I do this a lot and you have to be really careful to clean these up or qualify/steer agents around them. They’ll often be very emphatically confident about some assumption or implication they made, and if another agent stumbles upon them they’ll get mislead.

They don’t really know what they’re handing off or what you’re trying to actually do, so in a sense it’s not a grounded task for them. Actually, if you think about it, any scenario in which a handoff doc might be valuable is probably almost always better as a subagent thread, because you are paying the same amount of read/write tokens but you can clear things up synchronously.

I’ve found two-way message passing (each get their own write file, they read each others) to work much better because the communication is more grounded in actual coordination/work. You can also give each an inbox so that multiple can write to it. If you do the “progressive disclosure” right it scales subquadratically because they only read/write to others when it’s relevant to what they’re working on.

But IMO “write a handoff” is a trap, as a human you end working in some kind of robot-graffiti codebase full of junk, and it ends up being a booby trap for agents literally within days.