Designer’s glossary: A+B mechanics
A+B mechanics also enabler-payoff mechanics
/ eɪ plʌs biː /
A+B mechanics are mechanics which are made of 2 distinct and separate parts, namely the enabler (A) and payoff (B). These mechanics require both parts to be combined to have any meaningful effect or benefit.
Now, A+B is mostly a sliding scale, i.e. the individual usefulness of the two parts can vary, however in the general sense, it’s necessary for both parts to work together for the mechanic to do anything, i.e. do B, only if you have A/only if you’ve already done A.
While conditionals are the most common form of A+B, it’s not the only way of doing this kind of mechanic. For example, sometimes the payoff gets a smooth-scaling boost in power depending on the amount of setup (resources or previous effects) you’ve done using the enablers.
Antonym: self-enabling mechanics
The enabler pretty much always has value by itself, so it’s often perfectly fine to use in isolation. However, that is not usually the case for the payoff, which needs the setup that the enablers provide, and lacking that it either does very little, or in some cases, nothing at all. The key thing with designing A+B mechanics is to be aware of the ease of use of each individual part, as well as the availability. As an example, in card games, the player is going to have a bad time if they have a payoff card in their hand that they can’t make good use of because they didn’t draw any enablers, or vice versa—having all the enablers but not being able to ‘cash in’ the reward from any payoffs.
Sometimes, an A+B-ness of a mechanic can be mitigated by making more enablers. This doesn’t necessarily mean just having a greater number of enabler pieces (which works, but is more a patch fix), but rather generalizing the payoff to be able to work with a wider array of enabler effects. To put it in other terms, you would take the A+B and turn it into something like (A OR B) + C. Do keep in mind that over-generalizing a payoff can backfire, since it would no longer feel special or worth pursuing if you can get it through doing pretty much anything in the game.