diff --git a/apps/x/packages/core/src/auth/oauth-client.ts b/apps/x/packages/core/src/auth/oauth-client.ts
index 762c8aae..0442d7d6 100644
--- a/apps/x/packages/core/src/auth/oauth-client.ts
+++ b/apps/x/packages/core/src/auth/oauth-client.ts
@@ -200,6 +200,11 @@ export async function refreshTokens(
     tokens.scopes = existingScopes;
   }
 
+  // Preserve existing refresh token if server didn't return it
+  if (!tokens.refresh_token) {
+    tokens.refresh_token = refreshToken;
+  }
+
   console.log(`[OAuth] Token refresh successful`);
   return tokens;
 }