diff --git a/packages/polyfill/src/emulated-verifier/read-filter.ts b/packages/polyfill/src/emulated-verifier/read-filter.ts
index efe855f..b3a7511 100644
--- a/packages/polyfill/src/emulated-verifier/read-filter.ts
+++ b/packages/polyfill/src/emulated-verifier/read-filter.ts
@@ -352,12 +352,16 @@ function filteredDescriptor(
  * cases leak is not a boundary.
  *
  * ── And `get` is not the only door ────────────────────────────────────────
- * Three traps answer the same question and all three have to give the same answer:
+ * Four traps answer the same question and all four have to give the same answer:
  * `get`, `getOwnPropertyDescriptor` (which `Object.keys`, a spread, `JSON.stringify` and
  * any console inspection go through, WITHOUT touching `get`) and, on the array form,
  * `has` and `ownKeys`. Each of them was forwarding to the target while `get` filtered.
- * They are wired to one `read` function below rather than to three copies of the rule,
- * because a boundary made of parallel switch statements is a boundary that drifts.
+ * `get` and `getOwnPropertyDescriptor` are wired to one `read` function below rather than
+ * to two copies of the rule; `has` and `ownKeys` answer positions rather than values, so
+ * they do not go through `read` but project from the same `kept` set it reads - which is
+ * what makes the four agree. Not one funnel, then, but one SOURCE: a boundary made of
+ * parallel switch statements is a boundary that drifts, and so is a header that claims a
+ * funnel it does not have.
  *
  * ── The default: DECIDED, or refused ─────────────────────────────────────
  * Every member this file serves is named below. Anything else refuses, whatever its type.
@@ -574,7 +578,10 @@ export function makeReadFilteredView<S extends object>(set: S, caps: CapRegistry
     // three different ways: a mutation may not reach past what the view shows, and may not
     // hand back what the view hides.
     //
-    // ALL THREE ARE GATED ON `keep`, and that is the arbitration rather than an accident.
+    // ALL THREE ARE GATED, on the same question asked of the item, and that is the
+    // arbitration rather than an accident. `delete` and `clear` ask `keep` - may the
+    // holder READ this item - while `add` asks the stricter `writable`, because planting
+    // an item means naming a document the holder HOLDS, which reading one does not.
     // `delete` and `clear` were gated first and `add` was not, which made the rule above
     // true by coincidence: the ungated `add` MANUFACTURED the very state the other two
     // then handled partially - a holder can plant an item into a document it cannot read,