Create this test template in lib/templates/test.mustache {{! @template core/test Testing template. Example context (json): { "messa"ge": "Your pants are on fire!" } }} <div class="alert alert-success">{{{message}}}</div> Set Site admin -> Development -> Debugging -> Debug messages to ' Developer '. Note: You can instead run mdk run mindev if you use mdk Open the developer tools in your browser (Hit F12, or right click => inspect element) View the "Console" Go to Site admin -> Development -> Template Library admin tool Search for the " test " template Select the template Confirm that you see "{{Could not parse json example context for template.{{" with a stack trace etc. Set Site admin -> Development -> Debugging -> Debug messages to ' None '. Note: You can instead run mdk run undev if you use mdk Go to Site admin -> Development -> Template Library admin tool Search for the " test " template Select the template Confirm that you do not see any new error messages in the Developer tools console