fix: resolve session provider on backend reads

Session history and token usage reads already have a stable app session id.
Passing provider and project hints from the frontend kept those reads coupled
with provider-specific state that the backend can resolve from the session row.

Resolve token usage provider server-side and narrow the session store read API
to session id plus pagination. This keeps provider-specific storage decisions
behind the backend boundary and makes reconnect, pagination, and load-all use
the same session-owned contract.

server/index.js

@@ -1135,7 +1135,6 @@ app.post('/api/projects/:projectId/upload-images', authenticateToken, async (req
 app.get('/api/projects/:projectId/sessions/:sessionId/token-usage', authenticateToken, async (req, res) => {
     try {
         const { projectId, sessionId } = req.params;
-        const { provider = 'claude' } = req.query;
         const homeDir = os.homedir();
 
         // Allow only safe characters in sessionId
@@ -1146,8 +1145,14 @@ app.get('/api/projects/:projectId/sessions/:sessionId/token-usage', authenticate
 
         // Provider artifacts on disk (JSONL file names, OpenCode sqlite rows)
         // are keyed by the provider-native session id, while the caller sends
-        // the app-facing id. Resolve the mapping once for all branches below.
+        // the app-facing id. Resolve provider and id mapping from the indexed
+        // session row so the frontend does not choose provider-specific paths.
         const sessionRow = sessionsDb.getSessionById(safeSessionId);
+        if (!sessionRow) {
+            return res.status(404).json({ error: 'Session not found', sessionId: safeSessionId });
+        }
+
+        const provider = sessionRow.provider || 'claude';
         const providerNativeSessionId = sessionRow?.provider_session_id || safeSessionId;
 
         // Handle Cursor sessions - they use SQLite and don't have token usage info

src/components/chat/hooks/useChatSessionState.ts

@@ -5,7 +5,7 @@ import { authenticatedFetch } from '../../../utils/api';
 import type { MarkSessionIdle, SessionActivityMap } from '../../../hooks/useSessionProtection';
 import type { Project, ProjectSession, LLMProvider } from '../../../types/app';
 import type { SessionStore, NormalizedMessage } from '../../../stores/useSessionStore';
-import type { ChatMessage, Provider } from '../types/types';
+import type { ChatMessage } from '../types/types';
 import { createCachedDiffCalculator, type DiffCalculator } from '../utils/messageTransforms';
 
 import { normalizedToChatMessages } from './useChatMessages';
@@ -328,18 +328,12 @@ export function useChatSessionState({
       if (allMessagesLoadedRef.current) return false;
       if (!hasMoreMessages || !selectedSession || !selectedProject) return false;
 
-      const sessionProvider = selectedSession.__provider || 'claude';
-
       isLoadingMoreRef.current = true;
       const previousScrollHeight = container.scrollHeight;
       const previousScrollTop = container.scrollTop;
 
       try {
         const slot = await sessionStore.fetchMore(selectedSession.id, {
-          provider: sessionProvider as LLMProvider,
-          // DB-assigned projectId replaces the legacy folder-derived name.
-          projectId: selectedProject.projectId,
-          projectPath: selectedProject.fullPath || selectedProject.path || '',
           limit: MESSAGES_PER_PAGE,
         });
         if (!slot || slot.serverMessages.length === 0) return false;
@@ -458,8 +452,7 @@ export function useChatSessionState({
       return;
     }
 
-    const provider = (selectedSession.__provider || localStorage.getItem('selected-provider') as Provider) || 'claude';
+    const sessionKey = `${selectedSession.id}:${selectedProject.projectId}`;
-    const sessionKey = `${selectedSession.id}:${selectedProject.projectId}:${provider}`;
 
     // Skip if already loaded and fresh
     if (lastLoadedSessionKeyRef.current === sessionKey && sessionStore.has(selectedSession.id) && !sessionStore.isStale(selectedSession.id)) {
@@ -512,9 +505,6 @@ export function useChatSessionState({
     // Fetch from server → store updates → chatMessages re-derives automatically
     setIsLoadingSessionMessages(true);
     sessionStore.fetchFromServer(selectedSession.id, {
-      provider: (selectedSession.__provider || provider) as LLMProvider,
-      projectId: selectedProject.projectId,
-      projectPath: selectedProject.fullPath || selectedProject.path || '',
       limit: MESSAGES_PER_PAGE,
       offset: 0,
     }).then(slot => {
@@ -544,15 +534,9 @@ export function useChatSessionState({
 
     const reloadExternalMessages = async () => {
       try {
-        const provider = (localStorage.getItem('selected-provider') as Provider) || 'claude';
-
         // Skip store refresh during active streaming
         if (!isProcessing) {
-          await sessionStore.refreshFromServer(selectedSession.id, {
+          await sessionStore.refreshFromServer(selectedSession.id);
-            provider: (selectedSession.__provider || provider) as LLMProvider,
-            projectId: selectedProject.projectId,
-            projectPath: selectedProject.fullPath || selectedProject.path || '',
-          });
 
           if (Boolean(autoScrollToBottom) && isNearBottom()) {
             setTimeout(() => scrollToBottom(), 200);
@@ -598,13 +582,9 @@ export function useChatSessionState({
 
     const scrollToTarget = async () => {
       if (!allMessagesLoadedRef.current && selectedSession && selectedProject) {
-        const sessionProvider = selectedSession.__provider || 'claude';
           try {
             // Load all messages into the store for search navigation
             const slot = await sessionStore.fetchFromServer(selectedSession.id, {
-              provider: sessionProvider as LLMProvider,
-              projectId: selectedProject.projectId,
-              projectPath: selectedProject.fullPath || selectedProject.path || '',
               limit: null,
               offset: 0,
             });
@@ -678,13 +658,10 @@ export function useChatSessionState({
       setTokenBudget(null);
       return;
     }
-    const sessionProvider = selectedSession.__provider || 'claude';
-
     const fetchInitialTokenUsage = async () => {
       try {
-        // Token usage endpoint is now keyed by the DB projectId.
+        // The backend resolves the provider from the indexed session row.
-        const params = new URLSearchParams({ provider: sessionProvider });
+        const url = `/api/projects/${selectedProject.projectId}/sessions/${selectedSession.id}/token-usage`;
-        const url = `/api/projects/${selectedProject.projectId}/sessions/${selectedSession.id}/token-usage?${params.toString()}`;
         const response = await authenticatedFetch(url);
         if (response.ok) {
           setTokenBudget(await response.json());
@@ -696,7 +673,7 @@ export function useChatSessionState({
       }
     };
     fetchInitialTokenUsage();
-  }, [selectedProject, selectedSession?.id, selectedSession?.__provider]);
+  }, [selectedProject, selectedSession?.id]);
 
   const visibleMessages = useMemo(() => {
     if (chatMessages.length <= visibleMessageCount) return chatMessages;
@@ -756,8 +733,6 @@ export function useChatSessionState({
   const loadAllMessages = useCallback(async () => {
     if (!selectedSession || !selectedProject) return;
     if (isLoadingAllMessages) return;
-    const sessionProvider = selectedSession.__provider || 'claude';
-
     const requestSessionId = selectedSession.id;
     allMessagesLoadedRef.current = true;
     isLoadingMoreRef.current = true;
@@ -770,9 +745,6 @@ export function useChatSessionState({
 
     try {
       const slot = await sessionStore.fetchFromServer(requestSessionId, {
-        provider: sessionProvider as LLMProvider,
-        projectId: selectedProject.projectId,
-        projectPath: selectedProject.fullPath || selectedProject.path || '',
         limit: null,
         offset: 0,
       });

src/components/chat/view/ChatInterface.tsx

@@ -6,7 +6,6 @@ import { useWebSocket } from '../../../contexts/WebSocketContext';
 import PermissionContext from '../../../contexts/PermissionContext';
 import { QuickSettingsPanel } from '../../quick-settings-panel';
 import type { ChatInterfaceProps, Provider  } from '../types/types';
-import type { LLMProvider } from '../../../types/app';
 import { useChatProviderState } from '../hooks/useChatProviderState';
 import { useChatSessionState } from '../hooks/useChatSessionState';
 import { useChatRealtimeHandlers } from '../hooks/useChatRealtimeHandlers';
@@ -223,16 +222,7 @@ function ChatInterface({
   // missed live events, and re-attaches a still-running stream to this socket.
   const handleWebSocketReconnect = useCallback(async () => {
     if (!selectedProject || !selectedSession) return;
-    const providerVal =
+    await sessionStore.refreshFromServer(selectedSession.id);
-      selectedSession.__provider
-      || (localStorage.getItem('selected-provider') as LLMProvider)
-      || 'claude';
-    await sessionStore.refreshFromServer(selectedSession.id, {
-      provider: providerVal as LLMProvider,
-      // Use DB projectId; legacy folder-derived projectName is no longer accepted here.
-      projectId: selectedProject.projectId,
-      projectPath: selectedProject.fullPath || selectedProject.path || '',
-    });
     statusCheckSentAtRef.current.set(selectedSession.id, Date.now());
     sendMessage({
       type: 'chat.subscribe',

src/stores/useSessionStore.ts

@@ -454,9 +454,6 @@ export function useSessionStore() {
   const fetchFromServer = useCallback(async (
     sessionId: string,
     opts: {
-      provider?: LLMProvider;
-      projectId?: string;
-      projectPath?: string;
       limit?: number | null;
       offset?: number;
     } = {},
@@ -511,9 +508,6 @@ export function useSessionStore() {
   const fetchMore = useCallback(async (
     sessionId: string,
     opts: {
-      provider?: LLMProvider;
-      projectId?: string;
-      projectPath?: string;
       limit?: number;
     } = {},
   ) => {
@@ -592,11 +586,6 @@ export function useSessionStore() {
    */
   const refreshFromServer = useCallback(async (
     sessionId: string,
-    _opts: {
-      provider?: LLMProvider;
-      projectId?: string;
-      projectPath?: string;
-    } = {},
   ) => {
     const slot = getSlot(sessionId);
     try {