Allow dot-prefix agentless

Author: orestisfl

modules/dot-prefix-validation/src/main/java/org/elasticsearch/validation/DotPrefixValidator.java

@@ -57,6 +57,7 @@ public abstract class DotPrefixValidator<RequestType> implements MappedActionFil
      * to use an internal origin for the client. These are shorter-term
      * workarounds until that work can be completed.
      *
+     * .agentless-* is used by stateful agentless integrations
      * .elastic-connectors-* is used by enterprise search
      * .ml-* is used by ML
      * .slo-observability-* is used by Observability
@@ -70,6 +71,7 @@ public abstract class DotPrefixValidator<RequestType> implements MappedActionFil
     public static Setting<List<String>> IGNORED_INDEX_PATTERNS_SETTING = Setting.stringListSetting(
         "cluster.indices.validate_ignored_dot_patterns",
         List.of(
+            "\\.agentless-.+",
             "\\.ml-state-\\d+",
             "\\.slo-observability\\.sli-v\\d+.*",
             "\\.slo-observability\\.summary-v\\d+.*",

modules/dot-prefix-validation/src/test/java/org/elasticsearch/validation/DotPrefixValidatorTests.java

@@ -67,6 +67,7 @@ public void testValidation() {
 
         // Test ignored patterns
         nonOpV.validateIndices(Set.of(".ml-state-21309"));
+        nonOpV.validateIndices(Set.of(".agentless-state-httpjson-okta.system-384301a9-f0e7-4f76-9656-f5a9330932e7"));
         nonOpV.validateIndices(Set.of(">.ml-state-21309>"));
         nonOpV.validateIndices(Set.of(".slo-observability.sli-v2"));
         nonOpV.validateIndices(Set.of(".slo-observability.sli-v2.3"));