[muizelaar]

How does it compare to mathics?

How close is it to being able to run rubi: https://rulebasedintegration.org/?

[disentanglement]

You can find the whole integration routine here https://github.com/ad-si/Woxi/blob/36343ab2cbc97e5081f7c811e.... It's essentially a test mock-up (not even trying partial fraction decomposition for rational functions).

[anematode]

    // ∫ tan(x) dx = -ln|cos(x)| - not implemented (requires Log)

This really doesn't bode well... I'm no expert in CASes, but everything I've looked at seems very naive. Vibe coding a Mathematica replacement makes zero sense to me.