backend/app/api/auth.py

@@ -163,11 +163,15 @@ async def google_callback(
     redirect_url = f"{frontend_url}/auth/callback?token={jwt_token}"
     return RedirectResponse(url=redirect_url)
 
+from pydantic import BaseModel
+
+class TokenExchangeRequest(BaseModel):
+    code: str
+    redirect_uri: str
 
 @router.post("/google/token")
 async def exchange_google_token(
-    code: str,
-    redirect_uri: str,
+    request: TokenExchangeRequest,
     db: AsyncSession = Depends(get_db)
 ):
     """
@@ -185,10 +189,10 @@ async def exchange_google_token(
         token_response = await client.post(
             GOOGLE_TOKEN_URL,
             data={
-                "code": code,
+                "code": request.code,
                 "client_id": client_id,
                 "client_secret": client_secret,
-                "redirect_uri": redirect_uri,
+                "redirect_uri": request.redirect_uri,
                 "grant_type": "authorization_code",
             }
         )

frontend/app/auth/callback/page.tsx

@@ -51,7 +51,14 @@ function AuthCallbackContent() {
 
         if (!response.ok) {
           const errorData = await response.json();
-          throw new Error(errorData.detail || "Failed to exchange token");
+          // Handle various error response formats
+          const errorMessage = 
+            typeof errorData.detail === 'string' ? errorData.detail :
+            typeof errorData.error === 'string' ? errorData.error :
+            errorData.message || 
+            JSON.stringify(errorData) || 
+            "Failed to exchange token";
+          throw new Error(errorMessage);
         }
 
         const data = await response.json();
@@ -59,7 +66,8 @@ function AuthCallbackContent() {
         router.replace("/");
       } catch (err: any) {
         console.error("Auth callback error:", err);
-        setError(err.message || "Authentication failed");
+        const msg = err.message || "Authentication failed";
+        setError(typeof msg === 'string' ? msg : "Authentication failed");
         setIsProcessing(false);
       }
     };