Custom Chat Completion Suggestions API

paper-api/src/main/java/org/bukkit/entity/Player.java

@@ -3445,6 +3445,31 @@ public interface Player extends HumanEntity, Conversable, OfflinePlayer, PluginM
     void sendOpLevel(byte level);
     // Paper end - sendOpLevel API
 
+    // Paper start - custom chat completions API
+    /**
+     * Adds custom chat completion suggestions that the client will
+     * suggest when typing in chat.
+     *
+     * @param completions custom completions
+     * @deprecated use {@link #addCustomChatCompletions(Collection)}
+     */
+    @Deprecated(since = "1.20.1")
+    void addAdditionalChatCompletions(@NotNull java.util.Collection<String> completions);
+
+    /**
+     * Removes custom chat completion suggestions that the client
+     * suggests when typing in chat.
+     *
+     * Note: this only applies to previously added custom completions,
+     * online player names are always suggested and cannot be removed.
+     *
+     * @param completions custom completions
+     * @deprecated use {@link #addCustomChatCompletions(Collection)}
+     */
+    @Deprecated(since = "1.20.1")
+    void removeAdditionalChatCompletions(@NotNull java.util.Collection<String> completions);
+    // Paper end - custom chat completions API
+
     // Spigot start
     public class Spigot extends Entity.Spigot {