I alluded to this previously, but I don't see how any "verbal agreement" reached at the performance review Trump-Putin meeting in Helsinki could possibly be characterized as an "agreement" in the sense of being a binding commitment of the U.S. We have little idea of what Putin and Trump discussed. Unless the translator does testify (and I doubt that she will), all we have are the self-serving statements of two liars.
In order for the U.S. to abide by any agreement, people other than Trump would have to do things to carry it out. While Putin can simply order his government to do whatever is needed without further explanation, Trump's orders will be questioned and possibly legally challenged, especially if it is something out of the ordinary that he has never talked about doing before. So if he does try to, for example, turn over former ambassador to Russia Michael McFaul to be questioned by Russian authorities, there would be political blowback and McFaul himself could fight it in the courts. Maybe Putin does not understand the limits of what Trump can actually commit to in a one-on-one exchange. Trump might not either.
In order for the U.S. to abide by any agreement, people other than Trump would have to do things to carry it out. While Putin can simply order his government to do whatever is needed without further explanation, Trump's orders will be questioned and possibly legally challenged, especially if it is something out of the ordinary that he has never talked about doing before. So if he does try to, for example, turn over former ambassador to Russia Michael McFaul to be questioned by Russian authorities, there would be political blowback and McFaul himself could fight it in the courts. Maybe Putin does not understand the limits of what Trump can actually commit to in a one-on-one exchange. Trump might not either.