diff --git a/modules/mesh-delivery-checker/internal/check/composition_test.go b/modules/mesh-delivery-checker/internal/check/composition_test.go
index bafc264a..174f85be 100644
--- a/modules/mesh-delivery-checker/internal/check/composition_test.go
+++ b/modules/mesh-delivery-checker/internal/check/composition_test.go
@@ -79,6 +79,20 @@ func TestAPassingCheckTakesTheAssignersComposition(t *testing.T) {
 			t.Errorf("with the list not read the composition was handed %s, want none", got)
 		}
 	}
+	// ADR 0635 §3: at a node-engine member's head a list not read fails the composition, naming why, and asks no composer
+	// (a composer handed none would judge no machine and the composition would pass); read, it composes.
+	for _, read := range []bool{false, true} {
+		b.ex.SeatList = fakeSeatList{read: read}
+		asked := len(f.asked)
+		hv := b.judge(t, caseOf(t, pullOf(repoA, 7, head1), pullOf(nodeEngineRepo, 3, head2))).Verdict
+		switch {
+		case !read && (hv.State != meshdeliverycheckerclient.VerdictFail || hv.Composition == nil || hv.Composition.State != meshdeliverycheckerclient.CompositionFail ||
+			!strings.Contains(hv.Composition.Words, "seat list") || len(f.asked) != asked):
+			t.Errorf("at a node-engine head with the list not read: verdict %+v, composition %+v, asked %d more; want a failed composition naming the seat list, no ask", hv, hv.Composition, len(f.asked)-asked)
+		case read && (hv.Composition == nil || hv.Composition.State != meshdeliverycheckerclient.CompositionPass || len(f.asked) != asked+1):
+			t.Errorf("at a node-engine head with the list read: composition %+v, want the composer's pass", hv.Composition)
+		}
+	}
 	b.ex.SeatList = nil
 	f.asked, f.seats = f.asked[:1], f.seats[:1]
 	// ADR 0548 §5: a carry whose fingerprints did not change keeps the composition it passed and asks the assigner nothing.
diff --git a/modules/mesh-delivery-checker/internal/check/judge.go b/modules/mesh-delivery-checker/internal/check/judge.go
index f138bddc..10680a69 100644
--- a/modules/mesh-delivery-checker/internal/check/judge.go
+++ b/modules/mesh-delivery-checker/internal/check/judge.go
@@ -406,9 +406,17 @@ func (st *state) composed(ctx context.Context, v *meshdeliverychecker.VerdictsBy
 	// The composer of a node-engine member's head composes against the check's seat list, the judge's (ADR 0635 §1, ADR 0636
 	// §4); only a list the reader read is handed: the heads' alone are no list, and the composer then judges no machine.
 	st.c.Seats = nil
-	if seats, err := st.checkSeats(ctx); err != nil {
-		st.c.note("the composition is given no seat list: " + err.Error())
-	} else if seats.listed {
+	seats, serr := st.checkSeats(ctx)
+	switch head := composerHead(st.c); {
+	case serr != nil && head != "":
+		// A composition at a node-engine member's head that cannot read the seat list it needs fails, naming why, rather than
+		// passing with no machine judged (ADR 0635 §3, ADR 0636 §1).
+		withComposition(v, meshwants.CompositionsByGroupHeadsValue{Group: st.c.Group, Heads: st.c.Heads, State: meshdeliverycheckerclient.CompositionFail,
+			Sdk: head, Words: "the composer at the node-engine's head " + head + " cannot be given the seat list it composes against: " + serr.Error()})
+		return
+	case serr != nil:
+		st.c.note("the composition is given no seat list: " + serr.Error())
+	case seats.listed:
 		st.c.Seats = seats.defs
 	}
 	comp, err := st.j.Compositions.Compose(ctx, st.c, st.tags.goPackages)
diff --git a/sdk/composer/composer.go b/sdk/composer/composer.go
index 685fa51d..5990fa29 100644
--- a/sdk/composer/composer.go
+++ b/sdk/composer/composer.go
@@ -63,9 +63,9 @@ type Request struct {
 	// 0578 §5, ADR 0606 §4); the composer does not read them. Nil is no list at hand, and the judge judges no name; an
 	// empty list is a list, and every name is unknown to it.
 	Packages []string `json:"packages,omitzero"`
-	// Seats are the seat definitions the judge judges against, as the asker's seat list reader holds them (the definitions of the
-	// seat mesh-catalog, resolved), raw so that this package names no seat (ADR 0635 §4, ADR 0636 §1). The judge reads them; the
-	// composer does not. None is no list at hand: the judge then judges against the list its process was given.
+	// Seats are the seat definitions the judge judges and the composer composes against, as the asker's seat list reader holds
+	// them (the definitions of the seat mesh-catalog, resolved), raw so that this package names no seat (ADR 0635 §4, ADR 0636
+	// §1). The judge and the composer read them. None is no list at hand: a composer handed none judges no machine (ADR 0636 §1).
 	Seats []json.RawMessage `json:"seats,omitempty"`
 }