I've definitely had agreements like that in the past - the problem is the disconnect between 'this is our intent' and 'this is what the doc says'. As an employ

I've definitely had agreements like that in the past - the problem is the disconnect between 'this is our intent' and 'this is what the doc says'. As an employee, the power/resource imbalance between me and the company means that I wouldn't be willing to undertake the risk of the company not changing their mind about intent. We don't want our employees to have to do the same internal risk analysis as it immediately puts them in an adversarial mindset (how much of a jerk could the company be and get away with it legally, etc). You are right that there are certain things that have to be in there - anything written for a client is owned by the client, etc. Most agreements overreach, though, and ask for everything.