The generator defined so far will generate sentences with logical forms that are compatible with the input logical form. It is possible to define a stricter generator that will only generate sentences whose logical form subsumes the input logical form (coherence) and is subsumed by the input logical form (completeness). For a discussion see .
The generator as it stands may be rather non-deterministic with respect to the particular choice of the inflectional form of lexical entries. For example the agreement features of a verb may only be known after the generation of the subject. Some uninteresting non-determinism can be eliminated by postponing this choice to a postprocess. Instead of yielding a string the generator will yield a list of lexical entries for which inflectional rules select the apropriate form. For more details see .
It is also possible to allow for extra predicates in rules. For example in  this possibility is used to implement quantifier storage. In general there may be some problems with this technique as the order of selection of literals is different than in the usual top-down case. Again delayed evaluation techniques will prove useful here.