": "How many messages have I sent in this thread?"
       },
       "id": "stream-thread-789",
       "events_streaming": true
     }' \
     https://api.xpander.ai/v1/agents/{agent_id}/invoke/stream
# Agent will respond based on complete conversation history

Response Format

This endpoint returns Server-Sent Events (SSE) with Content-Type: text/event-stream

Event Stream Format

Events are sent in SSE format:

data: {"type": "task_started", "task_id": "...", "timestamp": "..."}

data: {"type": "content_chunk", "content": "...", "is_final": false}

data: {"type": "task_completed", "task_id": "...", "result": "..."}

Event Types

task_started

event

Sent when the task begins execution

Show Event Data

type

string

Event type: task_started

task_id

string

Unique identifier for the task (UUID)

timestamp

string

ISO 8601 timestamp of when the task started

content_chunk

event

Sent for each piece of generated content

Show Event Data

type

string

Event type: content_chunk

content

string

Partial content from the agent

is_final

boolean

Whether this is the final content chunk

task_completed

event

Sent when the task finishes successfully

Show Event Data

type

string

Event type: task_completed

task_id

string

Task identifier (UUID)

result

string

Complete task result content

error

event

Sent if an error occurs during execution

Show Event Data

type

string

Event type: error

error

string

Error message

Example: JavaScript Client

const response = await fetch('https://api.xpander.ai/v1/agents/{agent_id}/invoke/stream', {
  method: 'POST',
  headers: {
    'x-api-key': 'YOUR_API_KEY',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    input: {
      text: 'Analyze this data',
      files: []
    },
    events_streaming: true
  })
});

const reader = response.body.getReader();
const decoder = new TextDecoder();

while (true) {
  const { done, value } = await reader.read();
  if (done) break;
  
  const chunk = decoder.decode(value);
  const lines = chunk.split('\n');
  
  for (const line of lines) {
    if (line.startsWith('data: ')) {
      const event = JSON.parse(line.slice(6));
      console.log('Event:', event);
      
      if (event.type === 'task_completed') {
        console.log('Result:', event.result);
      }
    }
  }
}

Notes

The agent must have deployment_type: serverless or be a running container
Connection stays open until task completes or errors
Set appropriate timeout values for long-running tasks
Handle connection errors and implement retry logic
Multi-Turn Conversations: Use the same id parameter across requests to maintain conversation context. The agent will remember all previous messages in the thread and stream responses with full context awareness.

Overview

REST API - Agents

REST API - Tasks

REST API - Knowledge

REST API - Toolkits

REST API - Misc

Python SDK - Core Modules

Python SDK - API Reference

CLI Reference

Invoke Agent (Stream)

Path Parameters

Request Body

Example Requests

Basic Streaming Request

With Detailed Event Streaming

File Processing with Progress Tracking

Structured Output with Streaming

Multi-Turn Conversation (Streaming)

Response Format

Event Stream Format

Event Types

Example: JavaScript Client

Notes

See Also

Authorizations

Path Parameters

Body

Response

Overview

REST API - Agents

REST API - Tasks

REST API - Knowledge

REST API - Toolkits

REST API - Misc

Python SDK - Core Modules

Python SDK - API Reference

CLI Reference

​Path Parameters

​Request Body

​Example Requests

​Basic Streaming Request

​With Detailed Event Streaming

​File Processing with Progress Tracking

​Structured Output with Streaming

​Multi-Turn Conversation (Streaming)

​Response Format

​Event Stream Format

​Event Types

​Example: JavaScript Client

​Notes

​See Also

Authorizations

Path Parameters

Body

Response

Path Parameters

Request Body

Example Requests

Basic Streaming Request

With Detailed Event Streaming

File Processing with Progress Tracking

Structured Output with Streaming

Multi-Turn Conversation (Streaming)

Response Format

Event Stream Format

Event Types

Example: JavaScript Client

Notes

See Also