AI Agent Frameworks

AI Agent Frameworks Skill

When to Use This Skill

Invoke this skill when working with multi-agent AI systems, including:

• Selecting between CrewAI, LangChain, AutoGen, LangGraph, or custom agent architectures
• Designing multi-agent collaboration patterns
• Implementing agent workflows with proper observability
• Debugging stuck agents, infinite loops, or runaway costs
• Integrating agents with MCP servers and external tools
• Deploying agent systems to production
• Recognizing when agents add unnecessary complexity

Framework Selection Decision Process

Decision Tree

Start by determining if agents are truly needed:

Question 1: Is multi-step reasoning or tool orchestration required?

• If NO → Use a single LLM call or simple chain
• If YES → Continue

Question 2: Does the workflow map to clear team roles (research, write, edit)?

• If YES → Prefer CrewAI for its role-based simplicity
• If NO → Continue

Question 3: Is RAG (Retrieval-Augmented Generation) central to the application?

• If YES → Prefer LangChain for best-in-class RAG capabilities
• If NO → Continue

Question 4: Do agents need conversational debate or consensus-reaching?

• If YES → Consider AutoGen for conversation patterns
• If NO → Continue

Question 5: Does the workflow require complex state machines with loops and branching?

• If YES → Consider LangGraph for stateful control
• If NO → Continue

Question 6: Are minimal dependencies and maximum control essential?

• If YES → Build custom agent system
• If NO → Default to LangChain (most versatile)

Quick Framework Comparison Reference

For detailed comparisons, refer to references/framework-comparison.md

• CrewAI: Best for role-based teams, sequential workflows, quick prototypes
• LangChain: Best for RAG, extensive integrations, production tooling (LangSmith)
• AutoGen: Best for conversational agents, code execution, research projects
• LangGraph: Best for complex stateful workflows requiring loops and retries
• Custom: Best for simple use cases, performance-critical systems, unique requirements

Agent Architecture Patterns

Single-Agent vs Multi-Agent Criteria

Use single agent when:

• Task is straightforward with clear steps
• No benefit from specialization
• Cost and complexity must be minimized

Use multi-agent when:

• Tasks benefit from specialized expertise (research vs writing vs review)
• Parallel execution would improve performance
• Different agents need different models or tools
• Workflow involves handoffs or collaboration

Common Orchestration Patterns

Sequential Pattern:

Agent A → Agent B → Agent C

• Use when each step depends on previous output
• Examples: Research → Write → Edit → Publish

Parallel Pattern:

      → Agent A →
Input → Agent B → Merge → Output
      → Agent C →

• Use when tasks are independent and can run concurrently
• Examples: Parallel research from multiple sources

Hierarchical Pattern:

     Manager Agent
    /      |      \
Agent A  Agent B  Agent C

• Use when dynamic task allocation is needed
• Manager delegates and coordinates

Conversational Pattern:

Agent A ⟷ Agent B ⟷ Agent C

• Use for debate, consensus, or iterative refinement
• Common in AutoGen workflows

Framework-Specific Guidance

When Working with CrewAI

Refer to references/crewai-patterns.md for comprehensive patterns.

Key principles:

• Design agents with specific roles (not generic "helper")
• Keep 2-5 agents per workflow (avoid over-engineering)
• Use sequential process for predictable workflows
• Use hierarchical process when dynamic delegation is needed
• Set max_iterations to prevent runaway costs

Common anti-pattern to avoid:

# ❌ Don't: Vague agents with overlapping responsibilities
agent = Agent(role="Helper", goal="Help with stuff")

# ✅ Do: Specific agents with clear boundaries
researcher = Agent(
    role="Technical Researcher",
    goal="Find accurate data on Python frameworks",
    tools=[search_tool, docs_tool]
)

When Working with LangChain

Refer to references/langchain-patterns.md for comprehensive patterns.

Key principles:

• Always set max_iterations on AgentExecutor to prevent loops
• Use LCEL (| operator) for composing chains
• Enable LangSmith tracing in production
• Implement proper error handling with handle_parsing_errors=True
• Consider using GPT-3.5-turbo for simple agents to reduce costs

RAG pattern (common use case):

from langchain.chains import RetrievalQA

qa_chain = RetrievalQA.from_chain_type(
    llm=llm,
    retriever=vectorstore.as_retriever(search_kwargs={"k": 4}),
    return_source_documents=True
)

Critical: Always limit iterations:

agent_executor = AgentExecutor(
    agent=agent,
    tools=tools,
    max_iterations=10,  # REQUIRED
    max_execution_time=60,
    handle_parsing_errors=True
)

When Working with AutoGen

Refer to references/autogen-patterns.md for comprehensive patterns.

Key principles:

• Always use Docker for code execution in production (use_docker=True)
• Set max_round on GroupChat to prevent infinite conversations
• Use human_input_mode appropriately (NEVER, TERMINATE, or ALWAYS)
• Keep group chats to 3-5 agents maximum
• Track token usage as conversations can be expensive

Safe code execution:

user_proxy = UserProxyAgent(
    name="executor",
    code_execution_config={
        "use_docker": True,  # CRITICAL for production
        "timeout": 60
    }
)

When Building Custom Agents

Refer to references/custom-agent-guide.md for complete implementations.

Build custom when:

• Single-purpose agent with minimal complexity
• Framework overhead is unjustified
• Need maximum performance control
• Learning exercise to understand agents deeply

Minimal implementation pattern:

1. Prompt template
2. LLM client with retry logic
3. Tool execution with error handling
4. Response parsing

Production-ready custom agent includes:

• Timeout protection
• Retry logic with exponential backoff
• Cost tracking
• Comprehensive logging
• Circuit breakers for external APIs

Debugging Stuck or Looping Agents

Detection Strategies

Loop detection:

• Track action history (last 3-5 actions)
• Alert when same action repeats consecutively
• Implement max_iterations as hard stop

Stuck detection:

• Set execution timeouts (30-60 seconds per agent)
• Monitor for agents waiting indefinitely
• Check for missing tool results

Tools available:

• Use scripts/agent-debugger.py to analyze trace files
• Examine span durations to identify bottlenecks
• Look for repeated patterns in execution logs

Common Causes and Solutions

Cause: Agent keeps calling the same tool with same parameters Solution: Improve prompt to guide agent away from repetition, implement action history in context

Cause: Agent waiting for tool that never completes Solution: Add timeouts to all tool calls, implement circuit breakers

Cause: Agent confused about when to terminate Solution: Clear termination conditions, explicit TERMINATE signals

Tool Integration Best Practices

MCP Server Integration

When integrating MCP servers with agent frameworks:

With LangChain:

from langchain.tools import Tool

# Wrap MCP server function as LangChain tool
mcp_tool = Tool(
    name="mcp_server_query",
    func=mcp_server.query,
    description="Query the MCP server for data"
)

# Add to agent
agent = create_openai_functions_agent(llm, tools=[mcp_tool], prompt=prompt)

With CrewAI:

• Define MCP functions as @tool decorated functions
• Register with specific agents that need MCP access

General principles:

• Always handle MCP server errors gracefully (return error strings, not exceptions)
• Set timeouts on MCP calls (don't let agents hang)
• Log all MCP interactions for debugging

Tool Error Handling Pattern

@tool
def resilient_tool(query: str) -> str:
    """Tool with proper error handling"""
    try:
        result = external_api.call(query, timeout=10)
        return json.dumps(result)
    except TimeoutError:
        return "Error: Request timed out. Please try again."
    except Exception as e:
        logger.error(f"Tool failed: {e}")
        return f"Error: {str(e)}"

Never let tools crash the agent - always return strings, even for errors.

Cost Optimization

Estimation Before Building

Use scripts/cost-estimator.py to estimate costs before implementing:

python scripts/cost-estimator.py --config workflow.json --requests 1000 --optimize

Optimization Strategies

1. Use cheaper models for simple agents:

• GPT-4 for complex reasoning (strategist, analyst)
• GPT-3.5-turbo for simple tasks (formatter, router)

2. Limit iterations strictly:

• Set max_iterations to 5-10 (not 50)
• Set max_execution_time to prevent runaway costs

3. Cache repeated work:

• Enable LLM response caching
• Store results of expensive operations
• Reuse research across similar queries

4. Implement budgets:

cost_tracker = CostTracker()
if cost_tracker.total_cost > budget:
    raise BudgetExceededError()

5. Monitor costs in real-time:

• Track token usage per agent
• Alert when costs approach thresholds
• Analyze cost breakdowns to identify expensive agents

Production Deployment Considerations

Refer to references/production-patterns.md for deployment architectures and references/observability-guide.md for monitoring.

Essential Production Patterns

1. Async Task Queue (Recommended):

• Use Celery + Redis for long-running workflows
• Return task ID immediately, poll for results
• Enables horizontal scaling

2. Always Enable Observability:

• Structured logging (JSON format)
• Distributed tracing (OpenTelemetry or LangSmith)
• Cost tracking per request
• Error monitoring (Sentry)

3. Implement Fault Tolerance:

• Retry with exponential backoff
• Circuit breakers for external APIs
• Graceful degradation (fallback to cheaper models)

4. Security:

• API authentication (JWT tokens)
• Rate limiting (10-100 requests/minute per user)
• Input validation (prevent prompt injection)
• Sandboxed code execution (Docker for AutoGen)

5. Set Hard Limits:

LIMITS = {
    "max_iterations": 10,
    "max_execution_time": 60,  # seconds
    "max_cost_per_request": 1.0,  # USD
    "max_concurrent_agents": 5
}

Anti-Patterns to Avoid

❌ Over-Engineering with Agents

Problem: Using multiple agents when a single LLM call would suffice

Example:

# ❌ Overkill for simple task
agents = [InputParser(), Processor(), OutputFormatter()]
# Just to format text!

Solution: Start simple. One LLM call. Add agents only when truly beneficial.

❌ No Termination Conditions

Problem: Agents run forever or hit arbitrary iteration limits

Solution:

# ✅ Always set termination conditions
max_iterations=10
is_termination_msg=lambda msg: "TERMINATE" in msg.get("content", "")

❌ Vague Agent Roles

Problem: Agents with unclear responsibilities cause overlap and confusion

Solution: Specific roles with clear boundaries. "Senior Python Developer" not "Helper".

❌ Ignoring Costs

Problem: Running expensive models without tracking or budgets

Solution: Track costs per request, set budgets, alert on anomalies

❌ No Observability

Problem: Can't debug when things go wrong

Solution: Implement logging, tracing, and metrics from day one

When NOT to Use Agents

Recognize situations where agents add unnecessary complexity:

Use a single LLM call instead of agents when:

• Task is straightforward (translation, summarization, Q&A)
• No tool usage required
• Single-step reasoning suffices
• Cost and latency must be minimized

Example decision:

• "Translate this text" → Single LLM call
• "Research 10 sources and synthesize findings" → Multi-agent system

Resource Reference Guide

This skill includes comprehensive reference materials. Load them as needed:

Framework Comparisons

• references/framework-comparison.md - Detailed CrewAI vs LangChain vs AutoGen comparison with migration paths

Framework-Specific Patterns

• references/crewai-patterns.md - Role design, task patterns, processes, production tips
• references/langchain-patterns.md - LCEL chains, RAG patterns, LangGraph workflows
• references/autogen-patterns.md - Conversational agents, group chats, code execution

Advanced Topics

• references/custom-agent-guide.md - Building agents from scratch, minimal implementations
• references/observability-guide.md - Tracing, logging, metrics, debugging tools
• references/production-patterns.md - Deployment architectures, scaling, security, monitoring

Helper Scripts

• scripts/cost-estimator.py - Estimate workflow costs before building
• scripts/agent-debugger.py - Analyze traces to identify loops and bottlenecks
• scripts/agent-system-template/ - Boilerplate for new agent systems

Getting Started Workflow

For new agent system development:

1. Validate need for agents - Can this be solved with a single LLM call?
2. Choose framework - Use decision tree above
3. Estimate costs - Run cost-estimator.py with expected workflow
4. Implement with observability - Enable logging/tracing from start
5. Test for loops - Use agent-debugger.py on traces
6. Set hard limits - max_iterations, budgets, timeouts
7. Monitor in production - Track costs, errors, performance

Framework-Specific Quick References

CrewAI Essentials

• Agents need: role, goal, backstory, tools
• Tasks need: description, expected_output, agent
• Processes: Sequential (linear) or Hierarchical (manager delegates)
• Limit: 2-5 agents per crew

LangChain Essentials

• Always set max_iterations on AgentExecutor
• Use LCEL for chain composition: prompt | model | parser
• Enable LangSmith for production: LANGCHAIN_TRACING_V2=true
• RAG: Use RetrievalQA or ConversationalRetrievalChain

AutoGen Essentials

• UserProxyAgent executes code, AssistantAgent generates it
• Always use Docker in production: use_docker=True
• GroupChat needs max_round limit
• Human input modes: NEVER (autonomous), TERMINATE (confirm end), ALWAYS (every step)

LangGraph Essentials

• Define state, nodes (functions), and edges (transitions)
• Use conditional edges for branching logic
• Supports cycles (retries, loops)
• Requires StateGraph setup and compilation

Summary

Multi-agent systems add complexity. Use this skill to:

✅ Make informed framework selections ✅ Design effective agent architectures ✅ Avoid common pitfalls (loops, runaway costs) ✅ Implement production-ready observability ✅ Recognize when agents are overkill

Prioritize simplicity. Start with the minimum viable agent system. Add complexity only when justified by concrete benefits.

Source: shengdabai/Tony-Claude-Code-Skills — distributed by TomeVault.