To be tested   in Moodle 3.5 and master. Prerequisites You need the test tool provider site to be able to communicate with your Moodle instance. You can use ngrok for this. Test On a remote 'consumer' Moodle system: Find/create a course with a non-empty value for the Course summary. Enter the course as a Teacher Turn editing on Use the "Add an activity or resource" link to add an External tool Enter an Activity name Enter a Tool URL of "https://lti.tools/saltire/tp" Enter a value of "desc=$Context.longDescription" inside the Custom parameters field (under "Show more ...") Click on "Save and display". Ignore the failed verification message, click on "Message Parameters" and look for the custom_desc entry Expected result:  Check that the custom_desc parameter value is the course summary (text only). Important : Before the fix the value will be empty (and a PHP error will be generated), after the fix the value will be the course description (course summary).