diff --git a/x-pack/plugins/synthetics/public/apps/synthetics/components/monitor_add_edit/form/field_config.tsx b/x-pack/plugins/synthetics/public/apps/synthetics/components/monitor_add_edit/form/field_config.tsx
index d28f8f7f39eb0..6cb68ae27cd7c 100644
--- a/x-pack/plugins/synthetics/public/apps/synthetics/components/monitor_add_edit/form/field_config.tsx
+++ b/x-pack/plugins/synthetics/public/apps/synthetics/components/monitor_add_edit/form/field_config.tsx
@@ -886,8 +886,9 @@ export const FIELD = (readOnly?: boolean): FieldMap => ({
     label: i18n.translate('xpack.synthetics.monitorConfig.params.label', {
       defaultMessage: 'Parameters',
     }),
+    controlled: true,
     component: JSONEditor,
-    props: ({ setValue }): JSONCodeEditorProps => ({
+    props: (): JSONCodeEditorProps => ({
       id: 'syntheticsMonitorConfigParams',
       height: '100px',
       ariaLabel: i18n.translate('xpack.synthetics.monitorConfig.paramsAria.label', {
diff --git a/x-pack/plugins/synthetics/public/apps/synthetics/components/monitor_add_edit/form/form_config.tsx b/x-pack/plugins/synthetics/public/apps/synthetics/components/monitor_add_edit/form/form_config.tsx
index 9c49b0989b5de..f4a099eaa76db 100644
--- a/x-pack/plugins/synthetics/public/apps/synthetics/components/monitor_add_edit/form/form_config.tsx
+++ b/x-pack/plugins/synthetics/public/apps/synthetics/components/monitor_add_edit/form/form_config.tsx
@@ -214,7 +214,7 @@ export const FORM_CONFIG = (readOnly: boolean): FieldConfig => ({
       FIELD(readOnly)[AlertConfigKey.STATUS_ENABLED],
     ],
     step3: [FIELD(readOnly)['source.inline'], FIELD(readOnly)[ConfigKey.PARAMS]],
-    scriptEdit: [FIELD(readOnly)['source.inline']],
+    scriptEdit: [FIELD(readOnly)['source.inline'], FIELD(readOnly)[ConfigKey.PARAMS]],
     advanced: [
       {
         ...DEFAULT_DATA_OPTIONS(readOnly),