Rinse and dry the grapes. Remove stems and halve any large ones.
Beat cream cheese in a large bowl until smooth and fluffy.
Whisk in sour cream, granulated sugar, vanilla, lemon juice, and salt until creamy.
Fold the grapes into the dressing, gently coating them all over.
Spread into a serving dish. Sprinkle brown sugar evenly, then add pecans on top.
Chill 20–30 minutes, if time allows, to set and meld flavors.