diff --git a/web/src/stores/message.ts b/web/src/stores/message.ts
index 5d5a68c..6d0d8f5 100644
--- a/web/src/stores/message.ts
+++ b/web/src/stores/message.ts
@@ -92,19 +92,12 @@ export const useMessageStore = create<MessageState>((set) => ({
   sendMessage: async (channelId, content, replyTo) => {
     const body: { content: string; reply_to?: string } = { content };
     if (replyTo) body.reply_to = replyTo;
+    // ponytail: don't append here — WS MESSAGE_CREATE broadcast is the single source of truth.
+    // Appending in both places caused double messages when the WS event arrived before the HTTP response.
     const message = await api.post<Message>(
       `/channels/${channelId}/messages`,
       body,
     );
-    set((state) => {
-      const list = state.messagesByChannel[channelId] || [];
-      return {
-        messagesByChannel: {
-          ...state.messagesByChannel,
-          [channelId]: [...list, message],
-        },
-      };
-    });
     return message;
   },