It seems unremarkable that Catholic catechisms profess the inerrancy and essentiality of the entirety of Catholic doctrine. What is less clear is why I should simply take the Catholic church’s word for it ... regardless of whether those words are in catechisms or not.
Citing Catholic writings as proof of the inerrancy of Catholic writings creates something of a feedback loop.
SnakeDoc
Previously Radio Replies has given purely historical evidence as to why the Catholic church is believed to be the true doctrinally inerrant body esablished by Christ.