“I got you” typed in a chat is still a contract. Screenshots are forever.

A promise made casually is still a promise, and the casualness is mostly on your side rather than theirs. The other person made plans around it. Putting it in writing only makes the distance between what you said and what you did easier to see afterward. Keeping small commitments is what makes the large ones believable.

Before typing an agreement, take the second it costs to check whether you will really do it. If you cannot, say so straight away rather than quietly hoping it fades. A quick no is worth far more than a slow disappearance.