diff --git a/lua/pending/sync/gtasks.lua b/lua/pending/sync/gtasks.lua
index a2a6da0..8b918c2 100644
--- a/lua/pending/sync/gtasks.lua
+++ b/lua/pending/sync/gtasks.lua
@@ -436,15 +436,27 @@ local function sync_setup(access_token)
   return tasklists, s, now_ts
 end
 
+local _in_flight = false
+
 ---@param callback fun(access_token: string): nil
 local function with_token(callback)
+  if _in_flight then
+    log.warn('gtasks: operation in progress — please wait')
+    return
+  end
+  _in_flight = true
   oauth.async(function()
     local token = oauth.google_client:get_access_token()
     if not token then
+      _in_flight = false
       log.warn('not authenticated — run :Pending auth')
       return
     end
-    callback(token)
+    local ok, err = pcall(callback, token)
+    _in_flight = false
+    if not ok then
+      log.error('gtasks: ' .. tostring(err))
+    end
   end)
 end