diff --git a/lua/cp/async/setup.lua b/lua/cp/async/setup.lua
index 5e899a3..9db5138 100644
--- a/lua/cp/async/setup.lua
+++ b/lua/cp/async/setup.lua
@@ -98,7 +98,7 @@ function M.setup_problem_async(contest_id, problem_id, language)
     state.set_test_cases(nil)
   end
 
-  vim.cmd('silent only')
+  vim.cmd.only({ mods = { silent = true } })
   state.set_run_panel_active(false)
   state.set_contest_id(contest_id)
   state.set_problem_id(problem_id)
diff --git a/spec/async_integration_spec.lua b/spec/async_integration_spec.lua
index 2155ff6..fd4b5f8 100644
--- a/spec/async_integration_spec.lua
+++ b/spec/async_integration_spec.lua
@@ -75,11 +75,12 @@ describe('async integration', function()
       end,
     }
 
-    vim.cmd = function() end
-    vim.cmd.e = function() end
-    vim.cmd.only = function() end
-    vim.cmd.startinsert = function() end
-    vim.cmd.stopinsert = function() end
+    vim.cmd = {
+      e = function() end,
+      only = function() end,
+      startinsert = function() end,
+      stopinsert = function() end,
+    }
     vim.api.nvim_get_current_buf = function()
       return 1
     end
diff --git a/spec/async_scraper_spec.lua b/spec/async_scraper_spec.lua
index e0c2836..3a9f31a 100644
--- a/spec/async_scraper_spec.lua
+++ b/spec/async_scraper_spec.lua
@@ -26,7 +26,7 @@ describe('cp.async.scraper', function()
       end,
     }
 
-    vim.system = function(cmd, _, callback)
+    vim.system = function(cmd, opts, callback)
       local result = { code = 0, stdout = '{}', stderr = '' }
       if cmd[1] == 'ping' then
         result = { code = 0 }
@@ -36,7 +36,17 @@ describe('cp.async.scraper', function()
         result.stdout =
           '{"success": true, "tests": [{"input": "1 2", "expected": "3"}], "timeout_ms": 2000, "memory_mb": 256.0, "url": "https://example.com"}'
       end
-      callback(result)
+
+      if callback then
+        callback(result)
+      else
+        -- Return object with :wait() for sync calls
+        return {
+          wait = function()
+            return result
+          end,
+        }
+      end
     end
 
     vim.fn.mkdir = function() end
diff --git a/spec/async_setup_spec.lua b/spec/async_setup_spec.lua
index 984ac20..ccb41bc 100644
--- a/spec/async_setup_spec.lua
+++ b/spec/async_setup_spec.lua
@@ -69,11 +69,12 @@ describe('cp.async.setup', function()
       end,
     }
 
-    vim.cmd = function() end
-    vim.cmd.e = function() end
-    vim.cmd.only = function() end
-    vim.cmd.startinsert = function() end
-    vim.cmd.stopinsert = function() end
+    vim.cmd = {
+      e = function() end,
+      only = function() end,
+      startinsert = function() end,
+      stopinsert = function() end,
+    }
     vim.api.nvim_get_current_buf = function()
       return 1
     end
diff --git a/spec/spec_helper.lua b/spec/spec_helper.lua
index db826d7..01c2a04 100644
--- a/spec/spec_helper.lua
+++ b/spec/spec_helper.lua
@@ -35,10 +35,14 @@ local function setup_vim_mocks()
   if not vim.cmd then
     vim.cmd = {}
   end
-  vim.cmd.e = function() end
-  vim.cmd.only = function() end
-  vim.cmd.split = function() end
-  vim.cmd.vsplit = function() end
+  vim.cmd = {
+    only = function() end,
+    e = function() end,
+    split = function() end,
+    vsplit = function() end,
+    startinsert = function() end,
+    stopinsert = function() end,
+  }
   if not vim.system then
     vim.system = function(_)
       return {