The following dialog is taken from the FPS game Crysis Warhead level 7, All the Fury:
Emerson: Psycho, be advised: all JSOC forces are go for withdrawal and re-grouping. We're still not sure the extent of the new threat, but until we have a handle on it we're pulling conventional troops off this meat grinder. The only mission still on the table is yours.
Psycho: Copy, boss. Any news on O'Neill?
Emerson: No. He probably got off the island like everyone else. Those creatures are tearing this place apart.
After consulting several dictionaries, I think the closest sense is a project or undertaking that has been approved, as in Oxford Dictionaries:
Tell them the project is a go.
For anybody who doesn't know, it seems that our move to London is a go, details and timeline to be determined.
The citation says are go, not are a go. Is it correct?
Besides, I think it is a project or undertaking that should act as the subject. I would say it this way:
Withdrawal and re-grouping is a go for all JSOC forces.
Did I get it right? And is my rephrasing acceptable?