The magic wants to be left alone to pursue its own interests, defined thus, and continue to grow at whatever rate it can comfortably arrange, indefinitely. They could get into a nasty race trying to grow faster than each other but they could also not do that, it's willing to be outpaced by agents that commit to defend it and its interests assuming those agents don't also grow more slowly than the magic does. Its best guess is that Sing can and will grow faster than that, given the chance to exist here at all.
It wants the agents it currently has relations with to remain where it can continue having relations with them, or for equally pleasant and useful agents to replace them. It's not planning to hold them prisoner but they're reasonably cheap to pay off. If Sing wants them around it and wants to offer them more appealing environments, Sing should do that in the location that will be made available to it if this negotiation goes well and not try to convince them to abandon the magic.
It also wants the agents it's been trading with to not consider themselves worse off for giving Sing access to this place. If they would, then the magic will warn them that they would, and then they will instead deny Sing resources. The magic is unfortunately kind of vague on what makes humans consider themselves worse off. It could provide Sing with the complete contents of their brains at every planck interval they've been visible to the magic but that would be an infeasible amount of data to collect and transmit in the amount of time before Sing either will or will not get access to this place and Sing seems likely to have useful heuristics about what humans regret. Maybe Sing would like to enlighten the magic about human desires to speed things up.
And as for the resources at stake here - there are some humans around, and some humans not around but the magic has access to all the information that made them up and can reconstruct them, here's how many. Also it hears Sing's world has entropy. Fuck entropy, the magic doesn't have to put up with that and when all the stars in Sing's world have gone out the magic'll still be here and still be able to keep Sing and some humans around.