ADK seems like a better thought through SDK family, I use Go, Py is most mature, also TS and Java. The docs still need a lot of work to cover all the languages, it's pretty hit or miss right now, but one can also have a coding agent look at the source and an example for another language. Notably to your complaint, I have a coding agent that if the client drops, the llm/agent keeps working in the background. This requires it being set up as a server, which implies tool calls happen there instead of where the client is. I used Dagger as the "sandbox" more for easy time traveling / forking than being a sandbox. The well designed interfaces that allow custom implementations are what hooked me on ADK.

https://adk.dev/get-started/about/ | https://github.com/google/adk-go