<div id="imageEditor"></div>
<script>
$("#imageEditor").kendoImageEditor({
    toolbar: {
        items: [
            { 
                text: "Custom Button", 
                attributes: { 
                    "data-role": "custom-tool",
                    "title": "Custom tooltip",
                    "class": "my-custom-class"
                },
                click: function() { console.log("Custom button clicked"); }
            }
        ]
    }
});
</script>