fix(web): reset send phase when latest turn settles

apps/web/src/components/ChatView.tsx

@@ -57,6 +57,7 @@ import {
   deriveWorkLogEntries,
   hasActionableProposedPlan,
   hasToolActivityForTurn,
+  hasSettledLatestTurnAdvanced,
   isLatestTurnSettled,
   formatElapsed,
 } from "../session-logic";
@@ -388,6 +389,7 @@ export default function ChatView({ threadId }: ChatViewProps) {
   const attachmentPreviewHandoffByMessageIdRef = useRef<Record<string, string[]>>({});
   const attachmentPreviewHandoffTimeoutByMessageIdRef = useRef<Record<string, number>>({});
   const sendInFlightRef = useRef(false);
+  const sendBaselineTurnIdRef = useRef<TurnId | null>(null);
   const dragDepthRef = useRef(0);
   const terminalOpenByThreadRef = useRef<Record<string, boolean>>({});
   const setMessagesScrollContainerRef = useCallback((element: HTMLDivElement | null) => {
@@ -2061,12 +2063,17 @@ export default function ChatView({ threadId }: ChatViewProps) {
     };
   }, [phase]);
 
-  const beginSendPhase = useCallback((nextPhase: Exclude<SendPhase, "idle">) => {
-    setSendStartedAt((current) => current ?? new Date().toISOString());
-    setSendPhase(nextPhase);
-  }, []);
+  const beginSendPhase = useCallback(
+    (nextPhase: Exclude<SendPhase, "idle">) => {
+      sendBaselineTurnIdRef.current = activeLatestTurn?.turnId ?? null;
+      setSendStartedAt((current) => current ?? new Date().toISOString());
+      setSendPhase(nextPhase);
+    },
+    [activeLatestTurn?.turnId],
+  );
 
   const resetSendPhase = useCallback(() => {
+    sendBaselineTurnIdRef.current = null;
     setSendPhase("idle");
     setSendStartedAt(null);
   }, []);
@@ -2092,6 +2099,23 @@ export default function ChatView({ threadId }: ChatViewProps) {
     sendPhase,
   ]);
 
+  useEffect(() => {
+    if (sendPhase === "idle") {
+      return;
+    }
+    if (
+      !hasSettledLatestTurnAdvanced(
+        activeLatestTurn,
+        activeThread?.session ?? null,
+        sendBaselineTurnIdRef.current,
+      )
+    ) {
+      return;
+    }
+
+    resetSendPhase();
+  }, [activeLatestTurn, activeThread?.session, resetSendPhase, sendPhase]);
+
   useEffect(() => {
     if (!activeThreadId) return;
     const previous = terminalOpenByThreadRef.current[activeThreadId] ?? false;

apps/web/src/session-logic.ts

@@ -139,6 +139,17 @@ export function isLatestTurnSettled(
   return true;
 }
 
+export function hasSettledLatestTurnAdvanced(
+  latestTurn: LatestTurnTiming | null,
+  session: SessionActivityState | null,
+  baselineTurnId: TurnId | null,
+): boolean {
+  if (!isLatestTurnSettled(latestTurn, session)) {
+    return false;
+  }
+  return (latestTurn?.turnId ?? null) !== baselineTurnId;
+}
+
 export function deriveActiveWorkStartedAt(
   latestTurn: LatestTurnTiming | null,
   session: SessionActivityState | null,