diff --git a/FABRIC.md b/FABRIC.md
index 3fab816..3e54546 100644
--- a/FABRIC.md
+++ b/FABRIC.md
@@ -2053,6 +2053,17 @@ document and committing that amendment as its own item.*
   blocks, and what happens if a patron is selected for reaping while held.
   *Refs:* §8. **This is the largest unresolved design question.**
 
+  > **Hard prerequisite of item 3.1, and its outcome may amend §3.** This item is filed in
+  > Phase 1 alongside questions that have no structural effect, and it is not in that class.
+  > A per-patron exclusivity primitive plausibly needs a held flag or a holder index — a
+  > **ninth wire** in §3's table, in the header item 3.1 builds. Resolve 1.1 after 3.1 and
+  > the cell header gets rebuilt.
+  >
+  > §25.4 already blocks Phase 3 on items 1.1–1.7, so the ordering is right. What was
+  > missing is *why 1.1 specifically* — which is the kind of omission that gets an item
+  > quietly reordered later by someone who does not know what it was holding up. §23.3
+  > reserves 4 header bytes partly against this outcome.
+
 - [ ] **1.2 — The resting floor.** Whether a VM's quota has a floor, and whether it is the
   mass of its pinned patrons (derived) or a constant (tuned). *Refs:* §22.5 #1.
 
@@ -2135,8 +2146,13 @@ document and committing that amendment as its own item.*
 
 *Blocked on Phase 0 complete, and on items 1.1–1.7.*
 
-- [ ] **3.1 — Cell and header.** Define the entry with all eight wires (§3). Validate the
-  64-byte cell by counting real bytes; adjust and record if it does not fit. *Refs:* §23.3.
+- [ ] **3.1 — Cell and header.** Define the entry with all eight wires (§3) — **nine if
+  item 1.1 resolves to a holder index.** Define both members of §3's closed two-valued
+  union: patron header and continuation cell. Validate the 64-byte cell by counting real
+  bytes; adjust and record if it does not fit.
+  **Blocked on:** item 1.1 (may add a wire) and §23.4 #4 (the continuation-cell encoding —
+  contiguous or linked — which sets the mass of every large patron and cannot be guessed).
+  *Refs:* §3, §23.3, §23.4 #4.
 - [ ] **3.2 — Boot-time allocation.** One global cell array, sized from the memory budget,
   before any VM exists. *Refs:* §6, §17.6, §22.3.
 - [ ] **3.3 — Behaviour enumeration and dispatch.** Closed tag set fixed at build time.