So let's sum things up: The LOI and similar documentary terms, are non standard, confusing, and lead to ambiguity. Documentary ambiguity is referred to in trade law as a condition "The Battle of the Forms" in which confusion from contradictory and ambiguous forms and documents damages the transaction. This should be avoided. To seasoned corporate traders and bankers, using terms like "Letter of Intent" is the mark of amateurs. What you properly want is an RFQ, request for quotation, from a seller or supplier. The seller may then reply to your RFQ with a quote OR full offer if they wish.
So you see, the response requested is indicated in the very form and name of the document itself. The Letter of Intent has no established place in International trade law. Where they are used _ rarely _ is in some small niche internal markets and trades. The RFQ, Request for Quotation, a standard protocol in the business world, is what most brokers actually want when they err in using an LOI.