From 50de9464b6f6901dfabee7fbef094a51d45af282 Mon Sep 17 00:00:00 2001
From: JoeEverest <42711226+JoeEverest@users.noreply.github.com>
Date: Sat, 21 Mar 2026 20:05:45 -0400
Subject: [PATCH] fix(web): apply sticky model selection when reusing existing
 draft threads

Only brand-new threads had the sticky model/provider applied. When an
existing draft thread was found for the project (the common case), the
model and provider were left as null, causing a fallback to GPT 5.4.

When reusing a draft that already has a user-set model, preserve the
user's explicit choice instead of overwriting it with the sticky model.

Closes #1276

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
---
 apps/web/src/hooks/useHandleNewThread.ts | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/apps/web/src/hooks/useHandleNewThread.ts b/apps/web/src/hooks/useHandleNewThread.ts
index e31809cdd..ee7bc13b0 100644
--- a/apps/web/src/hooks/useHandleNewThread.ts
+++ b/apps/web/src/hooks/useHandleNewThread.ts
@@ -50,6 +50,16 @@ export function useHandleNewThread() {
       const hasBranchOption = options?.branch !== undefined;
       const hasWorktreePathOption = options?.worktreePath !== undefined;
       const hasEnvModeOption = options?.envMode !== undefined;
+      const applyStickyModel = (threadId: ThreadId, draftModel?: string | null) => {
+        if (stickyModel && !draftModel) {
+          setProvider(threadId, inferProviderForModel(stickyModel));
+          setModel(threadId, stickyModel);
+        }
+        if (!draftModel && Object.keys(stickyModelOptions).length > 0) {
+          setModelOptions(threadId, stickyModelOptions);
+        }
+      };
+
       const storedDraftThread = getDraftThreadByProjectId(projectId);
       const latestActiveDraftThread: DraftThreadState | null = routeThreadId
         ? getDraftThread(routeThreadId)
@@ -64,6 +74,9 @@ export function useHandleNewThread() {
             });
           }
           setProjectDraftThreadId(projectId, storedDraftThread.threadId);
+          const existingDraft =
+            useComposerDraftStore.getState().draftsByThreadId[storedDraftThread.threadId];
+          applyStickyModel(storedDraftThread.threadId, existingDraft?.model);
           if (routeThreadId === storedDraftThread.threadId) {
             return;
           }
@@ -89,6 +102,8 @@ export function useHandleNewThread() {
           });
         }
         setProjectDraftThreadId(projectId, routeThreadId);
+        const existingDraft = useComposerDraftStore.getState().draftsByThreadId[routeThreadId];
+        applyStickyModel(routeThreadId, existingDraft?.model);
         return Promise.resolve();
       }
 
@@ -102,13 +117,7 @@ export function useHandleNewThread() {
           envMode: options?.envMode ?? "local",
           runtimeMode: DEFAULT_RUNTIME_MODE,
         });
-        if (stickyModel) {
-          setProvider(threadId, inferProviderForModel(stickyModel));
-          setModel(threadId, stickyModel);
-        }
-        if (Object.keys(stickyModelOptions).length > 0) {
-          setModelOptions(threadId, stickyModelOptions);
-        }
+        applyStickyModel(threadId);
 
         await navigate({
           to: "/$threadId",