So what exactly is Hilary Benn's new agreement with Jeremy Corbyn?
In return for keeping his post as Shadow Foreign Secretary on Labour's front bench - the two men have come to "an understanding".
I'm told their discussions went from drawing up an "agreement", then to a "six point plan" before finally settling on the "understanding".
But quite what that understanding is, no one seems to know.
Hilary Benn said himself this morning he has not been 'muzzled'.
And his team told me just now that the understanding between Mr Benn and his leader is that he will continue to be as collegiate towards Mr Corbyn.
Jeremy Corbyn's office, however, insists Mr Benn has agreed to be more collegiate than previously (for example over the airstrikes in Syria).
Quite how this will work in practice, we can only guess.
Even a source close to Mr Benn couldn't answer what would happen if there was a disagreement between the two men.
Will Hilary Benn make his differing views clear from the backbenches - before returning to the frontbench?
Or will he have to resign as Shadow Foreign Secretary and speak permanently from the backbenches?
Neither side is able to articulate what the "understanding" is.
But I suspect we won't have to wait too long to find an issue over which they two sides will have to work out how their understanding actually works.