diff --git a/frontend/src/app/pages/AgentChat/AgentChat.tsx b/frontend/src/app/pages/AgentChat/AgentChat.tsx
index a7a86596..45d5ded4 100644
--- a/frontend/src/app/pages/AgentChat/AgentChat.tsx
+++ b/frontend/src/app/pages/AgentChat/AgentChat.tsx
@@ -1628,7 +1628,8 @@ const AgentChat: React.FC<AgentChatProps> = ({ sessionId: sessionIdProp, onClose
           >
             {/* The welcome greeting is the FIRST thing and it's the agent talking, no user message above it, so give it real air under the header instead of sitting flush at the top. */}
             {/* Non-welcome chats still need headroom: at pt 0 the first user bubble's top edge clipped under the header. */}
-            <Box sx={{ pt: session.is_welcome_draft ? 4 : 2 }}>
+            {/* Fullscreen carries the window title bar OVER the transcript, so the first message (and any attachment chips above it) needs to start below that chrome, not under it. */}
+            <Box sx={{ pt: fullscreenChat ? 7 : session.is_welcome_draft ? 4 : 2 }}>
             {session.context_overflow && (() => {
               const reason = session.context_overflow.reason;
               const isAuth = reason === 'openswarm_pro_auth_expired' || reason === 'anthropic_auth_invalid' || reason === 'auth_error';