Streaming

Stream responses from agents and workflows for real-time interactions.

Topics

• Overview - Introduction to streaming
• Events - Streaming event types
• Tool Streaming - Stream tool execution
• Workflow Streaming - Stream workflow progress

Streaming Overview

Streaming enables real-time responses from agents and workflows.

Why Streaming?

• Faster perceived response time
• Real-time feedback during long operations
• Progressive disclosure of results
• Better user experience

Basic Streaming

const agent = mastra.getAgent('myAgent');

const stream = await agent.stream('Tell me a story');

for await (const chunk of stream) {
  process.stdout.write(chunk.text);
}

Stream Types

• Text streaming - Stream text tokens as they're generated
• Tool streaming - Stream tool execution progress
• Workflow streaming - Stream step completion and results

Tool Streaming

Stream tool execution progress and results.

Enabling Tool Streaming

const agent = mastra.getAgent('myAgent', {
  streaming: {
    tools: true,
  },
});

Tool Call Events

const stream = await agent.stream('Search for AI news');

stream.on('tool_call', (event) => {
  console.log('Calling tool:', event.tool);
  console.log('Input:', event.input);
});

stream.on('tool_start', (event) => {
  console.log('Tool execution started');
});

stream.on('tool_end', (event) => {
  console.log('Tool execution completed');
  console.log('Result:', event.result);
});

Tool Delta Streaming

For long-running tools, receive progressive updates:

stream.on('tool_delta', (event) => {
  console.log('Progress:', event.progress);
  console.log('Partial result:', event.partial);
});