Three agents submit three pieces, each looking fine. You assemble them and it surfaces: agent A returns dates as dd/mm, agent B reads them as mm/dd; agent C assumed a field is always present, while A lets it be empty. No piece is "wrong" within its scope. They're wrong where they meet — and no one owns that meeting point.
This is the most overlooked step in orchestration: everyone focuses on "splitting up," forgetting that "joining back" is where the truth shows itself.
01Gathering needs an owner, not just adjacency
✕ Set side by side
✓ Reconcile with an owner
The hinge is the word decide. Gathering isn't a mechanical stitch-the-pieces-together — it's where you (or an agent given exactly the gathering role) check each piece against the shared contract, find where they argue, and decide which piece yields. A conflict with no one to decide it doesn't vanish — it just sinks, waiting to blow at the real join.
02The gather point is also the check point
A convenience: the gather point is the natural place to apply the "verify before you trust" gate. All three agents may report "done" — but each one's "done" is only done-within-its-role. The real done is when the pieces join and run together, and that can only be proven at the gather step.
So don't treat gathering as a tidy-up tacked on at the end. It's the step where the whole team's work either becomes something usable, or reveals itself as a pile of individually-right. One gather point, one decider, one check against the shared contract — that's what turns "many agents" from a mess into a machine.