Currently if you add a field in the fields parameter with a wildcard, no fields will be added to the hits layer. The situation is even worst if the wildcard matches the field name of the geo_point or geo_shape field, in that case a ClassCastException is thrown.
x-pack/plugin/vector-tile/src/javaRestTest/java/org/elasticsearch/xpack/vectortile/VectorTileRestIT.java
final VectorTile.Tile tile = execute(mvtRequest);
        assertThat(tile.getLayersCount(), Matchers.equalTo(2));
        assertLayer(tile, HITS_LAYER, 4096, 33, 2);
        assertLayer(tile, META_LAYER, 4096, 1, 8);
    }
    public void testNoAggLayerURL() throws Exception {
        final Request mvtRequest = new Request(
            getHttpMethod(),
            INDEX_POINTS + "/_mvt/location/" + z + "/" + x + "/" + y + "?grid_precision=" + 0
        );
        mvtRequest.setJsonEntity("{\"size\" : 100, \"grid_precision\": 4 }");
        final VectorTile.Tile tile = execute(mvtRequest);
        assertThat(tile.getLayersCount(), Matchers.equalTo(2));
        assertLayer(tile, HITS_LAYER, 4096, 33, 2);
        assertLayer(tile, META_LAYER, 4096, 1, 8);
    }
    public void testNoHitsLayer() throws Exception {
        final Request mvtRequest = new Request(getHttpMethod(), INDEX_POINTS + "/_mvt/location/" + z + "/" + x + "/" + y);
        mvtRequest.setJsonEntity("{\"size\": 0 }");
        final VectorTile.Tile tile = execute(mvtRequest);
        assertThat(tile.getLayersCount(), Matchers.equalTo(2));
        assertLayer(tile, AGGS_LAYER, 4096, 1, 2);
        assertLayer(tile, META_LAYER, 4096, 1, 13);
    }
    public void testNoHitsLayerURL() throws Exception {
        final Request mvtRequest = new Request(getHttpMethod(), INDEX_POINTS + "/_mvt/location/" + z + "/" + x + "/" + y + "?size=" + 0);
        mvtRequest.setJsonEntity("{\"size\": 100 }");
        final VectorTile.Tile tile = execute(mvtRequest);
        assertThat(tile.getLayersCount(), Matchers.equalTo(2));
        assertLayer(tile, AGGS_LAYER, 4096, 1, 2);