How to build traceability matrix coverage between API endpoints and autotests

The main idea is to build a report that shows autotests-test artefacts coverage. We will look at a detailed way for coverage API endpoints that are stored in Swagger vs automated tests. We will take a look the same idea for BDD testing in such bundle as user story - autotests. 

You have plenty of API automated API tests, don't you? So, we will come to you!