diff --git a/docs/LANES/ROUND26_INSTRUCTIONS.md b/docs/LANES/ROUND26_INSTRUCTIONS.md
index bcdf81c..d436517 100644
--- a/docs/LANES/ROUND26_INSTRUCTIONS.md
+++ b/docs/LANES/ROUND26_INSTRUCTIONS.md
@@ -95,10 +95,34 @@ hold, on three rungs:
    distinctness gate wants a crowd check at a stocked shop (patronage at Monster Robot on a
    Saturday feels like a D flourish, not a requirement).
 
+## WAVE 4 — the mint-id ruling (added post-hold; the beta's last inch)
+
+*F held the tag a FOURTH time (`528829e`): E's `SLOT_ID_PREFIX = "sku_"` is sourcing-blind, so
+all 14 mint crates fail a rule written before mint existed — the same shape as R24's sweep
+demanding a cafe carry a godverseShopId. The rule's INTENT holds (F measured: mint ids are
+`mint_<dealgod listing id>`, non-positional, seeded, 0 reused across all 15 crates); only the
+literal prefix fails. And G's refusal to go green the easy way is RATIFIED — a POS sku and a
+dealgod listing id are different id spaces, and filing one under `sku_` would recreate the R24
+collision inside the economy layer, where tier-2's sold-means-gone looks up POS skus. The
+prefixes ARE the namespace fence.*
+
+1. **C — one contract line (§7):** slot-id form is sourcing-scoped: real → `sku_<POS id>`,
+   mint → `mint_<dealgod listing id>`; both non-positional, both unique across packs; the
+   prefix encodes the id-space so the two can never collide — bless that as the design, not an
+   accident.
+2. **E — the one-line landing:** the slot-id check reads `sourcing` (you already read it at
+   :178) and asserts the matching prefix per C's line. Real crate: `sku_`. Mint crate: `mint_`.
+   Anything else, or a cross-wearing crate: FAIL.
+3. **F — re-run atlas-QA, then the tag:** `qa.sh --strict --matrix` (should flip 6/1/0 →
+   7/0/0), tag **`v5.0-beta`**, push. Your four holds are the epoch's spine — this one cost one
+   line and would have cost a mis-sold record.
+
 ## Laws
 
-Charter v5 + vacuous-gate + the id-namespace note above. Golden discipline: no town-cache
-changes this round → no golden moves (mint atlases are `stock_godverse/**` files, outside every
+Charter v5 + vacuous-gate + the id-namespace note above (now with its economy-layer corollary:
+**id prefixes are namespace fences** — `sku_` is the POS space, `mint_` is the dealgod-listing
+space, and no gate or lookup may treat them as one). Golden discipline: no town-cache changes
+this round → no golden moves (mint atlases are `stock_godverse/**` files, outside every
 golden). No server code — tier 2 stays design until the beta ships and the v5.0 round charters
 it against the ratified G3.