Based on [1] it sounds like even if you "link" to AGPL licensed code over a network, unmodified or not, it would require you to also license your own code as AGPL? That sounds pretty far reaching, if I'm reading it correctly.
Basically, if you ever need to use agpl stuff, do not embed or add your proprietary ip to a modified version. Use a sidecar. Only embed features you don’t care about.
I don't think that essay supports what you said. (It's incredibly well written by the way, thanks for linking it.) Near the end it asks:
> If you build a larger web service by combining network services that call each other over HTTP, rather than libraries or snippets of code linked or pasted together, does “Corresponding Source” include the source for those other services? What if each service is containerized, encapsulated in its own operating system? Do those operating systems count as “System Libraries” or “generally available programs” shield the application code they run?
Note that the author is asking a question here. It's not entirely clear (AFAIK, IANAL, etc) what precisely constitutes "linking" when it comes to the (A)GPL.
A thought experiment. Evil Corp takes a GPL licensed program and modifies it to communicate via file descriptors instead of linking with it at compile time and directly calling its functions. They proceed to distribute a separate proprietary product that makes use of the GPL program for many of its core functions. They claim that this isn't a violation of the GPL because they haven't "linked" with any GPL'd code. This is clearly a violation of the spirit of the GPL, but is it a violation of the letter?
To comply with the license, the Evil Corp would be required to share their modifications giving anybody who sees this as their market advantage the ability to do exactly the same thus diminishing the advantage. The Evil Corp would not be required to share the code which talks to the modified GPL'd library.
That's the spirit of this license and everything is working as intended.
But it's a good line of thought. Here's another thought experiment. When compiling say golang or Rust program, all dependencies end up being compiled into a single standalone binary. If a dependency of a dependency pulls in an unmodified GPL module, what impact does it have on our resulting binary? The common understanding is: if we're asked to share the code of the GPL dependency, we can share the original unmodified dependency and we're not required to share our code using the dependency.
Until we're proven otherwise, we should stick to that common understanding.
Basically, if you ever need to use agpl stuff, do not embed or add your proprietary ip to a modified version. Use a sidecar. Only embed features you don’t care about.