diff --git a/cloud-core/src/main/java/org/incendo/cloud/caption/StandardCaptionKeys.java b/cloud-core/src/main/java/org/incendo/cloud/caption/StandardCaptionKeys.java
index 6ae7021bd..a6d3f3df1 100644
--- a/cloud-core/src/main/java/org/incendo/cloud/caption/StandardCaptionKeys.java
+++ b/cloud-core/src/main/java/org/incendo/cloud/caption/StandardCaptionKeys.java
@@ -50,7 +50,7 @@ public final class StandardCaptionKeys {
      */
     public static final Caption ARGUMENT_PARSE_FAILURE_CHAR = of("argument.parse.failure.char");
     /**
-     * Variables: {@code <input>}, {@code <stringMode>}
+     * Variables: {@code <input>}, {@code <string_mode>}
      */
     public static final Caption ARGUMENT_PARSE_FAILURE_STRING = of("argument.parse.failure.string");
     /**
@@ -58,7 +58,7 @@ public final class StandardCaptionKeys {
      */
     public static final Caption ARGUMENT_PARSE_FAILURE_UUID = of("argument.parse.failure.uuid");
     /**
-     * Variables: {@code <input>}, {@code <acceptableValues>}
+     * Variables: {@code <input>}, {@code <acceptable_values>}
      */
     public static final Caption ARGUMENT_PARSE_FAILURE_ENUM = of("argument.parse.failure.enum");
     /**
diff --git a/cloud-core/src/main/java/org/incendo/cloud/parser/standard/EnumParser.java b/cloud-core/src/main/java/org/incendo/cloud/parser/standard/EnumParser.java
index 31387ec0b..9685cd9e9 100644
--- a/cloud-core/src/main/java/org/incendo/cloud/parser/standard/EnumParser.java
+++ b/cloud-core/src/main/java/org/incendo/cloud/parser/standard/EnumParser.java
@@ -151,7 +151,7 @@ public EnumParseException(
                     context,
                     StandardCaptionKeys.ARGUMENT_PARSE_FAILURE_ENUM,
                     CaptionVariable.of("input", input),
-                    CaptionVariable.of("acceptableValues", join(enumClass))
+                    CaptionVariable.of("acceptable_values", join(enumClass)) // Adventure 5.x made MiniMessage tags stricter
             );
             this.input = input;
             this.enumClass = enumClass;
diff --git a/cloud-core/src/main/java/org/incendo/cloud/parser/standard/StringParser.java b/cloud-core/src/main/java/org/incendo/cloud/parser/standard/StringParser.java
index 38ee5f618..5e1608117 100644
--- a/cloud-core/src/main/java/org/incendo/cloud/parser/standard/StringParser.java
+++ b/cloud-core/src/main/java/org/incendo/cloud/parser/standard/StringParser.java
@@ -283,7 +283,7 @@ public StringParseException(
                     context,
                     StandardCaptionKeys.ARGUMENT_PARSE_FAILURE_STRING,
                     CaptionVariable.of("input", input),
-                    CaptionVariable.of("stringMode", stringMode.name())
+                    CaptionVariable.of("string_mode", stringMode.name()) // Adventure 5.x made MiniMessage tags stricter
             );
             this.input = input;
             this.stringMode = stringMode;