Almost more interesting than what Corbyn and the PM said to each other this afternoon was who accompanied the Labour leader to the meeting.
He was joined by his chief of staff Karie Murphy and his director of strategy Seumas Milne (as well as the chief whip Nick Brown) but not by his Brexit secretary Keir Starmer.
Why does that matter?
In the battle over whether Labour should ever back a Brexit referendum or People's Vote, Murphy and Milne are implacably opposed, and Starmer is battling to keep that option alive.
So it matters that in choosing to explain what kind of Brexit deal Labour would support, Corbyn was accompanied by the two influential aides who are convinced that Labour should deliver Brexit and not ask the views of the people again.
This was a signal, his colleagues say, of Corbyn's own clear preference to avoid another referendum.
What also matters is that Corbyn felt - I am told - that the meeting was more than a going through the motions, that the Prime Minister genuinely listened and probed, as he and his colleagues outlined their plan for membership of the customs union, partial membership of the EU's single market, and further protections for workers' rights.
In terms of the technical nitty gritty, Corbyn and team said they wanted dynamic alignment with the EU on employment regulations - as opposed to the standstill written into the so-called backstop - and non-regression or a standstill on state aid rules.
This seems to me all of a piece with a pincer movement by Milne and Murphy with Len McCluskey, general secretary of the Unite union, to try to engineer a Brexit deal before 29 March that Labour could officially fall in behind - since McCluskey too, who is close to Corbyn, is set against a referendum.
McCluskey, for example, yesterday met the business secretary Greg Clark - who as it happens is on my show tonight - to discuss legislation to protect and extend workers' right after Brexit.
And tomorrow more junior officials from Unite, the TUC, the GMB and Unison will meet Sarah Healey, the director of economic and domestic affairs at the Cabinet Office and Chris Thompson from the business department to take the agenda forward on what the government can do to secure trade union support for Brexit.
For what it's worth, my understanding is that Corbyn sees the failure to secure a majority yesterday of the Cooper and Grieve motions - and Labour's own one, which explicitly mentions the possibility of a referendum - as proof that MPs really don't want a People's Vote.
Even more striking is that those close to Labour's leader tell me they can indeed envisage a moment in the coming weeks when it will be official Labour policy to vote for a Brexit plan.
Those at the top of Labour, and in the grassroots, who want a referendum should fear they are being properly outmanoeuvred.