AW yes.... Gods love

[Faith No More]

The question isn't about interpreting the Bible, but examining its trustworthiness.

Now you're splitting hairs. To examine the bible's trustworthiness is to interpret it.

Take for example the claims that the Bible makes about metaphysics, and someone who holds to metaphysical skepticism. It would be circular for that person to apply their belief that metaphysical skepticism is true to say "We cannot trust the claims the Bible makes about metaphysics, because metaphysical skepticism is true."

If one believes in metaphysical skepticism why should they set that aside to interpret the bible? Anyone who subscribes to such philosophy can interpret the validity of the bible based on their views of the metaphysical. To say otherwise is to determine only your metaphysical view is the correct way to interpret the bible. This is besides the point, however, as this was your original claim...

Metaphysical skepticism is inconsistent with the Bible (which, for example, teaches that God reveals knowledge about Himself (e.g. Psalm 19), and so to apply metaphysical skepticism in order to argue that the Bible should not be trusted is applying circular reasoning.

You are saying, possibly inadvertently, that you cannot apply metaphsycial skepticism to the bible because the bible says God reveals knowledge of himself. This is interpreting the bible by assuming what the bible says is true.

That's because it assumes the falsity of the Biblical view that metaphysical knowledge is possible. It's just a simple example of the kind of circular reasoning that can occur. It also applies equally to the person wishing to defend the Bible, who might assume an Biblical epistemological principle in order to defend the Bible.

Assumptions have to be made to interpret the bible. Just because the assumptions are inconsistent with what the bible says, is in no way circular. When interpreting the bible, it is not circular to assume metaphyscial knowledge is possible based upon your own experiences but to assume metaphysical knowledge is possible, simply because the bible says so is circular.