Suppose I want to use a CLI tool which was previously built using python, and I don't have python installed on my system. Am I still able to use that CLI tool ? (without installing python). If yes, then how it made to work ? Will it be same if tool was built using other ways instead of python ?
Generally, if it is interpreted then you will need the language on the system (or like Java, which needs a runtime installed).
There are tools available to produce an executable for Python, so it doesn't need to be ran with python main.py, for example PyInstaller.
If the tool/program was compiled into a binary blob, like how C/C++ compiles to a binary executable, it can be used without the libraries/language used to build it.