There are a lot of very important items in these documents and you do not want to make a mistake here. This begs the question, "What is the most important clause to include in a purchase agreement or letter of intent?"
The second important element is to clearly state the intended parties outcome from the disclosure. In the example above the intended outcome could be "The information is being disclosed to assess whether XYZ transportation company will pilot the software for use within its fleet". Again it is then clear what the outcome and the nature of the relationship will be. The example above is broad enough to allow some flexibility in discussion in the letter of intent e.g. that perhaps the pilot programme is limited to one territory as negotiations progress, but it must be narrow enough that the outcome is reasonably well known e.g. it is not expected that XYZ transportation become a shareholder in the software company.