@durval
I thought a little more about your use case and I think I have an idea how pulling might be implemented in general. This needs two flags/settings: --config-from rc://host:port pointing to another rclone instance with --rc enabled like above.
But additionally we need --config-transfer-filter section/value,... which defaults to nothing. User will set it knowing what they do so they guarantee that requested value is valid at all times.
When a value refresh is requested by backend (usually by oauth task), rclone will unconditionally do the pull request, retry it --low-level-retry times, return failure if any, on success return value to backend and update it in local config. No arbitrage, no attempts to check token expiry field, no nothing.
I can implement this logic in one of my betas. If it works for you or another volunteer I can submit it as PR for review by @ncw. However, for docker swarm (my use case) it's useless as there is no primary volume accessor, they are ever rotating.
Again, current jotta backend behavior (stall forever in token refresh) must be considered a bug and reviewed by @buengese. Please submit a request on github with due details.