from pydantic import BaseModel
    from praisonaiagents.agent.handoff import TypedHandoff, HandoffValidationError
    
    class ResearchResult(BaseModel):
        summary: str
        citations: list[str] 
        confidence: float
        
    # Create typed handoff
    typed_handoff = TypedHandoff(
        agent=writer_agent,
        input_schema=ResearchResult
    )
    
    # Valid payload
    result = ResearchResult(
        summary="AI research findings", 
        citations=["ref1", "ref2"], 
        confidence=0.92
    )
    response = typed_handoff.execute_programmatic(source_agent, result)
    
    # Invalid payload raises HandoffValidationError
    bad_payload = {"summary": "...", "citations": "not-a-list"}
    typed_handoff.execute_programmatic(source_agent, bad_payload)  # Raises error