diff --git a/internal/builder/check.go b/internal/builder/check.go
index cc4502f4..51896065 100644
--- a/internal/builder/check.go
+++ b/internal/builder/check.go
@@ -1446,42 +1446,6 @@ func refWords(ref string) string {
 // commitLike is a ref that names a commit.
 var commitLike = regexp.MustCompile(`^[0-9a-f]{7,40}$`)
 
-// replaceGoFiles puts a package's Go files — never its tests — in place of another copy's.
-func replaceGoFiles(from, into string) error {
-	old, err := filepath.Glob(filepath.Join(into, "*.go"))
-	if err != nil {
-		return err
-	}
-	for _, f := range old {
-		if err := os.Remove(f); err != nil {
-			return err
-		}
-	}
-	if err := os.MkdirAll(into, 0o755); err != nil {
-		return err
-	}
-	files, err := filepath.Glob(filepath.Join(from, "*.go"))
-	if err != nil {
-		return err
-	}
-	if len(files) == 0 {
-		return fmt.Errorf("%s holds no Go files", from)
-	}
-	for _, f := range files {
-		if strings.HasSuffix(f, "_test.go") {
-			continue
-		}
-		body, err := os.ReadFile(f)
-		if err != nil {
-			return err
-		}
-		if err := os.WriteFile(filepath.Join(into, filepath.Base(f)), body, 0o644); err != nil {
-			return err
-		}
-	}
-	return nil
-}
-
 // problemLines are the lines of a module check's output that name a problem: not a manifest found ok, not
 // the count, not the closing note.
 func problemLines(s string) []string {
@@ -1794,20 +1758,20 @@ func groupDir(spec CheckSpec, root, tree, repo string) string {
 // to), and false leaves the judge to the rules before it.
 //
 //   - A member with a mesh-controller sibling is judged by the controller built from that sibling's merge (read beside
-//     the check), with the node-engine's validator from the member's own change when it is mesh-host's, else from a
-//     mesh-host sibling's merge, else the one that controller vendors.
-//   - A mesh-controller member is judged by itself, with a mesh-host sibling's validator in place of the one it vendors.
+//     the check), with the validator that controller takes from mesh-sdk at its pin.
+//   - A mesh-controller member is judged by itself, and a mesh-host sibling changes nothing of it: the node-engine holds
+//     no validator any more (issue 1391, novox/hq ADR 0446 clause 5).
 //
 // **The judge is unreviewed code** and is built where nothing the change's script does can reach it: from a copy of the
 // merge made apart from the workspace's tree, with the judge-build environment (JudgeBuildEnv) — a home and Go cache of
 // its own, no global or system git configuration, no version stamping from git — and kept in the judge cache, which no
 // check's container mounts, only for the same inputs: the controller merge and the base commits it was merged onto, the
-// validator's source and commit.
+// controller's pin of the validator.
 func judgeFromTheGroup(ctx context.Context, labelled, run Runner, spec CheckSpec, root, tree string, judged CheckVerdict,
 	said *siblingJudgement, inToolchain func(string, []string, ...string) []string,
 	say func(step, format string, args ...any)) (string, string, bool, error) {
-	controller, host := siblingIn(spec, "mesh-controller"), siblingIn(spec, "mesh-host")
-	var source, validatorDir, from, validator string
+	controller := siblingIn(spec, "mesh-controller")
+	var source, from, validator string
 	var inputs []string
 	merge := func(dir string, s *Sibling) string {
 		return fmt.Sprintf("sibling %s#%d merge %s", s.Repository, s.Number, judged.Beside[dir])
@@ -1815,33 +1779,19 @@ func judgeFromTheGroup(ctx context.Context, labelled, run Runner, spec CheckSpec
 	switch {
 	case len(spec.Group) > 0 && groupDir(spec, root, tree, "mesh-controller") != "":
 		// **A delivery group's composed check is judged by the group's own controller** (novox/hq ADR 0239 §14), whatever
-		// base it merges into: the member that moves mesh-controller, as merged, with the validator of the group's mesh-host member's
-		// merge when it has one, else the one that controller vendors.
-		source, validatorDir = groupDir(spec, root, tree, "mesh-controller"), groupDir(spec, root, tree, "mesh-host")
+		// base it merges into: the member that moves mesh-controller, as merged, with the validator it takes from mesh-sdk at
+		// its pin. A mesh-host member brings no validator (issue 1391), and its tree need hold none.
+		source = groupDir(spec, root, tree, "mesh-controller")
 		from = "the group's own controller, merge " + headAt(ctx, run, source)
-		validator = "the validator the group's controller vendors"
-		if validatorDir != "" {
-			validator = "the group's mesh-host merge " + headAt(ctx, run, validatorDir) + "'s validator"
-		}
+		validator = "mesh-sdk's validator at the pin of the group's controller"
 		inputs = append(inputs, "group member "+spec.Repo+" "+judged.Head+" onto "+judged.Trunk)
 		for _, m := range judged.Members {
 			inputs = append(inputs, "group member "+m.Repo+" "+m.Head+" onto "+m.Trunk)
 		}
-	case spec.Judge == "self" && host != nil:
-		source, validatorDir = tree, filepath.Join(root, "mesh-host")
-		from = "this change's own merge " + judged.Head
-		validator = merge("mesh-host", host) + "'s validator"
 	case spec.Judge != "self" && controller != nil:
 		source = filepath.Join(root, "mesh-controller")
 		from = merge("mesh-controller", controller)
-		switch {
-		case spec.Judge == "validator":
-			validatorDir, validator = tree, "the change's own validator"
-		case host != nil:
-			validatorDir, validator = filepath.Join(root, "mesh-host"), merge("mesh-host", host)+"'s validator"
-		default:
-			validator = "the validator " + merge("mesh-controller", controller) + " vendors"
-		}
+		validator = "mesh-sdk's validator at the pin of " + merge("mesh-controller", controller)
 	default:
 		return "", "", false, nil
 	}
@@ -1851,9 +1801,6 @@ func judgeFromTheGroup(ctx context.Context, labelled, run Runner, spec CheckSpec
 	// A merge made for a check is a new commit each time (its time is in it); what it holds is the same for the same
 	// heads and bases, so the key names those and the trees the judge is built from.
 	inputs = append(inputs, "member "+judged.Head+" onto "+judged.Trunk, "controller tree "+treeAt(ctx, run, source))
-	if validatorDir != "" {
-		inputs = append(inputs, "validator tree "+treeAt(ctx, run, validatorDir))
-	}
 	sum := sha256.Sum256([]byte(strings.Join(inputs, "\n")))
 	key := "siblings-" + hex.EncodeToString(sum[:16])
 	bin := filepath.Join(root, "bin", "judge-of-the-group")
@@ -1867,14 +1814,6 @@ func judgeFromTheGroup(ctx context.Context, labelled, run Runner, spec CheckSpec
 	if err := copyCheckout(ctx, run, source, src); err != nil {
 		return "", "", true, fmt.Errorf("the controller that judges (%s) could not be copied: %w", from, err)
 	}
-	if validatorDir != "" {
-		vendored := filepath.Join(src, "vendor", "github.com", "novox", "mesh-host")
-		for _, pkg := range []string{"validate", filepath.Join("internal", "declaration")} {
-			if err := replaceGoFiles(filepath.Join(validatorDir, pkg), filepath.Join(vendored, pkg)); err != nil {
-				return "", "the validator (" + validator + ") could not be put in the judge: " + err.Error(), true, nil
-			}
-		}
-	}
 	if _, err := labelled(ctx, root, "docker", inToolchain(src, nil,
 		"go", "build", "-o", bin, "./cmd/mesh-controller")...); err != nil {
 		return "", "the controller that judges (" + from + ") does not build with " + validator + ": " + firstLine(err.Error()),
diff --git a/internal/builder/check_test.go b/internal/builder/check_test.go
index b712b25d..3983669f 100644
--- a/internal/builder/check_test.go
+++ b/internal/builder/check_test.go
@@ -3,7 +3,6 @@ package builder
 import (
 	"encoding/json"
 	"os"
-	"path/filepath"
 	"strings"
 	"testing"
 	"time"
@@ -82,26 +81,6 @@ func TestAScriptDeclaresItsToolchain(t *testing.T) {
 	}
 }
 
-// A node-engine change's validator is put in place of the one the judge vendors: its Go files, never its tests.
-func TestTheChangesValidatorReplacesTheVendoredOne(t *testing.T) {
-	from, into := t.TempDir(), t.TempDir()
-	for name, body := range map[string]string{"v.go": "package validate // new", "v_test.go": "package validate"} {
-		if err := os.WriteFile(filepath.Join(from, name), []byte(body), 0o644); err != nil {
-			t.Fatal(err)
-		}
-	}
-	if err := os.WriteFile(filepath.Join(into, "old.go"), []byte("package validate // old"), 0o644); err != nil {
-		t.Fatal(err)
-	}
-	if err := replaceGoFiles(from, into); err != nil {
-		t.Fatal(err)
-	}
-	got, _ := filepath.Glob(filepath.Join(into, "*.go"))
-	if len(got) != 1 || filepath.Base(got[0]) != "v.go" {
-		t.Fatalf("the vendored validator holds %v", got)
-	}
-}
-
 // aJudge is a controller that judges as told: `merge-gate` answers a warning, `module check` refuses a
 // manifest that says it is broken. What the gate layer is tested against without building the real one.
 var aJudge = map[string]string{