Hi, I checked the Meraki API doc on my Dashboard (help > API docs), there is no API call that can get the mesh routes so this is not supported at the moment.
The API docs get updated whenever there is a new feature added so I would recommend checking it from time to time. Also, the Dashboard has a "Make a wish" button on the lower right corner of your screen which you can use to submit this as a feature request.
https://documentation.meraki.com/zGeneral_Administration/Other_Topics/Make_a_Wish
Please hit kudos if you found this post helpful and/or click "accept as solution" if this solved your problem.
