Sometimes when you write an offer, listing agents (representing the seller) will ask for things like "proof of closing funds" which in other words is usually a copy of your bank statement (with blacked out account numbers and personal information of course!) showing proof of things like your down payment and/or your closing fees. Also, they may ask for a copy of your credit scores - again with blacked out information.
All of these things are to benefit you as a buyer, however I suggest you find an agent you are confident in and feel comfortable providing them with that information if were to find something you wanted to write an offer on.
Hope this helps!
1) how you plan to finance the purchase - will it be all cash, will it be 20% down with an 80% mortgage, will it be 5% down with a 95% mortgage, etc. and what do you have to prove you can bring the necessary cash to closing
2) whether you have the funds to cover the closing costs (if not, then maybe have to negotiate for them and could effect what day in the month you want to close);
3) what purchase price you are comfortable purchasing and whether you can qualify for the necessary financing at that price (why look at homes you are not going to want to purchase and may not be able to afford);
4) whether you have and can provide the necessary funds to cover the typical earnest money requirement for the price range you are looking to purchase plus the other cash up front expenses (inspection fees, sometimes lender fees like appriasal and credit report); and
5) what the "ballpark" credit scores are and whether there have been items in the past that may reduce the mortgage options available to you as a Buyer, or affect the interest rate you may need to pay.
I also think it is helpful for the loan officer and Realtor to visit in advance of any offer being submitted especially if it will be a quick closing or if the mortgage options are limited (typically due to lower credit scores) - I think the better the communication between the triangle of the Realtor, the Loan Officer, and the Buyer, the fewer surprises will occur and the greater the likelihood of the closing occurring in a smooth manner.
I don't think items such as income, other assets, other debts, etc are items the agent needs to know assuming you have been pre-approved for the financing. Best of luck in your search.