This outcome is probably the best that markets can hope for. Trump has been able to hold oil prices down just by saying 39 times there would be a deal. Diplomacy with Iran is slow, technical, painful, and they tend to outfox their opposite number, but in the very short term opening the strait to traffic is what the market wants to see.
For the first time, Trump announced a deal was imminent and the Iranian state news agency didn't contradict him.