This is the only prayer to Agathos Daimon. It comes from the book ‘In Praise of Olympus: Prayers to the Greek Gods’ by Hearthstone. Hope that you can use it and enjoy it.
I call to you for favor, my own good spirit, my Agathos Daemon, my companion through life.
From the day of my birth you have walked next to me, turned me from all evil, kept me safe from those who would do me harm.
In days of old, kind spirit, you received offerings of strong wine, you were honored at great banquets and in the home.
Faithful one, unfailing guardian of my luck, I turn to you for counsel when I am in doubt, for direction when I am uncertain.
Mild and helpful spirit, I thank you for your guidance, I thank you for your blessings.
Agathos Daimon, I honor you.