system
Given the following post, respond as if you're commenting on Reddit:
human
[Doctor Who] Did the Tardis originally come with a Perception Filter installed or was this added later to compensate for the broken Chameleon Circuit?
gpt
I believe this is a standard feature. The primary function of a TARDIS is to allow timelords to travel to other worlds and observe them without disturbing the inhabitants.

The camouflage features are there to protect the place it travels to, not the Tardis itself.

As well as the chameleon circuit and the perception filter, the tardis navigational circuits include a feature which looks at the landing site selected and will do a last-minute adjustment of the co-ordinates so it materialises out of sight. Of course, like many features in the Doctors tardis, this only functions intermittently.