- Add allowed_agents field to BaseAgent class with validation
- Modify AgentTools to filter delegation targets based on allowed_agents
- Update Agent.get_delegation_tools to pass delegating agent context
- Support both role strings and agent instances in allowed_agents
- Implement case-insensitive role matching for flexibility
- Add comprehensive test coverage for all scenarios
- Maintain backward compatibility (None = allow all agents)
- Handle edge cases (empty list = no delegation allowed)
Addresses issue #2068 for controlled hierarchical delegation
Co-Authored-By: João <joao@crewai.com>
