diff --git a/apps/web/src/composerDraftStore.test.ts b/apps/web/src/composerDraftStore.test.ts
index e1d9d462a661..068bb1ff41f0 100644
--- a/apps/web/src/composerDraftStore.test.ts
+++ b/apps/web/src/composerDraftStore.test.ts
@@ -1458,17 +1458,18 @@ describe("composerDraftStore project draft thread mapping", () => {
     expect(draftFor(threadId, TEST_ENVIRONMENT_ID)?.prompt).toBe("keep me");
   });
 
-  it("finalizes a promoted draft after the canonical thread route is active", () => {
+  it("moves composer edits made during promotion to the canonical thread", () => {
     const store = useComposerDraftStore.getState();
     store.setProjectDraftThreadId(projectRef, draftId, { threadId });
-    store.setPrompt(draftId, "promote me");
     markPromotedDraftThread(threadId);
+    store.setPrompt(draftId, "typed during setup");
 
     finalizePromotedDraftThreadByRef(scopeThreadRef(TEST_ENVIRONMENT_ID, threadId));
 
     expect(useComposerDraftStore.getState().getDraftThreadByProjectRef(projectRef)).toBeNull();
     expect(useComposerDraftStore.getState().getDraftThread(draftId)).toBeNull();
     expect(draftByKey(draftId)).toBeUndefined();
+    expect(draftFor(threadId, TEST_ENVIRONMENT_ID)?.prompt).toBe("typed during setup");
   });
 
   it("finalizes a matching materialized draft even when promotion was not pre-marked", () => {
@@ -1481,6 +1482,7 @@ describe("composerDraftStore project draft thread mapping", () => {
     expect(useComposerDraftStore.getState().getDraftThreadByProjectRef(projectRef)).toBeNull();
     expect(useComposerDraftStore.getState().getDraftThread(draftId)).toBeNull();
     expect(draftByKey(draftId)).toBeUndefined();
+    expect(draftFor(threadId, TEST_ENVIRONMENT_ID)?.prompt).toBe("promote me");
   });
 
   it("updates branch context on an existing draft thread", () => {
diff --git a/apps/web/src/composerDraftStore.ts b/apps/web/src/composerDraftStore.ts
index 6ef8c6518858..0032ababbae4 100644
--- a/apps/web/src/composerDraftStore.ts
+++ b/apps/web/src/composerDraftStore.ts
@@ -1583,6 +1583,7 @@ function removeDraftThreadReferences(
     | "logicalProjectDraftThreadKeyByLogicalProjectKey"
   >,
   threadKey: string,
+  composerDestination?: ScopedThreadRef,
 ): Pick<
   ComposerDraftStoreState,
   | "draftThreadsByThreadKey"
@@ -1597,7 +1598,11 @@ function removeDraftThreadReferences(
   const { [threadKey]: _removedDraftThread, ...restDraftThreadsByThreadKey } =
     state.draftThreadsByThreadKey;
   const { [threadKey]: removedComposerDraft, ...restDraftsByThreadKey } = state.draftsByThreadKey;
-  revokeDraftThreadPreviewUrls(removedComposerDraft);
+  if (composerDestination && removedComposerDraft) {
+    restDraftsByThreadKey[composerTargetKey(composerDestination)] = removedComposerDraft;
+  } else {
+    revokeDraftThreadPreviewUrls(removedComposerDraft);
+  }
   return {
     draftsByThreadKey: restDraftsByThreadKey,
     draftThreadsByThreadKey: restDraftThreadsByThreadKey,
@@ -2785,10 +2790,10 @@ const composerDraftStore = create<ComposerDraftStoreState>()(
           }
           set((state) => {
             const existing = state.draftThreadsByThreadKey[threadKey];
-            if (!isDraftThreadPromoting(existing)) {
+            if (!existing || !isDraftThreadPromoting(existing)) {
               return state;
             }
-            return removeDraftThreadReferences(state, threadKey);
+            return removeDraftThreadReferences(state, threadKey, existing.promotedTo ?? undefined);
           });
         },
         clearDraftThread: (threadRef) => {