Place berries, agave nectar, and water in a medium saucepan. Bring to a simmer over medium-high heat. Reduce heat to low and simmer an additional 10 minutes or until berries have softened and mostly burst.
Very carefully (it’s hot!) pour the berry mixture into a blender, and pulse a few times until smooth.
Pour blended mixture through a mesh strainer to remove seeds if desired. (I left the seeds in.) Serve immediately warm as a topping for waffles or pancakes. Store in a covered container in the refrigerator up to two weeks for other uses.