fix: reset websocket lineage after final answers

Eva (agent) · claude · commit db85f7f9c450 · 2026-05-08T16:28:24.000+07:00
diff --git a/src/agents/openai-ws-request.ts b/src/agents/openai-ws-request.ts
@@ -78,6 +78,30 @@ function inputItemsStartWith(input: InputItem[], baseline: InputItem[]): boolean
   return baseline.every((item, index) => stringifyStable(item) === stringifyStable(input[index]));
 }
 
+function responseInputEndedWithFinalAnswer(input: InputItem[]): boolean {
+  const lastConversationItem = input.findLast(
+    (item) =>
+      item.type === "message" ||
+      item.type === "function_call" ||
+      item.type === "function_call_output",
+  );
+  return (
+    lastConversationItem?.type === "message" &&
+    lastConversationItem.role === "assistant" &&
+    lastConversationItem.phase === "final_answer"
+  );
+}
+
+function suffixStartsNewUserTurn(input: InputItem[]): boolean {
+  const firstConversationItem = input.find(
+    (item) =>
+      item.type === "message" ||
+      item.type === "function_call" ||
+      item.type === "function_call_output",
+  );
+  return firstConversationItem?.type === "message" && firstConversationItem.role === "user";
+}
+
 export function planOpenAIWebSocketRequestPayload(params: {
   fullPayload: ResponseCreateEvent;
   previousRequestPayload?: ResponseCreateEvent;
@@ -97,14 +121,22 @@ export function planOpenAIWebSocketRequestPayload(params: {
   ) {
     const baseline = [...previousInputItems, ...previousResponseInputItems];
     if (inputItemsStartWith(fullInputItems, baseline)) {
-      return {
-        mode: "incremental",
-        payload: {
-          ...params.fullPayload,
-          previous_response_id: params.previousResponseId,
-          input: fullInputItems.slice(baseline.length),
-        },
-      };
+      const incrementalInput = fullInputItems.slice(baseline.length);
+      if (
+        !(
+          responseInputEndedWithFinalAnswer(previousResponseInputItems) &&
+          suffixStartsNewUserTurn(incrementalInput)
+        )
+      ) {
+        return {
+          mode: "incremental",
+          payload: {
+            ...params.fullPayload,
+            previous_response_id: params.previousResponseId,
+            input: incrementalInput,
+          },
+        };
+      }
     }
   }
 
diff --git a/src/agents/openai-ws-stream.test.ts b/src/agents/openai-ws-stream.test.ts
@@ -1835,6 +1835,39 @@ describe("planOpenAIWebSocketRequestPayload", () => {
     expect(plan.payload.input).toEqual([{ type: "message", role: "user", content: "Next" }]);
   });
 
+  it("uses full context when a new user turn follows a final answer", () => {
+    const previousInputItems: InputItem[] = [{ type: "message", role: "user", content: "Fix X" }];
+    const previousRequest: ResponseCreateEvent = {
+      type: "response.create",
+      model: "gpt-5.4",
+      store: false,
+      instructions: "You are helpful.",
+      input: previousInputItems,
+    };
+    const previousResponseInputItems: InputItem[] = [
+      { type: "message", role: "assistant", content: "Done — fixed X.", phase: "final_answer" },
+    ];
+    const fullPayload: ResponseCreateEvent = {
+      ...previousRequest,
+      input: [
+        ...previousInputItems,
+        ...previousResponseInputItems,
+        { type: "message", role: "user", content: "Now inspect Y" },
+      ],
+    };
+
+    const plan = planOpenAIWebSocketRequestPayload({
+      fullPayload,
+      previousRequestPayload: previousRequest,
+      previousResponseId: "resp_prev_final",
+      previousResponseInputItems,
+    });
+
+    expect(plan.mode).toBe("full_context");
+    expect(plan.payload.previous_response_id).toBeUndefined();
+    expect(plan.payload.input).toEqual(fullPayload.input);
+  });
+
   it("falls back to full context when non-input fields differ", () => {
     const previousInputItems: InputItem[] = [{ type: "message", role: "user", content: "Hello" }];
     const previousRequest: ResponseCreateEvent = {
