--- a/net/minecraft/network/chat/ChatDecorator.java
+++ b/net/minecraft/network/chat/ChatDecorator.java
@@ -5,7 +_,14 @@
 
 @FunctionalInterface
 public interface ChatDecorator {
-    ChatDecorator PLAIN = (player, message) -> message;
-
-    Component decorate(@Nullable ServerPlayer player, Component message);
+    ChatDecorator PLAIN = (player, message) -> java.util.concurrent.CompletableFuture.completedFuture(message); // Paper - adventure; support async chat decoration events
+
+    @io.papermc.paper.annotation.DoNotUse @Deprecated // Paper - adventure; support chat decoration events (callers should use the overload with CommandSourceStack)
+    java.util.concurrent.CompletableFuture<Component> decorate(@Nullable ServerPlayer player, Component message); // Paper - adventure; support async chat decoration events
+
+    // Paper start - adventure; support async chat decoration events
+    default java.util.concurrent.CompletableFuture<Component> decorate(@Nullable ServerPlayer sender, @Nullable net.minecraft.commands.CommandSourceStack commandSourceStack, Component message) {
+        throw new UnsupportedOperationException("Must override this implementation");
+    }
+    // Paper end - adventure; support async chat decoration events
 }
