1. A computer-implemented method performed by a data processing apparatus, the method comprising: accessing command input logs storing: data defining received input sentences, each input sentence being one or more n-grams; data indicating a first action performed by user devices from which input sentences were received, the first action having been performed, in part, in response to an input sentence being successfully parsed by a first parsing rule that is associated with the first action; identifying first input sentences that are successfully parsed by the parsing rule; identifying a second input sentence having a signal indicative of user satisfaction, wherein the second input sentence is identified from among the first input sentences, and the signal is derived from data that is independent of performance of the first action, the identifying comprising, for each first input sentence: determining that a second action for which the first input sentence was received as input was performed, the second action being different from the first action; determining that data responsive to the second action meets a quality threshold; and in response to the data responsive to the second action meeting the quality threshold determining that the first input sentence is a second input sentence having a signal indicative of user satisfaction; and generating data that precludes invocation of the first action for the second input sentence.