The Litany of Tarski (formulated by Eliezer, not Tarski) reads

If the box contains a diamond,

I desire to believe that the box contains a diamond;

If the box does not contain a diamond,

I desire to believe that the box does not contain a diamond;

Let me not become attached to beliefs I may not want.

This works for a physical realist, but I have been feeling uncomfortable with it for some time now. So I have decided to reformulate it in a more instrumental way, replacing existential statements with testable predictions. I had to find a new name for it, so I call it the Litany of Instrumentarski:

If believing that there is a diamond in the box lets me find the diamond in the box,

I desire to believe that there is a diamond in the box;

If believing that there is a diamond in the box leaves me with an empty box,

I desire to believe that there is no diamond in the box;

Let me not become attached to inaccurate beliefs.

Posting it here in a hope that someone else also finds it more palatable and unassuming than straight-up realism. 

EDIT: It seems to me that this modification also guides you to straight-up one-box on Newcomb, where the original one is mired in the EDT vs CDT issues.

EDIT2: Looks like the above version resulting in people confusing desiring accurate beliefs with desiring diamonds. It's about accurate accounting, not about utility of a certain form of crystallized carbon.

Maybe the first line should be modified to something like "If I later find a diamond in the box...", or something. How about the following?

If I will find a diamond in the box,

I desire to believe that I will find a diamond in the box;

If I will find no diamond in the box,

I desire to believe that I will find no diamond in the box;

Let me not become attached to inaccurate beliefs.

For some reason the editor does not let me use the <strike> tag to cross out the previous version, not sure how to work around it.