A while ago I was given a free spell from my benevolent GM, and I chose Armor of Agathys with the caveat that I could change the damage type (let's leave aside the balance concerns of that for now) and name (to that of my character's patron).
I managed to find the what was claimed to be 'best' way to achieve this, via the D&D Beyond forums was to create a feat that granted a free spell, and I created that (named 'Blessing of the Draumrsteig') and my custom spell. I can't remember the forum post, otherwise I'd share it here.
Unfortunately I can't make the feat public:
This homebrew Feat has data mapped to it that is licensed content or private homebrew. This typically occurs when licensed or private homebrew spells are linked to the Feat.
I did have a link to my homebrew spell but that's also been marked as too small a variation to be shared.
What I have noticed is that I can't get it to scale like Armor of Agathys does. And I'm not sure how to do that either (I'm also not certain what I've done to get to this stage, so bear with me if my details are off). It's showing the spell as 'at will' which I think is a concession from advice I found on the DnDBeyond forum...?
This is how it appears:
As you can see the effect only shows the number 5 and a heart symbol, and hasn't scaled with my pact slot level.
How can I achieve this scaling effect on temporary HP and damage?