** Please make sure you read the contribution guide and file the issues in the rigth place. **
Contribution guide.

Is your feature request related to a problem? Please describe.
We are currently adapting our project to ADK.

When I want to search for historical records, such as the project we discussed last week. The document can only be used from memory or vertex AI. And the Rag function requires us to build additional agents. I hope we can expose these interfaces so that we don't have to rely too much on Google Cloud because it's not very convenient for us, although I also want to use the services provided by Google. ADK is a very strong project, I really appreciate it. If possible, I could do it this way

Describe the solution you'd like
Compatible with other vector databases such as milvus. Support loading chat records from the database and querying them directly from the chat records