Adding a input context can be done fairly easy using something like:

// Ensures that the module is loaded before trying to access an
// instance.
mw.loader.using( [ 'ext.smw.suggester' ], function() {

    var context = $( '#someElement > input' );

    if ( context.length ) {

        var entitySuggester = smw.Factory.newEntitySuggester(
            context
        );

        // Register default tokens
        entitySuggester.registerDefaultTokenList(
            [
                'property',
                'concept',
                'category'
            ]
        );
    };
} );

Register an additional token

It may be desired to define additional tokens that active a suggestion request.

mw.loader.using( [ 'ext.smw.suggester' ], function() {

    var context = $( '#someElement > input' );

    if ( context.length ) {

        var entitySuggester = smw.Factory.newEntitySuggester(
            context
        );

        // Register default tokens
        entitySuggester.registerDefaultTokenList(
            [
                'property',
                'concept',
                'category'
            ]
        );

        entitySuggester.registerTokenDefinition(
            'property',
            {
                token: '?p:',
                beforeInsert: function( token, value ) {
                    return value.replace( 'p:', '' );
                }
            }
        );
    };
} );