Can't you use a personal mobile device with a 4G connection to access a knowledge database outside the firewall, without moving any data across your employers network? As long as the data you wish to read/write is not sensitive in itself, and it's mostly just plaintext notes that you can read/write from any device, I don't see the issue with that.

Secure physical sites (e.g. some military bases) may require you to place personal electronics in a lockable cabinet. You have to use a paper notepad if you don't have a device certified by the local security team. Using a non-certified device can result in being evicted or prosecuted.

Doesn’t the Language Server Protocol already do this, just via JSON instead of XML? I believe at least some LSP backends (e.g. clangd) just reuse a compiler AST and feed the data to your editor?