add used tools to main context window

[nilsherzig]

Is your feature request related to a problem? Please describe.
In response to this question:

Hey I was wondering if it is expected in current version for subsequent identical prompts to trigger another external web search, regardless if the vector DB already has the same pages stored / cached? or if I may have something acting oddly?

Describe the solution you'd like
Adding the tools (and input) used by the other chains in the thread to the main context window would allow new chains (new questions) to get an understanding about the possible state of f.ex. the vector db