diff --git a/services/minecraft/src/debug/web/app.js b/services/minecraft/src/debug/web/app.js
index 8d86c804b..b795b06e3 100644
--- a/services/minecraft/src/debug/web/app.js
+++ b/services/minecraft/src/debug/web/app.js
@@ -24,9 +24,14 @@ const SYSTEM_STATE_MARKER = 'The following blackboard provides you with informat
 // =============================================================================
 
 function escapeHtml(text) {
-  const div = document.createElement('div')
-  div.textContent = text
-  return div.innerHTML
+  if (text == null)
+    return ''
+  return String(text)
+    .replace(/&/g, '&')
+    .replace(/</g, '&lt;')
+    .replace(/>/g, '&gt;')
+    .replace(/"/g, '&quot;')
+    .replace(/'/g, '&#39;')
 }
 
 function formatSystemMessageContent(content) {