Variable WHITEBOARD_WIDGET_STARTER_HTMLConst
WHITEBOARD_WIDGET_STARTER_HTML: "<!doctype html>\n<html>\n<head>\n<style>\n body { font-family: system-ui, sans-serif; margin: 14px; color: #1f2937; }\n h3 { margin: 0 0 6px; }\n label { display: block; margin: 4px 0; }\n button { margin-top: 8px; padding: 5px 12px; border: 1px solid #cbd5e1; border-radius: 6px; background: #f1f5f9; cursor: pointer; }\n .hint { margin-top: 8px; color: #6b7280; font-size: 12px; }\n</style>\n</head>\n<body>\n<h3>Quick quiz</h3>\n<p>Which planet is closest to the sun?</p>\n<label><input type=\"radio\" name=\"q\" value=\"Mercury\"> Mercury</label>\n<label><input type=\"radio\" name=\"q\" value=\"Venus\"> Venus</label>\n<label><input type=\"radio\" name=\"q\" value=\"Mars\"> Mars</label>\n<button id=\"go\">Submit answer</button>\n<p class=\"hint\">Submitting sends your answer to the agent via MJWhiteboard.submit.</p>\n<script>\n document.getElementById('go').addEventListener('click', function () {\n var picked = document.querySelector('input[name=\"q\"]:checked');\n MJWhiteboard.submit({ question: 'closest planet to the sun', answer: picked ? picked.value : null });\n });\n</script>\n</body>\n</html>" = ...
Starter document placed by the HTML-widget tool (user click-place) — a one-question quiz that demos the
MJWhiteboard.submitinput bridge: the Submit button posts the picked answer to the host, which surfaces it to the session agent as a context note. (Hardcoded colors are fine here: this is an isolated sandboxed document — the app's design tokens cannot reach inside the opaque-origin frame.)