fix: prevent steering during final response streaming

Author: NoOne7135

custom/SteerQueue.vue

@@ -28,8 +28,11 @@
         </span>
         <button
           type="button"
-          class="shrink-0 rounded-md px-2 py-1 text-xs font-medium text-lightPrimary transition-colors hover:bg-lightPrimary/10 dark:text-darkPrimary dark:hover:bg-darkPrimary/10"
-          :title="$t('Steer into the current response')"
+          class="shrink-0 rounded-md px-2 py-1 text-xs font-medium text-lightPrimary transition-colors hover:bg-lightPrimary/10 disabled:cursor-not-allowed disabled:opacity-40 disabled:hover:bg-transparent dark:text-darkPrimary dark:hover:bg-darkPrimary/10 dark:disabled:hover:bg-transparent"
+          :disabled="agentStore.isFinalResponseStreaming"
+          :title="agentStore.isFinalResponseStreaming
+            ? $t('The final response is streaming; this message will be sent after it finishes')
+            : $t('Steer into the current response')"
           @click="agentStore.steerQueuedMessage(item.id)"
         >
           {{ $t('Steer') }}

custom/composables/agentStore/useAgentSteerQueue.ts

@@ -13,12 +13,14 @@ export type QueuedMessage = {
 type CreateAgentSteerQueueOptions = {
   activeSessionId: Ref<string | null>;
   currentChat: ShallowRef<Chat<any> | null | undefined>;
+  isFinalResponseStreaming: Ref<boolean>;
   sendMessage: (text: string) => void | Promise<void>;
 };
 
 export function createAgentSteerQueue({
   activeSessionId,
   currentChat,
+  isFinalResponseStreaming,
   sendMessage,
 }: CreateAgentSteerQueueOptions) {
   const queue = ref<QueuedMessage[]>([]);
@@ -146,7 +148,10 @@ export function createAgentSteerQueue({
   async function steerQueuedMessage(id: string) {
     const item = queue.value.find((candidate: QueuedMessage) => candidate.id === id);
     const sessionId = activeSessionId.value;
-    if (!item || !sessionId || sessionId === PRE_SESSION_ID) {
+    // A steer is only consumed before a subsequent model call. Once the assistant is
+    // streaming its final text there is no such call left, so retain this item for the
+    // normal FIFO follow-up instead of silently losing the instruction server-side.
+    if (!item || !sessionId || sessionId === PRE_SESSION_ID || isFinalResponseStreaming.value) {
       return;
     }
     removeQueuedMessage(id);

custom/composables/useAgentStore.ts

@@ -238,9 +238,22 @@ export const useAgentStore = defineStore('agent', () => {
     return status === 'submitted' || status === 'streaming' || hasPendingToolApproval.value;
   });
 
+  // During an assistant text stream, a newly submitted steer cannot be consumed: the
+  // steer middleware only runs before another model call. Keep it in the queue so it
+  // becomes a normal follow-up when the current turn ends.
+  const isFinalResponseStreaming = computed(() => {
+    const chat = currentChat.value as any;
+    const lastMessage = chat?.lastMessage;
+
+    return chat?.status === 'streaming'
+      && lastMessage?.role === 'assistant'
+      && lastMessage.parts?.some((part: any) => part.type === 'text' && part.state === 'streaming');
+  });
+
   const steerBuffer = createAgentSteerQueue({
     activeSessionId,
     currentChat,
+    isFinalResponseStreaming,
     sendMessage,
   });
 
@@ -646,6 +659,7 @@ export const useAgentStore = defineStore('agent', () => {
     //_________-Steer queue-_____________
     submitUserMessage,
     isTurnActive,
+    isFinalResponseStreaming,
     steerQueue: steerBuffer.queue,
     steerQueuedMessage: steerBuffer.steerQueuedMessage,
     removeQueuedMessage: steerBuffer.removeQueuedMessage,