"Maybe there's some way to make a magic-o-meter. It'd be handy, that's for sure... Gonna try something."

Deep breath.

"Oh bright westward sun and clear eastward moon! Reveal to my sight the kind and measure of the magic around me!"

It works! And it works very similarly to him just meditating, except it's an overlay to what his eyes are seeing. He can see Sadde and Kero's magic, of a similar not-quite-color that's not-quite-golden, and he can see how Kero has much more of it than Sadde.

"Cool, I can see magic without having to meditate. Sadde, do something small, quick, dunno how long it'll last."

Sadde casts the crappiest flight spell.

The magic Terry can see doesn't change in the slightest.

"...Uh, nothing changed. Something bigger?"

Better flight spell!

Doesn't change either.

And then Terry's spell runs out.

"So that was probably showing me your total strength not what was being actually used. You think a different phrasing can reveal active magic?"

"Maybe? It's kinda hard to predict, with a system like this."

"Nothing except to try it? It's kind of exciting if it weren't so confusing."

"I mean, I think it's exciting even though it's confusing, so."

"We'll just have to spend all day doing experiments, figuring this out. Unless a card shows up or something, which means I should probably meditate to check every few hours."

"Yeah. It looks like each time I cast a spell it adds less to the max so we could see if it ever stops and then do the thing you suggested about counting how many times we can cast a given simple spell or write a small scroll before running out..."

"I think we can explore what kind of variety we can get and how different combinations affect the results for a while first. It's more interesting too."

"But then it'll be harder to figure out how much each spell adds to the max exactly."

"Is that the most useful thing to know compared to getting an idea of our capabilities and the general behavior? I kind of doubt it, it's a slightly longer term project to figure out how magic power levels work I think."

"Yeah I suppose you have a point. We can probably start from the list of cards, everything they can do sorcery probably can, too."

"Well, I still have my card list. Glow, float, windy, flower, loop, change, sword, fight, dash off the top of my head..." He grabs his backpack and starts digging through it.

"There were the elements, light and dark, time..."

And he reads off the rest of the list, and starts marking down things they know sorcery can do already.

Elemental manipulation. Arbitrary (if temporary) matter generation. Specific permanent matter generation. Time shenanigans. Space shenanigans. Absolute destruction. Very specific things like locking doors or cutting things or running fast or shielding. Changing physical states. Changing things in general. Illusions. Dream manipulation. Truth-detection. Sound and light manipulation.

He marks off which cards are already covered in their known-possible-things list and starts trying the easiest-seeming ones. Like flower.

"By the power of the sun and the breath of the earth, I call forth a flower, summon rose!"

He now has: a rose.

He presents the rose to Sadde with a little bow, looking like he's trying not to laugh.

Sadde grins and accepts. "Why, thank you."

"My pleasure."

Checkbox: Marked.

Next up: The Dash.

And so on, skipping the ones Kero says are power-intensive like Time entirely.