feat: add streaming result support to flows and crews

* feat: add streaming result support to flows and crews
* docs: add streaming execution documentation and integration tests
This commit is contained in:
Greyson LaLonde
2025-11-24 15:43:48 -05:00
committed by GitHub
parent a978267fa2
commit f3c5d1e351
21 changed files with 15819 additions and 37 deletions

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@@ -33,6 +33,7 @@ A crew in crewAI represents a collaborative group of agents working together to
| **Planning** *(optional)* | `planning` | Adds planning ability to the Crew. When activated before each Crew iteration, all Crew data is sent to an AgentPlanner that will plan the tasks and this plan will be added to each task description. |
| **Planning LLM** *(optional)* | `planning_llm` | The language model used by the AgentPlanner in a planning process. |
| **Knowledge Sources** _(optional)_ | `knowledge_sources` | Knowledge sources available at the crew level, accessible to all the agents. |
| **Stream** _(optional)_ | `stream` | Enable streaming output to receive real-time updates during crew execution. Returns a `CrewStreamingOutput` object that can be iterated for chunks. Defaults to `False`. |
<Tip>
**Crew Max RPM**: The `max_rpm` attribute sets the maximum number of requests per minute the crew can perform to avoid rate limits and will override individual agents' `max_rpm` settings if you set it.
@@ -338,6 +339,29 @@ for async_result in async_results:
These methods provide flexibility in how you manage and execute tasks within your crew, allowing for both synchronous and asynchronous workflows tailored to your needs.
### Streaming Crew Execution
For real-time visibility into crew execution, you can enable streaming to receive output as it's generated:
```python Code
# Enable streaming
crew = Crew(
agents=[researcher],
tasks=[task],
stream=True
)
# Iterate over streaming output
streaming = crew.kickoff(inputs={"topic": "AI"})
for chunk in streaming:
print(chunk.content, end="", flush=True)
# Access final result
result = streaming.result
```
Learn more about streaming in the [Streaming Crew Execution](/en/learn/streaming-crew-execution) guide.
### Replaying from a Specific Task
You can now replay from a specific task using our CLI command `replay`.

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@@ -897,6 +897,31 @@ flow = ExampleFlow()
result = flow.kickoff()
```
### Streaming Flow Execution
For real-time visibility into flow execution, you can enable streaming to receive output as it's generated:
```python
class StreamingFlow(Flow):
stream = True # Enable streaming
@start()
def research(self):
# Your flow implementation
pass
# Iterate over streaming output
flow = StreamingFlow()
streaming = flow.kickoff()
for chunk in streaming:
print(chunk.content, end="", flush=True)
# Access final result
result = streaming.result
```
Learn more about streaming in the [Streaming Flow Execution](/en/learn/streaming-flow-execution) guide.
### Using the CLI
Starting from version 0.103.0, you can run flows using the `crewai run` command:

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@@ -0,0 +1,320 @@
---
title: Streaming Crew Execution
description: Stream real-time output from your CrewAI crew execution
icon: wave-pulse
mode: "wide"
---
## Introduction
CrewAI provides the ability to stream real-time output during crew execution, allowing you to display results as they're generated rather than waiting for the entire process to complete. This feature is particularly useful for building interactive applications, providing user feedback, and monitoring long-running processes.
## How Streaming Works
When streaming is enabled, CrewAI captures LLM responses and tool calls as they happen, packaging them into structured chunks that include context about which task and agent is executing. You can iterate over these chunks in real-time and access the final result once execution completes.
## Enabling Streaming
To enable streaming, set the `stream` parameter to `True` when creating your crew:
```python Code
from crewai import Agent, Crew, Task
# Create your agents and tasks
researcher = Agent(
role="Research Analyst",
goal="Gather comprehensive information on topics",
backstory="You are an experienced researcher with excellent analytical skills.",
)
task = Task(
description="Research the latest developments in AI",
expected_output="A detailed report on recent AI advancements",
agent=researcher,
)
# Enable streaming
crew = Crew(
agents=[researcher],
tasks=[task],
stream=True # Enable streaming output
)
```
## Synchronous Streaming
When you call `kickoff()` on a crew with streaming enabled, it returns a `CrewStreamingOutput` object that you can iterate over to receive chunks as they arrive:
```python Code
# Start streaming execution
streaming = crew.kickoff(inputs={"topic": "artificial intelligence"})
# Iterate over chunks as they arrive
for chunk in streaming:
print(chunk.content, end="", flush=True)
# Access the final result after streaming completes
result = streaming.result
print(f"\n\nFinal output: {result.raw}")
```
### Stream Chunk Information
Each chunk provides rich context about the execution:
```python Code
streaming = crew.kickoff(inputs={"topic": "AI"})
for chunk in streaming:
print(f"Task: {chunk.task_name} (index {chunk.task_index})")
print(f"Agent: {chunk.agent_role}")
print(f"Content: {chunk.content}")
print(f"Type: {chunk.chunk_type}") # TEXT or TOOL_CALL
if chunk.tool_call:
print(f"Tool: {chunk.tool_call.tool_name}")
print(f"Arguments: {chunk.tool_call.arguments}")
```
### Accessing Streaming Results
The `CrewStreamingOutput` object provides several useful properties:
```python Code
streaming = crew.kickoff(inputs={"topic": "AI"})
# Iterate and collect chunks
for chunk in streaming:
print(chunk.content, end="", flush=True)
# After iteration completes
print(f"\nCompleted: {streaming.is_completed}")
print(f"Full text: {streaming.get_full_text()}")
print(f"All chunks: {len(streaming.chunks)}")
print(f"Final result: {streaming.result.raw}")
```
## Asynchronous Streaming
For async applications, use `kickoff_async()` with async iteration:
```python Code
import asyncio
async def stream_crew():
crew = Crew(
agents=[researcher],
tasks=[task],
stream=True
)
# Start async streaming
streaming = await crew.kickoff_async(inputs={"topic": "AI"})
# Async iteration over chunks
async for chunk in streaming:
print(chunk.content, end="", flush=True)
# Access final result
result = streaming.result
print(f"\n\nFinal output: {result.raw}")
asyncio.run(stream_crew())
```
## Streaming with kickoff_for_each
When executing a crew for multiple inputs with `kickoff_for_each()`, streaming works differently depending on whether you use sync or async:
### Synchronous kickoff_for_each
With synchronous `kickoff_for_each()`, you get a list of `CrewStreamingOutput` objects, one for each input:
```python Code
crew = Crew(
agents=[researcher],
tasks=[task],
stream=True
)
inputs_list = [
{"topic": "AI in healthcare"},
{"topic": "AI in finance"}
]
# Returns list of streaming outputs
streaming_outputs = crew.kickoff_for_each(inputs=inputs_list)
# Iterate over each streaming output
for i, streaming in enumerate(streaming_outputs):
print(f"\n=== Input {i + 1} ===")
for chunk in streaming:
print(chunk.content, end="", flush=True)
result = streaming.result
print(f"\n\nResult {i + 1}: {result.raw}")
```
### Asynchronous kickoff_for_each_async
With async `kickoff_for_each_async()`, you get a single `CrewStreamingOutput` that yields chunks from all crews as they arrive concurrently:
```python Code
import asyncio
async def stream_multiple_crews():
crew = Crew(
agents=[researcher],
tasks=[task],
stream=True
)
inputs_list = [
{"topic": "AI in healthcare"},
{"topic": "AI in finance"}
]
# Returns single streaming output for all crews
streaming = await crew.kickoff_for_each_async(inputs=inputs_list)
# Chunks from all crews arrive as they're generated
async for chunk in streaming:
print(f"[{chunk.task_name}] {chunk.content}", end="", flush=True)
# Access all results
results = streaming.results # List of CrewOutput objects
for i, result in enumerate(results):
print(f"\n\nResult {i + 1}: {result.raw}")
asyncio.run(stream_multiple_crews())
```
## Stream Chunk Types
Chunks can be of different types, indicated by the `chunk_type` field:
### TEXT Chunks
Standard text content from LLM responses:
```python Code
for chunk in streaming:
if chunk.chunk_type == StreamChunkType.TEXT:
print(chunk.content, end="", flush=True)
```
### TOOL_CALL Chunks
Information about tool calls being made:
```python Code
for chunk in streaming:
if chunk.chunk_type == StreamChunkType.TOOL_CALL:
print(f"\nCalling tool: {chunk.tool_call.tool_name}")
print(f"Arguments: {chunk.tool_call.arguments}")
```
## Practical Example: Building a UI with Streaming
Here's a complete example showing how to build an interactive application with streaming:
```python Code
import asyncio
from crewai import Agent, Crew, Task
from crewai.types.streaming import StreamChunkType
async def interactive_research():
# Create crew with streaming enabled
researcher = Agent(
role="Research Analyst",
goal="Provide detailed analysis on any topic",
backstory="You are an expert researcher with broad knowledge.",
)
task = Task(
description="Research and analyze: {topic}",
expected_output="A comprehensive analysis with key insights",
agent=researcher,
)
crew = Crew(
agents=[researcher],
tasks=[task],
stream=True,
verbose=False
)
# Get user input
topic = input("Enter a topic to research: ")
print(f"\n{'='*60}")
print(f"Researching: {topic}")
print(f"{'='*60}\n")
# Start streaming execution
streaming = await crew.kickoff_async(inputs={"topic": topic})
current_task = ""
async for chunk in streaming:
# Show task transitions
if chunk.task_name != current_task:
current_task = chunk.task_name
print(f"\n[{chunk.agent_role}] Working on: {chunk.task_name}")
print("-" * 60)
# Display text chunks
if chunk.chunk_type == StreamChunkType.TEXT:
print(chunk.content, end="", flush=True)
# Display tool calls
elif chunk.chunk_type == StreamChunkType.TOOL_CALL and chunk.tool_call:
print(f"\n🔧 Using tool: {chunk.tool_call.tool_name}")
# Show final result
result = streaming.result
print(f"\n\n{'='*60}")
print("Analysis Complete!")
print(f"{'='*60}")
print(f"\nToken Usage: {result.token_usage}")
asyncio.run(interactive_research())
```
## Use Cases
Streaming is particularly valuable for:
- **Interactive Applications**: Provide real-time feedback to users as agents work
- **Long-Running Tasks**: Show progress for research, analysis, or content generation
- **Debugging and Monitoring**: Observe agent behavior and decision-making in real-time
- **User Experience**: Reduce perceived latency by showing incremental results
- **Live Dashboards**: Build monitoring interfaces that display crew execution status
## Important Notes
- Streaming automatically enables LLM streaming for all agents in the crew
- You must iterate through all chunks before accessing the `.result` property
- For `kickoff_for_each_async()` with streaming, use `.results` (plural) to get all outputs
- Streaming adds minimal overhead and can actually improve perceived performance
- Each chunk includes full context (task, agent, chunk type) for rich UIs
## Error Handling
Handle errors during streaming execution:
```python Code
streaming = crew.kickoff(inputs={"topic": "AI"})
try:
for chunk in streaming:
print(chunk.content, end="", flush=True)
result = streaming.result
print(f"\nSuccess: {result.raw}")
except Exception as e:
print(f"\nError during streaming: {e}")
if streaming.is_completed:
print("Streaming completed but an error occurred")
```
By leveraging streaming, you can build more responsive and interactive applications with CrewAI, providing users with real-time visibility into agent execution and results.

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@@ -0,0 +1,450 @@
---
title: Streaming Flow Execution
description: Stream real-time output from your CrewAI flow execution
icon: wave-pulse
mode: "wide"
---
## Introduction
CrewAI Flows support streaming output, allowing you to receive real-time updates as your flow executes. This feature enables you to build responsive applications that display results incrementally, provide live progress updates, and create better user experiences for long-running workflows.
## How Flow Streaming Works
When streaming is enabled on a Flow, CrewAI captures and streams output from any crews or LLM calls within the flow. The stream delivers structured chunks containing the content, task context, and agent information as execution progresses.
## Enabling Streaming
To enable streaming, set the `stream` attribute to `True` on your Flow class:
```python Code
from crewai.flow.flow import Flow, listen, start
from crewai import Agent, Crew, Task
class ResearchFlow(Flow):
stream = True # Enable streaming for the entire flow
@start()
def initialize(self):
return {"topic": "AI trends"}
@listen(initialize)
def research_topic(self, data):
researcher = Agent(
role="Research Analyst",
goal="Research topics thoroughly",
backstory="Expert researcher with analytical skills",
)
task = Task(
description="Research {topic} and provide insights",
expected_output="Detailed research findings",
agent=researcher,
)
crew = Crew(
agents=[researcher],
tasks=[task],
)
return crew.kickoff(inputs=data)
```
## Synchronous Streaming
When you call `kickoff()` on a flow with streaming enabled, it returns a `FlowStreamingOutput` object that you can iterate over:
```python Code
flow = ResearchFlow()
# Start streaming execution
streaming = flow.kickoff()
# Iterate over chunks as they arrive
for chunk in streaming:
print(chunk.content, end="", flush=True)
# Access the final result after streaming completes
result = streaming.result
print(f"\n\nFinal output: {result}")
```
### Stream Chunk Information
Each chunk provides context about where it originated in the flow:
```python Code
streaming = flow.kickoff()
for chunk in streaming:
print(f"Agent: {chunk.agent_role}")
print(f"Task: {chunk.task_name}")
print(f"Content: {chunk.content}")
print(f"Type: {chunk.chunk_type}") # TEXT or TOOL_CALL
```
### Accessing Streaming Properties
The `FlowStreamingOutput` object provides useful properties and methods:
```python Code
streaming = flow.kickoff()
# Iterate and collect chunks
for chunk in streaming:
print(chunk.content, end="", flush=True)
# After iteration completes
print(f"\nCompleted: {streaming.is_completed}")
print(f"Full text: {streaming.get_full_text()}")
print(f"Total chunks: {len(streaming.chunks)}")
print(f"Final result: {streaming.result}")
```
## Asynchronous Streaming
For async applications, use `kickoff_async()` with async iteration:
```python Code
import asyncio
async def stream_flow():
flow = ResearchFlow()
# Start async streaming
streaming = await flow.kickoff_async()
# Async iteration over chunks
async for chunk in streaming:
print(chunk.content, end="", flush=True)
# Access final result
result = streaming.result
print(f"\n\nFinal output: {result}")
asyncio.run(stream_flow())
```
## Streaming with Multi-Step Flows
Streaming works seamlessly across multiple flow steps, including flows that execute multiple crews:
```python Code
from crewai.flow.flow import Flow, listen, start
from crewai import Agent, Crew, Task
class MultiStepFlow(Flow):
stream = True
@start()
def research_phase(self):
"""First crew: Research the topic."""
researcher = Agent(
role="Research Analyst",
goal="Gather comprehensive information",
backstory="Expert at finding relevant information",
)
task = Task(
description="Research AI developments in healthcare",
expected_output="Research findings on AI in healthcare",
agent=researcher,
)
crew = Crew(agents=[researcher], tasks=[task])
result = crew.kickoff()
self.state["research"] = result.raw
return result.raw
@listen(research_phase)
def analysis_phase(self, research_data):
"""Second crew: Analyze the research."""
analyst = Agent(
role="Data Analyst",
goal="Analyze information and extract insights",
backstory="Expert at identifying patterns and trends",
)
task = Task(
description="Analyze this research: {research}",
expected_output="Key insights and trends",
agent=analyst,
)
crew = Crew(agents=[analyst], tasks=[task])
return crew.kickoff(inputs={"research": research_data})
# Stream across both phases
flow = MultiStepFlow()
streaming = flow.kickoff()
current_step = ""
for chunk in streaming:
# Track which flow step is executing
if chunk.task_name != current_step:
current_step = chunk.task_name
print(f"\n\n=== {chunk.task_name} ===\n")
print(chunk.content, end="", flush=True)
result = streaming.result
print(f"\n\nFinal analysis: {result}")
```
## Practical Example: Progress Dashboard
Here's a complete example showing how to build a progress dashboard with streaming:
```python Code
import asyncio
from crewai.flow.flow import Flow, listen, start
from crewai import Agent, Crew, Task
from crewai.types.streaming import StreamChunkType
class ResearchPipeline(Flow):
stream = True
@start()
def gather_data(self):
researcher = Agent(
role="Data Gatherer",
goal="Collect relevant information",
backstory="Skilled at finding quality sources",
)
task = Task(
description="Gather data on renewable energy trends",
expected_output="Collection of relevant data points",
agent=researcher,
)
crew = Crew(agents=[researcher], tasks=[task])
result = crew.kickoff()
self.state["data"] = result.raw
return result.raw
@listen(gather_data)
def analyze_data(self, data):
analyst = Agent(
role="Data Analyst",
goal="Extract meaningful insights",
backstory="Expert at data analysis",
)
task = Task(
description="Analyze: {data}",
expected_output="Key insights and trends",
agent=analyst,
)
crew = Crew(agents=[analyst], tasks=[task])
return crew.kickoff(inputs={"data": data})
async def run_with_dashboard():
flow = ResearchPipeline()
print("="*60)
print("RESEARCH PIPELINE DASHBOARD")
print("="*60)
streaming = await flow.kickoff_async()
current_agent = ""
current_task = ""
chunk_count = 0
async for chunk in streaming:
chunk_count += 1
# Display phase transitions
if chunk.task_name != current_task:
current_task = chunk.task_name
current_agent = chunk.agent_role
print(f"\n\n📋 Phase: {current_task}")
print(f"👤 Agent: {current_agent}")
print("-" * 60)
# Display text output
if chunk.chunk_type == StreamChunkType.TEXT:
print(chunk.content, end="", flush=True)
# Display tool usage
elif chunk.chunk_type == StreamChunkType.TOOL_CALL and chunk.tool_call:
print(f"\n🔧 Tool: {chunk.tool_call.tool_name}")
# Show completion summary
result = streaming.result
print(f"\n\n{'='*60}")
print("PIPELINE COMPLETE")
print(f"{'='*60}")
print(f"Total chunks: {chunk_count}")
print(f"Final output length: {len(str(result))} characters")
asyncio.run(run_with_dashboard())
```
## Streaming with State Management
Streaming works naturally with Flow state management:
```python Code
from pydantic import BaseModel
class AnalysisState(BaseModel):
topic: str = ""
research: str = ""
insights: str = ""
class StatefulStreamingFlow(Flow[AnalysisState]):
stream = True
@start()
def research(self):
# State is available during streaming
topic = self.state.topic
print(f"Researching: {topic}")
researcher = Agent(
role="Researcher",
goal="Research topics thoroughly",
backstory="Expert researcher",
)
task = Task(
description=f"Research {topic}",
expected_output="Research findings",
agent=researcher,
)
crew = Crew(agents=[researcher], tasks=[task])
result = crew.kickoff()
self.state.research = result.raw
return result.raw
@listen(research)
def analyze(self, research):
# Access updated state
print(f"Analyzing {len(self.state.research)} chars of research")
analyst = Agent(
role="Analyst",
goal="Extract insights",
backstory="Expert analyst",
)
task = Task(
description="Analyze: {research}",
expected_output="Key insights",
agent=analyst,
)
crew = Crew(agents=[analyst], tasks=[task])
result = crew.kickoff(inputs={"research": research})
self.state.insights = result.raw
return result.raw
# Run with streaming
flow = StatefulStreamingFlow()
streaming = flow.kickoff(inputs={"topic": "quantum computing"})
for chunk in streaming:
print(chunk.content, end="", flush=True)
result = streaming.result
print(f"\n\nFinal state:")
print(f"Topic: {flow.state.topic}")
print(f"Research length: {len(flow.state.research)}")
print(f"Insights length: {len(flow.state.insights)}")
```
## Use Cases
Flow streaming is particularly valuable for:
- **Multi-Stage Workflows**: Show progress across research, analysis, and synthesis phases
- **Complex Pipelines**: Provide visibility into long-running data processing flows
- **Interactive Applications**: Build responsive UIs that display intermediate results
- **Monitoring and Debugging**: Observe flow execution and crew interactions in real-time
- **Progress Tracking**: Show users which stage of the workflow is currently executing
- **Live Dashboards**: Create monitoring interfaces for production flows
## Stream Chunk Types
Like crew streaming, flow chunks can be of different types:
### TEXT Chunks
Standard text content from LLM responses:
```python Code
for chunk in streaming:
if chunk.chunk_type == StreamChunkType.TEXT:
print(chunk.content, end="", flush=True)
```
### TOOL_CALL Chunks
Information about tool calls within the flow:
```python Code
for chunk in streaming:
if chunk.chunk_type == StreamChunkType.TOOL_CALL and chunk.tool_call:
print(f"\nTool: {chunk.tool_call.tool_name}")
print(f"Args: {chunk.tool_call.arguments}")
```
## Error Handling
Handle errors gracefully during streaming:
```python Code
flow = ResearchFlow()
streaming = flow.kickoff()
try:
for chunk in streaming:
print(chunk.content, end="", flush=True)
result = streaming.result
print(f"\nSuccess! Result: {result}")
except Exception as e:
print(f"\nError during flow execution: {e}")
if streaming.is_completed:
print("Streaming completed but flow encountered an error")
```
## Important Notes
- Streaming automatically enables LLM streaming for any crews used within the flow
- You must iterate through all chunks before accessing the `.result` property
- Streaming works with both structured and unstructured flow state
- Flow streaming captures output from all crews and LLM calls in the flow
- Each chunk includes context about which agent and task generated it
- Streaming adds minimal overhead to flow execution
## Combining with Flow Visualization
You can combine streaming with flow visualization to provide a complete picture:
```python Code
# Generate flow visualization
flow = ResearchFlow()
flow.plot("research_flow") # Creates HTML visualization
# Run with streaming
streaming = flow.kickoff()
for chunk in streaming:
print(chunk.content, end="", flush=True)
result = streaming.result
print(f"\nFlow complete! View structure at: research_flow.html")
```
By leveraging flow streaming, you can build sophisticated, responsive applications that provide users with real-time visibility into complex multi-stage workflows, making your AI automations more transparent and engaging.