You can automatically fire up the mcp or anything you want with s3d and have it closed when s3d goes down or vice versa:

just create a shellscript at position /etc/s3drc or ~/.s3drc, for example have it starting the mcp. Don't forget to toggle it executable (chmod 755 or so).

When s3d starts, it will look for ~/.s3drc or /etc/s3drc (in this order), and will start it along with the server. E.g. when you log out off your mcp, the s3d server is shut down too.

You can disable this behavior with s3d --no-rc

For example my .s3drc looks like this:

$ cat ~/.s3drc 
 #!/bin/sh
cd ~/msrc/s3d/apps/dot_mcp/
./dot_mcp