Filter out LLM request when switching between agents

[dipayandev]

** Please make sure you read the contribution guide and file the issues in the right place. **
Contribution guide.
Is your feature request related to a problem? Please describe.
Currently the LLM calls include all history from the session. We have a specific use case filter out the LLM request when switching between agents
Describe the solution you'd like
Create a tool for the same. The same will be called using before_model_callback
Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.
Additional context
I have written a tool for the same, happy to contribute

[hangfei]

this is supported. convert to Q&A