Install the attached tool_demo.zip plugin which provides a simple external function without specifying its methodname in db/services.php TEST Run the demo plugin's tests and make sure they pass (i.e. external function was correctly registered using default methodname). vendor/bin/phpunit -c admin/tool/demo/ Modify the file admin/tool/demo/db/services.php and use some explicitly declared methodname, e.g.: 'tool_demo_get_current_time' => [ 'classname' => '\tool_demo\external\get_current_time', 'methodname' => 'run', // ... Modify the file demo/classes/external/get_current_time.php and change the name of all three methods accordingly. In this example, we would replace 'execute' prefix with 'run'. Increase the version number in the tool_demo plugin's version.php and upgrade the site. TEST Run the demo plugin's tests again and make sure they still pass (i.e. developers can still provide explicit custom name). Modify the file admin/tool/demo/db/services.php and remove the methodname property that you added. Modify the file demo/classes/external/get_current_time.php and revert the method names back to using the "execute" prefix. Increase the version number in the tool_demo plugin's version.php and upgrade the site. TEST Run the demo plugin's tests again and make sure they still pass (i.e. the methodname can be removed from the file if the class uses default names).