1. A method comprising: when a multimodal interface of an electronic device is at a first modality, determining that a context of the electronic device satisfies a criterion, wherein determining that the context of the electronic device satisfies the criterion is based on one or more signals from a sensor of the electronic device, and wherein the sensor is in addition to a microphone of the electronic device; and by the electronic device, and responsive to determining that the context of the electronic device satisfies the criterion: preemptively establishing a session between the electronic device and a query processor configured to process input received at a second modality of the multimodal interface; receiving second modality input at the second modality of the multimodal interface; initiating processing of at least a portion of the second modality input at the query processor within the session; and building a complete query based on output from the query processor.