conda-auto-env | Automatically activate a conda environment | Reinforcement Learning library

It should be possible. Inspired by this line in the fish documentation (emphasis mine):

Autoloading Functions

When fish encounters a command, it attempts to autoload a function for that command, by looking for a file with the name of that command in ~/.config/fish/functions/.

So we can have a function that checks the folder on every 'cd' command and run the script to activate where appropriate. Easier to do it if you have only one VE.

May be the solution is to check for a certain script file that switches the VE in the new directory and execute it if it exists. (That has to take care of how to handle the case where you switch directly to a subdirectory.)

Updated after a counter question from the OP: Here is what I had in mind. Say we copy this function to a file called ~/.config/fish/functions/cd.fish: