
crewai-developer
Comprehensive CrewAI framework guide for building collaborative AI agent teams and structured workflows. Use when developing multi-agent systems with CrewAI, creating autonomous AI crews, orchestrating flows, implementing agents with roles and tools, or building production-ready AI automation. Essential for developers building intelligent agent systems, task automation, and complex AI workflows.
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Install
Works with every agent the skills CLI supports.
npx skills add https://github.com/smallnest/langgraphgo --skill crewai-developer- 01
Install
Run the command in your project. The CLI asks which agents to install for.
- 02
Describe the task
Ask your agent for something this skill covers. It loads crewai-developer automatically when relevant.
- 03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.
SKILL.md
The instructions your agent reads when the skill is triggered.
CrewAI Developer Guide
Overview
CrewAI is a lean, lightning-fast Python framework for building collaborative AI agent teams and structured workflows. It empowers developers to create autonomous AI agents with specific roles, tools, and goals that work together to tackle complex tasks. This skill covers Crews (autonomous collaboration), Flows (structured orchestration), agents, tasks, and enterprise deployment.
Core Concepts
Agents: Specialized Team Members
Agents are autonomous AI units with specific roles, goals, and capabilities.
from crewai import Agent
# Create a research agent
researcher = Agent(
role='Senior Research Analyst',
goal='Uncover cutting-edge developments in AI and data science',
backstory="""You are an expert at a leading tech think tank.
Your expertise lies in identifying emerging trends and technologies in AI,
data science, and machine learning.""",
verbose=True,
allow_delegation=False,
tools=[search_tool, scrape_tool]
)
# Create a writer agent
writer = Agent(
role='Tech Content Strategist',
goal='Craft compelling content on tech advancements',
backstory="""You are a renowned content strategist, known for
your insightful and engaging articles on technology and innovation.
You transform complex concepts into compelling narratives.""",
verbose=True,
allow_delegation=True,
tools=[write_tool]
)
Agent Key Properties
agent = Agent(
role='Role Name', # The agent's job title
goal='Specific objective', # What the agent aims to achieve
backstory='Background story', # Context and expertise
verbose=True, # Enable detailed logging
allow_delegation=False, # Can delegate tasks to other agents
tools=[tool1, tool2], # Available tools
llm=custom_llm, # Custom LLM configuration
max_iter=15, # Maximum iterations for task
max_rpm=10, # Rate limit (requests per minute)
memory=True, # Enable memory
cache=True, # Enable response caching
system_template="template", # Custom system prompt template
prompt_template="template", # Custom prompt template
response_template="template" # Custom response template
)
Tasks: Individual Assignments
Tasks define specific work to be completed by agents.
from crewai import Task
# Research task
research_task = Task(
description="""Conduct a comprehensive analysis of the latest advancements in AI.
Identify key trends, breakthrough technologies, and potential industry impacts.
Compile your findings in a detailed report.""",
expected_output='A comprehensive 3-paragraph report on AI advancements',
agent=researcher,
tools=[search_tool],
output_file='research_report.md'
)
# Writing task
write_task = Task(
description="""Using the research analyst's report, develop an engaging blog post
highlighting the most significant AI advancements.
Make it accessible and engaging for a general audience.""",
expected_output='A 4-paragraph blog post about AI advancements',
agent=writer,
context=[research_task], # Depends on research_task output
output_file='blog_post.md'
)
Task Key Properties
task = Task(
description='Detailed task description',
expected_output='Clear output format',
agent=agent_instance,
tools=[tool1, tool2], # Task-specific tools
context=[previous_task], # Dependencies
async_execution=False, # Run asynchronously
output_json=OutputClass, # Structured output (Pydantic)
output_pydantic=OutputClass, # Pydantic validation
output_file='result.txt', # Save output to file
callback=callback_function, # Callback on completion
human_input=False # Request human feedback
)
Crews: Organizing Agent Teams
Crews orchestrate agents working together toward a common goal.
from crewai import Crew, Process
# Create a crew
crew = Crew(
agents=[researcher, writer],
tasks=[research_task, write_task],
process=Process.sequential, # or Process.hierarchical
verbose=True,
memory=True,
cache=True,
max_rpm=10,
share_crew=False
)
# Kickoff the crew
result = crew.kickoff()
print(result)
# Kickoff with custom inputs
result = crew.kickoff(inputs={
'topic': 'Artificial Intelligence',
'audience': 'developers'
})
Process Types
# Sequential process (tasks run one after another)
crew = Crew(
agents=[agent1, agent2],
tasks=[task1, task2],
process=Process.sequential
)
# Hierarchical process (manager delegates to agents)
crew = Crew(
agents=[agent1, agent2],
tasks=[task1, task2],
process=Process.hierarchical,
manager_llm='gpt-4' # Required for hierarchical
)
Flows: Structured Workflow Orchestration
Flows provide event-driven, deterministic control over execution paths.
from crewai.flow.flow import Flow, listen, start
class BlogPostFlow(Flow):
@start()
def fetch_topic(self):
"""Entry point - fetch the topic to write about"""
print("Starting blog post generation")
return "AI advancements in 2024"
@listen(fetch_topic)
def research_topic(self, topic):
"""Research the topic"""
print(f"Researching: {topic}")
# Integrate with Crew for autonomous research
research_crew = Crew(
agents=[researcher],
tasks=[research_task]
)
result = research_crew.kickoff(inputs={'topic': topic})
return result
@listen(research_topic)
def write_blog_post(self, research_data):
"""Write the blog post"""
print("Writing blog post...")
write_crew = Crew(
agents=[writer],
tasks=[write_task]
)
result = write_crew.kickoff(inputs={'research': research_data})
return result
@listen(write_blog_post)
def finalize(self, blog_post):
"""Finalize and save"""
print("Blog post completed!")
return blog_post
# Execute flow
flow = BlogPostFlow()
result = flow.kickoff()
Flow State Management
from crewai.flow.flow import Flow, listen, start
from pydantic import BaseModel
class ArticleState(BaseModel):
topic: str = ""
research: str = ""
draft: str = ""
final: str = ""
class ArticleFlow(Flow[ArticleState]):
@start()
def set_topic(self):
self.state.topic = "AI Ethics"
return self.state.topic
@listen(set_topic)
def research(self, topic):
# Research logic
self.state.research = "Research findings..."
return self.state.research
@listen(research)
def write_draft(self, research):
self.state.draft = "Draft content..."
return self.state.draft
# Access state
flow = ArticleFlow()
flow.kickoff()
print(flow.state.topic)
print(flow.state.research)
Router Pattern
from crewai.flow.flow import Flow, listen, start, router
class ContentFlow(Flow):
@start()
def categorize_content(self):
return "technical" # or "marketing", "blog"
@router(categorize_content)
def route_content(self, category):
if category == "technical":
return "write_technical"
elif category == "marketing":
return "write_marketing"
else:
return "write_blog"
@listen("write_technical")
def write_technical_doc(self):
return "Technical documentation..."
@listen("write_marketing")
def write_marketing_copy(self):
return "Marketing content..."
@listen("write_blog")
def write_blog_post(self):
return "Blog post..."
Tools: Extending Agent Capabilities
Built-in Tools
from crewai_tools import (
SerperDevTool, # Google search
ScrapeWebsiteTool, # Web scraping
FileReadTool, # Read files
DirectoryReadTool, # Read directories
CodeDocsSearchTool, # Search code documentation
CSVSearchTool, # Search CSV files
JSONSearchTool, # Search JSON files
MDXSearchTool, # Search MDX files
PDFSearchTool, # Search PDF files
TXTSearchTool, # Search text files
WebsiteSearchTool, # Search websites
SeleniumScrapingTool, # Browser automation
YoutubeChannelSearchTool, # YouTube search
YoutubeVideoSearchTool # YouTube video search
)
# Using tools
search_tool = SerperDevTool()
scrape_tool = ScrapeWebsiteTool()
file_tool = FileReadTool()
agent = Agent(
role='Researcher',
tools=[search_tool, scrape_tool, file_tool]
)
Custom Tools
from crewai_tools import BaseTool
class MyCustomTool(BaseTool):
name: str = "Custom Tool Name"
description: str = "Clear description of what the tool does"
def _run(self, argument: str) -> str:
# Implementation
result = perform_operation(argument)
return result
# Using custom tool
custom_tool = MyCustomTool()
agent = Agent(
role='Specialist',
tools=[custom_tool]
)
Function as Tool
from crewai import Agent
def calculate_sum(a: int, b: int) -> int:
"""Calculate the sum of two numbers"""
return a + b
agent = Agent(
role='Calculator',
tools=[calculate_sum] # Pass function directly
)
Memory: Learning from Past Interactions
from crewai import Crew, Agent, Task
# Enable crew memory
crew = Crew(
agents=[agent1, agent2],
tasks=[task1, task2],
memory=True, # Enable all memory types
verbose=True
)
# Configure specific memory types
crew = Crew(
agents=[agent1, agent2],
tasks=[task1, task2],
memory=True,
memory_config={
'short_term': True, # Remember within single run
'long_term': True, # Remember across runs
'entity': True # Remember entities (people, places)
}
)
Knowledge: RAG Integration
from crewai import Agent, Crew, Task, knowledge
# Create knowledge source
docs_knowledge = knowledge.StringKnowledgeSource(
content="Company policies and procedures...",
metadata={"source": "policy_docs"}
)
# Using knowledge in agent
agent = Agent(
role='Policy Expert',
goal='Answer questions about company policies',
backstory='Expert in company policies',
knowledge_sources=[docs_knowledge]
)
# Load knowledge from files
pdf_knowledge = knowledge.PDFKnowledgeSource(
file_path='./documents/handbook.pdf'
)
txt_knowledge = knowledge.TextKnowledgeSource(
file_path='./documents/faq.txt'
)
agent = Agent(
role='Support Agent',
knowledge_sources=[pdf_knowledge, txt_knowledge]
)
Structured Outputs with Pydantic
from pydantic import BaseModel
from crewai import Task, Agent
class BlogPost(BaseModel):
title: str
content: str
tags: list[str]
word_count: int
# Task with structured output
write_task = Task(
description='Write a blog post about AI',
expected_output='Blog post with title, content, tags, and word count',
agent=writer,
output_pydantic=BlogPost
)
# Execute and get structured output
result = crew.kickoff()
blog_post: BlogPost = write_task.output.pydantic
print(blog_post.title)
print(blog_post.tags)
Training: Improving Performance
from crewai import Crew
crew = Crew(
agents=[agent1, agent2],
tasks=[task1, task2]
)
# Training loop
crew.train(
n_iterations=10,
inputs={'topic': 'AI'},
filename='trained_crew.pkl'
)
# Load trained crew
trained_crew = Crew.load('trained_crew.pkl')
Human-in-the-Loop
from crewai import Task
# Task requiring human input
review_task = Task(
description='Review the draft and provide feedback',
expected_output='Approved draft or feedback for revision',
agent=editor,
human_input=True # Will pause and ask for input
)
# Conditional human input
task = Task(
description='Generate report',
expected_output='Final report',
agent=analyst,
callback=lambda output: validate_output(output),
human_input=True if needs_review else False
)
Testing Crews
from crewai import Crew
import pytest
def test_research_crew():
# Setup
crew = Crew(
agents=[researcher],
tasks=[research_task]
)
# Execute
result = crew.kickoff(inputs={'topic': 'AI'})
# Assert
assert result is not None
assert 'AI' in result
assert len(result) > 100
def test_crew_with_mock():
# Mock agent behavior for testing
mock_agent = Agent(
role='Mock Agent',
goal='Return test data',
backstory='Test agent'
)
mock_task = Task(
description='Test task',
expected_output='Test output',
agent=mock_agent
)
crew = Crew(agents=[mock_agent], tasks=[mock_task])
result = crew.kickoff()
assert result == 'Test output'
Custom LLMs
from langchain_openai import ChatOpenAI
from crewai import Agent, Crew
# Using custom LLM
custom_llm = ChatOpenAI(
model='gpt-4-turbo-preview',
temperature=0.7,
max_tokens=2000
)
agent = Agent(
role='Writer',
llm=custom_llm
)
# Crew-level LLM
crew = Crew(
agents=[agent1, agent2],
tasks=[task1, task2],
manager_llm=custom_llm # For hierarchical process
)
Async Execution
from crewai import Crew
crew = Crew(
agents=[agent1, agent2],
tasks=[task1, task2]
)
# Async kickoff
async def run_crew():
result = await crew.kickoff_async(inputs={'topic': 'AI'})
return result
# Kickoff for each (parallel execution)
inputs_list = [
{'topic': 'AI'},
{'topic': 'ML'},
{'topic': 'Data Science'}
]
results = crew.kickoff_for_each(inputs=inputs_list)
Callbacks and Event Listeners
from crewai import Task, Agent
def on_task_complete(output):
print(f"Task completed with output: {output}")
# Log, notify, or process output
def on_task_error(error):
print(f"Task failed with error: {error}")
# Handle error, retry, or notify
task = Task(
description='Analyze data',
expected_output='Analysis report',
agent=analyst,
callback=on_task_complete
)
# Agent-level callbacks
agent = Agent(
role='Analyst',
step_callback=lambda step: print(f"Agent step: {step}"),
task_callback=on_task_complete
)
Enterprise Deployment
Environment Configuration
import os
# API keys
os.environ['OPENAI_API_KEY'] = 'your-key'
os.environ['SERPER_API_KEY'] = 'your-key'
# CrewAI+ (Enterprise)
os.environ['CREWAI_API_KEY'] = 'your-enterprise-key'
# Observability
os.environ['LANGCHAIN_TRACING_V2'] = 'true'
os.environ['LANGCHAIN_API_KEY'] = 'your-langchain-key'
Project Structure
my_crew_project/
├── src/
│ └── my_crew_project/
│ ├── __init__.py
│ ├── main.py
│ ├── crew.py
│ ├── config/
│ │ ├── agents.yaml
│ │ └── tasks.yaml
│ └── tools/
│ └── custom_tool.py
├── tests/
│ └── test_crew.py
├── pyproject.toml
└── README.md
YAML Configuration
agents.yaml
researcher:
role: >
Senior Research Analyst
goal: >
Uncover cutting-edge developments in {topic}
backstory: >
You are an expert researcher with deep knowledge in {topic}
writer:
role: >
Content Writer
goal: >
Create engaging content about {topic}
backstory: >
You are a skilled writer who makes complex topics accessible
tasks.yaml
research_task:
description: >
Conduct comprehensive research on {topic}
expected_output: >
A detailed research report with key findings
agent: researcher
writing_task:
description: >
Write an article based on the research
expected_output: >
A well-structured article
agent: writer
context:
- research_task
Best Practices
Agent Design
✅ Good Practices:
- Give agents clear, specific roles
- Provide detailed backstories for context
- Limit tools to what's necessary
- Enable delegation for managers
- Use verbose mode during development
❌ Avoid:
- Vague or overlapping roles
- Too many tools (causes confusion)
- Missing backstories
- Overly complex goals
Task Design
✅ Good Practices:
- Write clear, actionable descriptions
- Specify expected output format
- Set up proper task dependencies
- Use context for task chaining
- Enable human input for critical decisions
❌ Avoid:
- Ambiguous descriptions
- Missing expected output
- Circular dependencies
- Overly complex single tasks
Crew Organization
✅ Good Practices:
- Start with sequential process
- Use hierarchical for complex coordination
- Enable memory for context retention
- Set reasonable rate limits
- Test with small datasets first
❌ Avoid:
- Too many agents (3-5 is optimal)
- Complex hierarchies without testing
- Disabled memory in multi-step flows
- No rate limiting
Common Patterns
Research and Write Pipeline
# 1. Research agent gathers information
# 2. Analyst agent processes data
# 3. Writer agent creates content
# 4. Editor agent reviews and refines
researcher = Agent(role='Researcher', ...)
analyst = Agent(role='Analyst', ...)
writer = Agent(role='Writer', ...)
editor = Agent(role='Editor', ...)
research = Task(agent=researcher, ...)
analysis = Task(agent=analyst, context=[research], ...)
draft = Task(agent=writer, context=[analysis], ...)
final = Task(agent=editor, context=[draft], ...)
crew = Crew(
agents=[researcher, analyst, writer, editor],
tasks=[research, analysis, draft, final],
process=Process.sequential
)
Multi-Stage Approval Flow
class ApprovalFlow(Flow):
@start()
def create_draft(self):
# Generate initial draft
return draft_content
@listen(create_draft)
def request_review(self, draft):
# Send for review
return review_request
@router(request_review)
def check_approval(self, review):
if review.approved:
return "finalize"
else:
return "revise"
@listen("revise")
def revise_draft(self):
# Revise and loop back
return revised_draft
@listen("finalize")
def finalize_content(self):
return final_content
Quick Reference
Installation
# Using uv (recommended)
uv pip install crewai crewai-tools
# Using pip
pip install crewai crewai-tools
# With all extras
pip install 'crewai[all]'
CLI Commands
# Create new project
crewai create crew my_project
# Create flow
crewai create flow my_flow
# Install dependencies
crewai install
# Run project
crewai run
# Train crew
crewai train
# Replay task
crewai replay <task_id>
# Test crew
crewai test
Essential Imports
from crewai import Agent, Task, Crew, Process
from crewai.flow.flow import Flow, listen, start, router
from crewai_tools import SerperDevTool, ScrapeWebsiteTool
from pydantic import BaseModel
Resources
For advanced patterns, integration examples, and troubleshooting:
- Official Documentation: https://docs.crewai.com/
- API Reference: https://docs.crewai.com/api-reference
- GitHub: https://github.com/joaomdmoura/crewAI
- Community Forum: https://community.crewai.com/
Extended Reference
See references/advanced_patterns.md for:
- MCP (Model Context Protocol) integration
- Observability and tracing setup
- Production deployment strategies
- Advanced flow patterns
- Performance optimization
FAQ
What does the crewai-developer skill do?
Comprehensive CrewAI framework guide for building collaborative AI agent teams and structured workflows. Use when developing multi-agent systems with CrewAI, creating autonomous AI crews, orchestrating flows, implementing agents with roles and tools, or building production-ready AI automation. Essential for developers building intelligent agent systems, task automation, and complex AI workflows.
How do I install crewai-developer?
Run npx skills add https://github.com/smallnest/langgraphgo --skill crewai-developer in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/crewai-developer/ (personal) or .claude/skills/crewai-developer/ (project).
Which AI agents can use crewai-developer?
Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.
Is crewai-developer safe to install?
No partner security audit is available yet. Skills can run commands and scripts, so read the SKILL.md and any bundled files before installing.
Who maintains crewai-developer?
It is published by smallnest in smallnest/langgraphgo. It has 41 recorded installs.
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