20. The system as recited in claim 17 , where in the engine pool is located at a client device where the query is received and the first set of input candidates and the second set of input candidates are presented.
17. A system comprising: memory storing one or more modules; one or more processors operably coupled to the memory to execute the one or more modules, the one or more modules including: a user interface of an IME that receives a query from a user; a collection component that collects data, the data comprising: first data relating to a first scenario of a first computer application to which the user is to input one or more input candidates, a first context of the query in view of contents displayed at a first user interface of the first computer application, second data relating to a second scenario of a second computer application to which the user is to input one or more input candidates, and a second context of the query in view of contents displayed at a second user interface of the second computer application; an analysis component that analyzes the collected data to determine scores for different types of input candidates, each score indicating a likelihood that a rich candidate is associated with the first context or the second context, and to determine, based in part on the scores: a desired first type of input candidate to request in association with the first computer application, and a desired second type of input candidate to request in association with the second computer application, the desired first type of input candidate being one of a text candidate or a rich candidate; a selection component that selects: a first scenario-tuned and type-specific input candidate engine from an engine pool based on the query, the first scenario, and the determined first desired type of input candidate to identify a first set of input candidates, and a second scenario-tuned and type-specific input candidate engine from an engine pool based on the query, the second scenario, and the determined second desired type of input candidate to identify a second set of input candidates; and a presentation component that: displays the first set of input candidates at the user interface of the IME, receives a first selection of at least a first input candidate of the first set of input candidates, based at least in part on the first selection, transmits the first input candidate to a first user interface of the first computer application, the user interface of the IME being separate from the first user interface of the first computer application, displays the second set of input candidates at the user interface of the IME, wherein at least one input candidate of the second set of input candidates is not included in the first set of input candidates, receives a second selection of at least a second input candidate of the second set of input candidates, and based at least in part on the second selection, transmits the second input candidate to a second user interface of the second computer application, the user interface of the IME being separate from the second user interface of the second computer application.