diff --git a/rfc/0057-sdk3-analytics.md b/rfc/0057-sdk3-analytics.md
index 356fb9e..b55e76b 100644
--- a/rfc/0057-sdk3-analytics.md
+++ b/rfc/0057-sdk3-analytics.md
@@ -191,6 +191,25 @@ class AnalyticsWarning {
 }
 ```
 
+## Cluster compatibility
+With the upcoming release of Enterprise Analytics, and the risk of users accidentally using operational SDKs against it, a compatibility check is being added.
+
+[MB-67103](https://jira.issues.couchbase.com/browse/MB-67103) adds to the cluster and bucket configs a `prodName` string field identifying the cluster type.
+
+Before performing each analytics operation, check the cluster config, and iff the prodName field is present, check if it starts with "Couchbase Server".  If it doesn't, fast-fail the request with a generic `CouchbaseException`.  A suitable error message could be:
+
+```
+var errStr = "This '${prodName}' cluster cannot be used with this SDK, which is intended for use with operational clusters."
+if (prodName == "Enterprise Analytics") {
+  errStr += ". For this cluster, an Enterprise Analytics SDK should be used."
+}
+throw new CouchbaseException(errStr)
+```
+
+If the cluster config is not yet available, wait for it using the request timeout.  On timeout follow standard timeout rules.
+
+For discussion of why "Couchbase Server" is matched, and why we check it starts with rather than the exact string, see the MB.
+
 # Changelog
 
 * Sept 27, 2019 - Revision #1 (by Michael Nitschinger)
@@ -201,6 +220,8 @@ class AnalyticsWarning {
   * Correct `AnalyticsStatus` enum values.
 * April 30, 2025 - Revision #3 (by Dimitris Christodoulou)
   * Allow setting both positional and named parameters.
+* June 19, 2025 - Revision #4 (by Graham Pople)
+  * Add check for operational cluster.
 
 # Signoff