fix: infer provider from thread model when no session or explicit selection exists

cursoragent · cursoragent · commit 62e136dcc832 · 2026-02-27T20:12:36.000Z
When a thread has a Claude model slug but no active session and no entry
in selectedProviderByThread (e.g., after a page refresh), selectedProvider
incorrectly fell back to 'codex'. This caused resolveModelSlugForProvider
to resolve the Claude slug against the codex model catalog, showing the
wrong model/provider and sending turns to the wrong provider.

Use the existing inferProviderForThreadModel helper (now exported from
store.ts) to infer the correct provider from the thread's model slug
before falling back to the 'codex' default.
diff --git a/apps/web/src/components/ChatView.tsx b/apps/web/src/components/ChatView.tsx
@@ -51,7 +51,7 @@ import {
   formatTimestamp,
 } from "../session-logic";
 import { isScrollContainerNearBottom } from "../chat-scroll";
-import { useStore } from "../store";
+import { inferProviderForThreadModel, useStore } from "../store";
 import { truncateTitle } from "../truncateTitle";
 import {
   DEFAULT_THREAD_TERMINAL_ID,
@@ -413,7 +413,12 @@ export default function ChatView({ threadId }: ChatViewProps) {
   const selectedProvider: ProviderKind =
     (activeThread?.id ? selectedProviderByThread[activeThread.id] : undefined) ??
     sessionProvider ??
-    "codex";
+    (activeThread?.model
+      ? inferProviderForThreadModel({
+          model: activeThread.model,
+          sessionProviderName: activeThread.session?.provider ?? null,
+        })
+      : "codex");
   const selectedModel = resolveModelSlugForProvider(
     selectedProvider,
     activeThread?.model ?? activeProject?.model ?? getDefaultModel(selectedProvider) ?? DEFAULT_MODEL,
diff --git a/apps/web/src/store.ts b/apps/web/src/store.ts
@@ -198,7 +198,7 @@ function toLegacyProvider(providerName: string | null): "codex" | "claudeCode" {
 const CODEX_MODEL_SLUGS = new Set(getModelOptions("codex").map((option) => option.slug));
 const CLAUDE_MODEL_SLUGS = new Set(getModelOptions("claudeCode").map((option) => option.slug));
 
-function inferProviderForThreadModel(input: {
+export function inferProviderForThreadModel(input: {
   readonly model: string;
   readonly sessionProviderName: string | null;
 }): "codex" | "claudeCode" {
