the host .ssh is empty, because all it has is the forwarded agent

it turns out the approach outlined in the issue 45 above works just fine, the problem was me not having the local keychain setup properly, sorry about that

so tl;dr: following None and just adding those two extra docker arguments indeed makes the whole pipeline local ssh -> forward -A to server -> start an agent with extra docker args -> agent can correctly use local git credentials work 🙂