Fix plan follow-up mode switching and submission text

juliusmarminge · juliusmarminge · commit 3a5b3b6b763f · 2026-03-05T23:00:32.000-08:00
- Extract follow-up submission resolution into `resolvePlanFollowUpSubmission`
- Send implementation prompt in default mode when follow-up text is empty
- Keep composer mode toggle synced when starting same-thread implementation turns
- Add tests for follow-up submission behavior
diff --git a/apps/web/src/components/ChatView.tsx b/apps/web/src/components/ChatView.tsx
@@ -92,6 +92,7 @@ import {
   buildPlanImplementationPrompt,
   buildProposedPlanMarkdownFilename,
   proposedPlanTitle,
+  resolvePlanFollowUpSubmission,
 } from "../proposedPlan";
 import { truncateTitle } from "../truncateTitle";
 import {
@@ -2318,19 +2319,18 @@ export default function ChatView({ threadId }: ChatViewProps) {
     }
     const trimmed = prompt.trim();
     if (showPlanFollowUpPrompt && activeProposedPlan) {
-      const followUpText =
-        trimmed.length > 0
-          ? trimmed
-          : buildPlanImplementationPrompt(activeProposedPlan.planMarkdown);
-      const nextInteractionMode = trimmed.length > 0 ? "plan" : "default";
+      const followUp = resolvePlanFollowUpSubmission({
+        draftText: trimmed,
+        planMarkdown: activeProposedPlan.planMarkdown,
+      });
       promptRef.current = "";
       clearComposerDraftContent(activeThread.id);
       setComposerHighlightedItemId(null);
       setComposerCursor(0);
       setComposerTrigger(null);
       await onSubmitPlanFollowUp({
-        text: followUpText,
-        interactionMode: nextInteractionMode,
+        text: followUp.text,
+        interactionMode: followUp.interactionMode,
       });
       return;
     }
@@ -2795,6 +2795,10 @@ export default function ChatView({ threadId }: ChatViewProps) {
           interactionMode: nextInteractionMode,
         });
 
+        // Keep the mode toggle and plan-follow-up banner in sync immediately
+        // while the same-thread implementation turn is starting.
+        setComposerDraftInteractionMode(threadIdForSend, nextInteractionMode);
+
         await api.orchestration.dispatchCommand({
           type: "thread.turn.start",
           commandId: newCommandId(),
@@ -2840,6 +2844,7 @@ export default function ChatView({ threadId }: ChatViewProps) {
       selectedModel,
       selectedModelOptionsForDispatch,
       selectedProvider,
+      setComposerDraftInteractionMode,
       setThreadError,
       settings.enableAssistantStreaming,
     ],
diff --git a/apps/web/src/proposedPlan.test.ts b/apps/web/src/proposedPlan.test.ts
@@ -5,6 +5,7 @@ import {
   buildPlanImplementationPrompt,
   buildProposedPlanMarkdownFilename,
   proposedPlanTitle,
+  resolvePlanFollowUpSubmission,
 } from "./proposedPlan";
 
 describe("proposedPlanTitle", () => {
@@ -25,6 +26,32 @@ describe("buildPlanImplementationPrompt", () => {
   });
 });
 
+describe("resolvePlanFollowUpSubmission", () => {
+  it("switches to default mode when implementing the ready plan without extra text", () => {
+    expect(
+      resolvePlanFollowUpSubmission({
+        draftText: "   ",
+        planMarkdown: "## Ship it\n\n- step 1\n",
+      }),
+    ).toEqual({
+      text: "PLEASE IMPLEMENT THIS PLAN:\n## Ship it\n\n- step 1",
+      interactionMode: "default",
+    });
+  });
+
+  it("stays in plan mode when the user adds a follow-up prompt", () => {
+    expect(
+      resolvePlanFollowUpSubmission({
+        draftText: "Refine step 2 first",
+        planMarkdown: "## Ship it\n\n- step 1\n",
+      }),
+    ).toEqual({
+      text: "Refine step 2 first",
+      interactionMode: "plan",
+    });
+  });
+});
+
 describe("buildPlanImplementationThreadTitle", () => {
   it("uses the plan heading when building the implementation thread title", () => {
     expect(buildPlanImplementationThreadTitle("# Integrate RPC\n\nBody")).toBe(
diff --git a/apps/web/src/proposedPlan.ts b/apps/web/src/proposedPlan.ts
@@ -16,6 +16,27 @@ export function buildPlanImplementationPrompt(planMarkdown: string): string {
   return `PLEASE IMPLEMENT THIS PLAN:\n${planMarkdown.trim()}`;
 }
 
+export function resolvePlanFollowUpSubmission(input: {
+  draftText: string;
+  planMarkdown: string;
+}): {
+  text: string;
+  interactionMode: "default" | "plan";
+} {
+  const trimmedDraftText = input.draftText.trim();
+  if (trimmedDraftText.length > 0) {
+    return {
+      text: trimmedDraftText,
+      interactionMode: "plan",
+    };
+  }
+
+  return {
+    text: buildPlanImplementationPrompt(input.planMarkdown),
+    interactionMode: "default",
+  };
+}
+
 export function buildPlanImplementationThreadTitle(planMarkdown: string): string {
   const title = proposedPlanTitle(planMarkdown);
   if (!title) {
