diff --git a/03-DESIGN/01-to-be/15-the-agent-session.md b/03-DESIGN/01-to-be/15-the-agent-session.md
index c2981a7..db1528b 100644
--- a/03-DESIGN/01-to-be/15-the-agent-session.md
+++ b/03-DESIGN/01-to-be/15-the-agent-session.md
@@ -174,6 +174,18 @@ That a person usually reaches the mesh session through a board is likely and is
 The session is reachable over the broker like everything else; what puts a text box in front of it
 is a different design, and the session does not know which surface asked.
 
+**Several sessions open at once is a property of the surface, not of the sessions.** A board
+showing the mesh's session beside one per node, switchable, leaves *one per node, permanent*
+untouched: each is still one conversation remembering all its callers together. Only *concurrent
+conversations with the same session* would touch ADR 0004, and that is not what is wanted.
+
+Such a surface is a **client** and holds nothing — it sends prompts and shows what the sessions
+themselves remember, which is what keeps it inside `11-a-board.md`'s rule that the board is not a
+second implementation of anything. Prior art to draw the interaction from: impire's *soulstream*
+(already cited in [ADR 0001](../../02-DECISIONS/0001-mesh-brokers-nodes-host-agents-think.md)) and
+`herdrdev/herdr`. **Not yet designed, and not on the path to replacing provisioning** — recorded
+here so the shape is not rediscovered.
+
 ## Consequences
 
 **Two sessions on one node, and no ambiguity.** The control-plane node hosts its own node session