There are many rationality meanings.
Theoretical rationality applies to beliefs.A belief is rational if it is supported by reasons and, in particular, reasons that render this belief likely to be true. Equally a belief is rational if it is produced by reliable methods, that is, methods that tend to produce true beliefs. As Robert Nozick put it, reasons without reliability seem empty and reliability without reasons seems blind.
The rationality of action, practical rationality, is taken to be a means-end issue: rational action consists in following the best strategy that will promote one’s aims. Rationality thus becomes goal directed, but the goals themselves are typically taken to be beyond rational adjudication. This purely instrumental conception of rationality can also be attributed to the rationality of belief. Therefore certain emotions can be practical rationality, that is, certain emotions can lead to optimal outcomes in the appropriate situation. It is not necessary to expanding the definition of rationality in philosophy to include optimal behavior, it is already part of a definition of rationality.
In other words, the concept of practical rationality, whether pertaining to decisions, strategies, intentions, beliefs, or still something else, essentially involves the notion of a goal. To say that a belief or emotion is rational, then, is to say that the belief or emotion will contribute to the achievement of a particular goal. And to say that a belief or emotion is irrational is to say that the belief or emotion will not contribute to the achievement of a particular goal. When it comes to rationality of beliefs, the goals will obviously be intellectual ones, then it may be said that the goal to which a rational belief is directed is truth, or some other cognitive virtue.
There is a sense in which the rationality of a belief is not an instrumental property of this belief. Rather it is a function of the epistemic relation between the evidence and the belief for which it is taken to be evidence, and hence a function of the soundness of the methods that produced and sustain these beliefs.