Rerun is pretty dope, but I'm not sure how you came to the conclusion that it's the "author's main project"? There is a whole company backing it, with no affiliation that I could find, apart from the author being an occasional contributor?

They mentioned "... and my visualizer tool comes with an MCP server ...", with a link to the rerun project. I guess it makes more sense that his visualizer tool uses rerun...Sorry for the confusion from my side.