diff --git a/Client-Side Components/Catalog Client Script/Validate CI selection via GlideAjax with submit guard/CIValidationAjax.js b/Client-Side Components/Catalog Client Script/Validate CI selection via GlideAjax with submit guard/CIValidationAjax.js
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+++ b/Client-Side Components/Catalog Client Script/Validate CI selection via GlideAjax with submit guard/CIValidationAjax.js	
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+var CIValidationAjax = Class.create();
+CIValidationAjax.prototype = Object.extendsObject(AbstractAjaxProcessor, {
+  validateCi: function() {
+    var ciSysId = this.getParameter('sysparm_ci');
+    var result = { valid: false, display: '', message: '' };
+
+    if (!ciSysId) {
+      result.message = 'No CI provided.';
+      return JSON.stringify(result);
+    }
+
+    var ci = new GlideRecord('cmdb_ci');
+    if (!ci.get(ciSysId)) {
+      result.message = 'CI not found.';
+      return JSON.stringify(result);
+    }
+
+    result.display = ci.getDisplayValue();
+
+    // Example rules: CI must be operational and have an assignment group
+    var isOperational = String(ci.install_status) === '1'; // installed
+    var hasGroup = !!ci.assignment_group;
+
+    if (isOperational && hasGroup) {
+      result.valid = true;
+      return JSON.stringify(result);
+    }
+
+    var reasons = [];
+    if (!isOperational) reasons.push('CI is not operational');
+    if (!hasGroup) reasons.push('no assignment group is set');
+    result.message = 'CI is not valid: ' + reasons.join('; ') + '.';
+    return JSON.stringify(result);
+  },
+
+  isPublic: function() { return true; }
+});
diff --git a/Client-Side Components/Catalog Client Script/Validate CI selection via GlideAjax with submit guard/README.md b/Client-Side Components/Catalog Client Script/Validate CI selection via GlideAjax with submit guard/README.md
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+++ b/Client-Side Components/Catalog Client Script/Validate CI selection via GlideAjax with submit guard/README.md	
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+# Validate CI selection via GlideAjax with submit guard
+
+## What this solves
+End users sometimes pick CIs that are retired or unsupported for fulfilment. This client script validates a selected CI using GlideAjax and prevents submission if the CI fails checks.
+This could also be used where some CIs are supported by third parties and prevent use in incorrect forms.
+
+## Where to use
+- Catalog Item with a reference variable to `cmdb_ci`
+- Add the client script as an onChange on that variable
+- Install the Script Include in the same scope
+
+## How it works
+- onChange reads the selected CI sys_id
+- Calls Script Include via GlideAjax
+- Server checks for active CI and support group presence
+- Client displays messages and disables submit if invalid
+
+## References
+- GlideAjax  
+  https://www.servicenow.com/docs/bundle/zurich-api-reference/page/app-store/dev_portal/API_reference/GlideAjax/concept/c_GlideAjaxAPI.html
+- GlideForm client API  
+  https://www.servicenow.com/docs/bundle/zurich-api-reference/page/app-store/dev_portal/API_reference/GlideForm/concept/c_GlideFormAPI.html
+- GlideRecord  
+  https://www.servicenow.com/docs/bundle/zurich-api-reference/page/app-store/dev_portal/API_reference/GlideRecord/concept/c_GlideRecordAPI.html
diff --git a/Client-Side Components/Catalog Client Script/Validate CI selection via GlideAjax with submit guard/catalog_ci_validate_onchange.js b/Client-Side Components/Catalog Client Script/Validate CI selection via GlideAjax with submit guard/catalog_ci_validate_onchange.js
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+++ b/Client-Side Components/Catalog Client Script/Validate CI selection via GlideAjax with submit guard/catalog_ci_validate_onchange.js	
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+function onChange(control, oldValue, newValue, isLoading) {
+  if (isLoading) return;
+
+  var VAR_NAME = 'ci'; // replace with your CI variable name
+
+  // Clear old messages and re-enable submit by default
+  g_form.clearMessages();
+  if (g_form.setSubmitEnabled) g_form.setSubmitEnabled(true);
+
+  var ciSysId = g_form.getValue(VAR_NAME);
+  if (!ciSysId) return;
+
+  var ga = new GlideAjax('CIValidationAjax');
+  ga.addParam('sysparm_name', 'validateCi');
+  ga.addParam('sysparm_ci', ciSysId);
+
+  ga.getXMLAnswer(function(answer) {
+    try {
+      var res = JSON.parse(answer || '{}');
+      if (res.valid) {
+        g_form.addInfoMessage('CI is valid and supported: ' + (res.display || ciSysId));
+      } else {
+        g_form.addErrorMessage(res.message || 'Selected CI is not valid for this request.');
+        if (g_form.setSubmitEnabled) g_form.setSubmitEnabled(false);
+      }
+    } catch (e) {
+      g_form.addErrorMessage('Validation failed. Please try again or choose another CI.');
+      if (g_form.setSubmitEnabled) g_form.setSubmitEnabled(false);
+    }
+  });
+}