fix: show first chat message immediately in new sessions

yottahmd · yottahmd · commit 29dcf58b3515 · 2026-03-16T15:07:14.000+09:00
The first message in a new agent chat session was not displayed
optimistically. Two issues caused this:

1. ChatMessages early-returned with the empty-state placeholder when
   messages was empty, ignoring pendingUserMessage entirely.

2. applySessionSnapshot and applySessionEvent cleared pendingUserMessage
   when the server reported working=true, even before the actual user
   message appeared in the stream. For a brand-new session this created
   a window where both pending and real messages were absent.

Now the empty-state check accounts for pendingUserMessage, and the
pending bubble is only cleared once the real user message arrives.
diff --git a/ui/src/features/agent/components/ChatMessages.tsx b/ui/src/features/agent/components/ChatMessages.tsx
@@ -49,7 +49,7 @@ export function ChatMessages({
     return ids;
   }, [messages]);
 
-  if (messages.length === 0) {
+  if (messages.length === 0 && !pendingUserMessage) {
     return (
       <div className="flex-1 flex items-center justify-center text-muted-foreground p-4 bg-popover">
         <div className="text-center">
diff --git a/ui/src/features/agent/hooks/useAgentChat.ts b/ui/src/features/agent/hooks/useAgentChat.ts
@@ -252,11 +252,10 @@ export function useAgentChat() {
     const nextMessages = snapshot.messages || [];
     if (
       pendingUserMessage &&
-      (nextMessages.some(
+      nextMessages.some(
         (message) =>
           message.type === 'user' && message.content === pendingUserMessage
-      ) ||
-        snapshot.session_state?.working)
+      )
     ) {
       setPendingUserMessage(null);
     }
@@ -292,11 +291,9 @@ export function useAgentChat() {
       setMessages((current) => mergeMessages(current, event.messages || []));
     }
 
-    // Clear the pending message when the server acknowledges it is working,
-    // even if the user message hasn't appeared in the stream yet.
-    if (pendingUserMessage && event.session_state?.working) {
-      setPendingUserMessage(null);
-    }
+    // Only clear the pending message once the actual user message appears in
+    // the stream. Previously this also cleared on working=true, but that
+    // caused the pending bubble to vanish before the real message arrived.
 
     if (event.session_state) {
       setSessionState(event.session_state);
