@nobodyinperson section 13 of AGPL says that if users can interact with a modified version of an AGPL program, then you had to distribuite under AGPL also the modified code.

But then we must define "modified version of a (A)GPL program"...

Using git-anex inside a shell script or a bigger service, is usually freely permitted, because it is covered by " This License explicitly affirms your unlimited permission to run the unmodified Program.".

But if the shell script or the bigger service is adding more functionanilities to git-anex, that should be considered as part of git-anex? Are you still an user of git-anex program/service, or are you extending it, circumventing the (A)GPL? Problably only a judge can decide this.

Usually if you are using git-anex like a service, then you can use it freely, and the larger service is not obliged to be under AGPL, because you are only an user of git-anex. Every time you improve git-anex, for working better inside your larger service, then you had to release only these improvements to git-anex, under AGPL.

But the line between using a service, and extending it, can be blur in some cases.

Note that in some cases, you can also produce a larger service, compiling git-anex code inside your "aggregate code", without the need to relaese the full "aggregate code" under (A)GPL. It is in the final part of section 5, but these definitions are not so much clear, IMHO.