Chocolate syrup, refined sugar free

I invented this recipe a few years ago, as my husband really likes his chocolate milk, but reading on the back of ready made chocolate milk I found them to be filled with a lot of sugar and other not so good for you things. So I looked on the internet to figure out how to make my own chocolate milk and the easies way it seems, was by using a chocolate syrup. So I started experimenting with some recipes, to make one without white sugar and this is the end result.
My husband loves this syrup, he actually says it taste a lot like his favourite chocolate milk when added in milk. But it can also be used on other things, like on ice cream, desserts or even a teaspoon in coffee to make a mochaccino. 

½ cup pure cocoa powder
½ cup water
½ cup agave or sweet freedom
1/8 teaspoon salt
1 teaspoon vanilla paste

In a small pot mix the cocoa powder, water and salt together and bring to a boil. Whisk until there are no lumps.
Ad the agave or sweet freedom, and boil until it stars to thicken a bit (like syrup).
Take off the heat and stir in the vanilla extract.
Let it cool for a bit, then transferee to container of choice (I used an empty agave bottle that I had cleaned, as it makes it easy to dispense).
Store in the fridge for about a week and give it a little shake before use.