[voyou]

What do you mean by "trigger the AGPL for all the systems that are network-connected to the AGPL system"?

The AGPL requires that you offer to distribute the source code to derivative works you make of AGPLed code; and it requires that you make that offer to a) people you have distributed binaries to and b) people you permit to access that derivative work over a network.

I guess I can imagine someone arguing that, by integrating Mattermost (for example) with another system, you are thereby giving users of that other system access to your installation of Mattermost, and so you would be required to offer them the source to that installation of Mattermost. Is that what you mean by "trigger the AGPL"?