diff --git a/cmd/mesh-host/no_check_script_test.go b/cmd/mesh-host/no_check_script_test.go
new file mode 100644
index 0000000..9861c80
--- /dev/null
+++ b/cmd/mesh-host/no_check_script_test.go
@@ -0,0 +1,15 @@
+package main
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+// The checker runs gofmt, go vet and both test levels by Go's convention, and the build module starts the bus the
+// integration level needs (novox/hq ADR 0529): no script of the repository's own runs beside them.
+func TestTheRepositoryHoldsNoCheckScript(t *testing.T) {
+	if _, err := os.Stat(filepath.Join("..", "..", "merge-check.sh")); err == nil {
+		t.Fatal("merge-check.sh is back: the checker's levels run the tests")
+	}
+}
diff --git a/cmd/mesh-host/vaultbox_nats_test.go b/cmd/mesh-host/vaultbox_nats_test.go
index ddb83c6..719040c 100644
--- a/cmd/mesh-host/vaultbox_nats_test.go
+++ b/cmd/mesh-host/vaultbox_nats_test.go
@@ -3,7 +3,7 @@ package main
 // Issue 755's proof on a real bus (novox/hq ADR 0349 §16): a core credential the vault sealed to this machine crosses
 // the bus inside the declaration, which the controller carries and cannot open, and this engine opens it with its
 // sealing key and writes the value. A listener on every subject keeps every byte that crossed; the value is never
-// among them. Run against the throwaway bus merge-check.sh starts (MESH_TEST_NATS).
+// among them. Run against the throwaway bus the build module starts for the integration level (MESH_TEST_NATS).
 
 import (
 	"context"
diff --git a/internal/apply/judge_directories_test.go b/internal/apply/judge_directories_test.go
index 950d50c..8b11e7e 100644
--- a/internal/apply/judge_directories_test.go
+++ b/internal/apply/judge_directories_test.go
@@ -11,7 +11,9 @@ import (
 
 // The read-only judgement of a node's directories (novox/hq issue 358): one line each — placed, would be refused
 // naming the link and who could replace it, or not there yet (placed: an apply makes it) — and nothing made or
-// changed.
+// changed. Who could replace the link is "every account", "the account X" or "the group X", by the account and the
+// directories the test runs as: the checker's isolated step runs as the account nobody, which owns / there (issue 1919,
+// R4g), so the test demands a who in any of the forms couldReplace and linkReplacer produce, not "every account" alone.
 func TestJudgeDirectoriesSaysWhatTheWalkWouldRefuseAndChangesNothing(t *testing.T) {
 	base := t.TempDir()
 	plain := filepath.Join(base, "plain")
@@ -39,7 +41,8 @@ func TestJudgeDirectoriesSaysWhatTheWalkWouldRefuseAndChangesNothing(t *testing.
 		t.Errorf("a directory the walk reaches is not said placed: %q", said)
 	}
 	if !strings.Contains(lines[2], "would be refused") || !strings.Contains(lines[2], filepath.Join(base, "linked")) ||
-		!strings.Contains(lines[2], "every account") {
+		!(strings.Contains(lines[2], "every account (") || strings.Contains(lines[2], "the account ") ||
+			strings.Contains(lines[2], "the group ")) {
 		t.Errorf("the linked directory is not said refused naming the link and who: %q", lines[2])
 	}
 	if _, err := os.Stat(filepath.Join(base, "missing")); !os.IsNotExist(err) {
diff --git a/internal/apply/library_test.go b/internal/apply/library_test.go
index 11349a2..73fa166 100644
--- a/internal/apply/library_test.go
+++ b/internal/apply/library_test.go
@@ -11,6 +11,7 @@ import (
 	"path/filepath"
 	"strconv"
 	"strings"
+	"syscall"
 	"testing"
 	"time"
 
@@ -23,6 +24,23 @@ import (
 // The engine's half of ADR 0328's checks (novox/hq ADR 0328, "How it is checked", issue 567). The engine runs as
 // root; a test may not, and a non-root test gives its folders a group it is in itself.
 
+// canSetGroups skips aloud a test that gives a folder a group when this step cannot. **A step that cannot set a folder's
+// group judges nothing here** (issue 1919, R4g): the checker runs the tests in the build module's isolation, a user
+// namespace that maps no group but the step's own, so a chown to any other group is refused (EINVAL or EPERM). A test that
+// sets a group calls it first: the probe gives a file of the test's own that group, and when it is refused the test skips
+// aloud; outside such an isolation it runs and is judged.
+func canSetGroups(t *testing.T, gid int) {
+	t.Helper()
+	probe := filepath.Join(t.TempDir(), "probe")
+	if err := os.WriteFile(probe, nil, 0o600); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.Chown(probe, -1, gid); errors.Is(err, syscall.EINVAL) || errors.Is(err, syscall.EPERM) {
+		t.Skipf("NOT JUDGED: this step cannot set a folder's group (a user namespace maps only its own account, as the "+
+			"checker's isolated step does): %v; issue 1919", err)
+	}
+}
+
 // testGID is a group the test may give its folders: any number as root, else one of its own added groups that is
 // no root group's.
 func testGID(t *testing.T) int {
@@ -121,6 +139,7 @@ func statOf(t *testing.T, path string) unix.Stat_t {
 // those folders alone, never what is in them; owner, owner's and others' bits unchanged.
 func TestALibraryIsKeptInItsGroup(t *testing.T) {
 	gid := testGID(t)
+	canSetGroups(t, gid)
 	libraries(t, nil, nil)
 	root := filepath.Join(t.TempDir(), "media")
 	if err := os.Mkdir(root, 0o755); err != nil {
@@ -170,6 +189,7 @@ func TestALibraryIsKeptInItsGroup(t *testing.T) {
 // Row 9: a missing sub-path is made with the root's owner, the library's group, group rwx and setgid.
 func TestAMissingSubPathIsMadeAsTheRootIs(t *testing.T) {
 	gid := testGID(t)
+	canSetGroups(t, gid)
 	libraries(t, nil, nil)
 	root := filepath.Join(t.TempDir(), "media")
 	if err := os.Mkdir(root, 0o751); err != nil {
@@ -226,6 +246,7 @@ func TestARootThatHoldsDataWaitsForTheOperatorsWord(t *testing.T) {
 // (the act's ask, internal/link); an undeclared library refused; a walk over its bound goes on from its cursor.
 func TestTheTakeActSetsTheGroupUnderTheRoot(t *testing.T) {
 	gid := testGID(t)
+	canSetGroups(t, gid)
 	libraries(t, nil, nil)
 	base := t.TempDir()
 	root := filepath.Join(base, "media")
@@ -512,6 +533,7 @@ func TestNoLibraryGroupIsRoot(t *testing.T) {
 // A library's filesystem that cannot be named this time is unknown, never a move; another filesystem at the root is.
 func TestALibraryNotNamedIsUnknownAndAnotherFilesystemIsAMove(t *testing.T) {
 	gid := testGID(t)
+	canSetGroups(t, gid)
 	base := t.TempDir()
 	pool := filepath.Join(base, "pool")
 	root := filepath.Join(pool, "media")
@@ -650,6 +672,7 @@ func TestALibraryIsNeverTheMachinesOwnTree(t *testing.T) {
 // and sample all in shape are kept; once taken, never asked again on that filesystem.
 func TestARootInShapeWithDataBelowNotInTheGroupWaits(t *testing.T) {
 	gid := testGID(t)
+	canSetGroups(t, gid)
 	libraries(t, nil, nil)
 	root := filepath.Join(t.TempDir(), "media")
 	movies := filepath.Join(root, "movies")
@@ -699,6 +722,7 @@ func TestARootInShapeWithDataBelowNotInTheGroupWaits(t *testing.T) {
 // file never keeps its setgid bit once regrouped.
 func TestRootsLinkedFilesAreLeftAndSetgidIsNeverKept(t *testing.T) {
 	gid := testGID(t)
+	canSetGroups(t, gid)
 	f, err := os.CreateTemp(t.TempDir(), "file")
 	if err != nil {
 		t.Fatal(err)
@@ -729,6 +753,7 @@ func TestRootsLinkedFilesAreLeftAndSetgidIsNeverKept(t *testing.T) {
 // waits for the operator's word as the root would, and nothing of it is changed; an empty one is kept.
 func TestASubPathHoldingOldDataWaitsForTheOperatorsWord(t *testing.T) {
 	gid := testGID(t)
+	canSetGroups(t, gid)
 	libraries(t, nil, nil)
 	root := filepath.Join(t.TempDir(), "media")
 	if err := os.Mkdir(root, 0o755); err != nil {
@@ -795,6 +820,7 @@ func TestAnApplyDoesNotWaitForATakeWalk(t *testing.T) {
 // the root alone, says whether the data is the library's already (§7).
 func TestTheSampleBeneathARootInShapeIsJudged(t *testing.T) {
 	gid := testGID(t)
+	canSetGroups(t, gid)
 	libraries(t, nil, nil)
 	root := filepath.Join(t.TempDir(), "media")
 	if err := os.MkdirAll(filepath.Join(root, "old"), 0o755); err != nil {
diff --git a/internal/bootstrap/builder_test.go b/internal/bootstrap/builder_test.go
index 6127d47..eb109a2 100644
--- a/internal/bootstrap/builder_test.go
+++ b/internal/bootstrap/builder_test.go
@@ -150,13 +150,19 @@ func TestAForgeManifestTheCatalogueDoesNotHaveIsNamed(t *testing.T) {
 
 // theCataloguesModule is a module's own manifest, never a copy: the clone beside a merge check (MESH_CHECK_BESIDE), where it
 // must be; else a checkout beside this one; else the test skips aloud. The catalogue holds it, but for the build agent,
-// which moved whole into the controller's repository (ADR 0420, issue 1019, issue 1151) and is read from there.
+// which moved whole into the controller's repository (ADR 0420, issue 1019, issue 1151) and was read from there.
+//
+// **The build agent is not there any more** (R4g, ADR 0524 section 5): the group deletes it from the controller with the seat
+// node-build-agent. Genesis still installs it as a new mesh's builder, and where genesis gets a builder instead is issue
+// 1152's decision, queued out of that milestone. Until then every test whose subject is the build agent's manifest skips
+// aloud here, and is judged again with issue 1152.
 func theCataloguesModule(t *testing.T, module string) []byte {
 	t.Helper()
-	repository := "mesh-catalog"
 	if module == BuilderModule {
-		repository = "mesh-controller"
+		t.Skipf("NOT JUDGED: genesis still installs build-agent, which left mesh-controller with R4g (ADR 0524 section 5); " +
+			"a new mesh cannot raise a builder until issue 1152 gives genesis one, and this test is judged again with it")
 	}
+	repository := "mesh-catalog"
 	inside := filepath.Join(repository, "modules", module, "module.json")
 	if root := os.Getenv("MESH_CHECK_BESIDE"); root != "" {
 		raw, err := os.ReadFile(filepath.Join(root, inside))
diff --git a/internal/bootstrap/genesis_form_test.go b/internal/bootstrap/genesis_form_test.go
index b22da3a..3aceee0 100644
--- a/internal/bootstrap/genesis_form_test.go
+++ b/internal/bootstrap/genesis_form_test.go
@@ -241,9 +241,18 @@ func TestAFileNothingOfTheControllerWritesIsStillRefused(t *testing.T) {
 // The controller's own manifest, as the mesh runs it, passes step 9 (issue 597): in a merge check the
 // node-engine's check has the controller cloned beside it (MESH_CHECK_BESIDE), where it must be; else a
 // checkout beside this one; else it skips aloud.
+//
+// **The checker running today places no controller beside this repository** (issue 1295, R4g): its rules put only the
+// catalogue and mesh-sdk beside mesh-host, and until R4g deleted this repository's merge-check.sh nothing here was judged
+// by it. A MESH_CHECK_BESIDE without a mesh-controller directory therefore skips aloud; mesh-delivery #27 places the
+// controller from R4g's delivery on, and this is a failure again then. A directory without its module.json still fails.
 func TestTheControllersOwnManifestPassesStepNine(t *testing.T) {
 	var manifest []byte
 	if root := os.Getenv("MESH_CHECK_BESIDE"); root != "" {
+		if info, err := os.Stat(filepath.Join(root, "mesh-controller")); err != nil || !info.IsDir() {
+			t.Skip("NOT JUDGED: the checker running today places no mesh-controller beside mesh-host's check; " +
+				"mesh-delivery #27 places it from R4g's delivery on, and this is a failure again then (issue 1295)")
+		}
 		raw, err := os.ReadFile(filepath.Join(root, "mesh-controller", "module.json"))
 		if err != nil {
 			t.Fatalf("the controller is not beside this check in MESH_CHECK_BESIDE=%s: %v", root, err)
diff --git a/internal/bootstrap/genesis_toolchains_test.go b/internal/bootstrap/genesis_toolchains_test.go
index 8523054..cfae225 100644
--- a/internal/bootstrap/genesis_toolchains_test.go
+++ b/internal/bootstrap/genesis_toolchains_test.go
@@ -26,6 +26,11 @@ func TestTheBaseStepBuildsEveryToolchainAGenesisModuleIsCompiledIn(t *testing.T)
 		built[tc.Language] = true
 	}
 	for _, module := range genesisModules {
+		if module == BuilderModule {
+			t.Logf("NOT JUDGED: genesis still installs build-agent, which left mesh-controller with R4g (ADR 0524 section 5); " +
+				"only build-agent is set aside here until issue 1152 gives genesis a builder, the other modules are judged")
+			continue
+		}
 		var m struct {
 			Build struct {
 				Artifacts []struct {
diff --git a/merge-check.sh b/merge-check.sh
deleted file mode 100755
index 14c2060..0000000
--- a/merge-check.sh
+++ /dev/null
@@ -1,59 +0,0 @@
-#!/bin/sh
-# mesh-check-toolchain: go
-#
-# The node-engine's own check (novox/hq ADR 0237 as amended): the second layer of a pull request's merge
-# check, `mesh/repo-check`, run by the build seat in the mesh's Go toolchain — and by hand.
-#
-# The gate — the controller the mesh runs, built with THIS change's validator in place of the one it
-# vendors, composing and validating every machine of the facts snapshot — is the build seat's first layer
-# (`mesh/merge-gate`), run because the mesh's module graph builds `mesh-host` from this repository and
-# judged so because it does. It is not repeated here. This is the code's own quality and its suite:
-# formatted, vetted, and every test, under the race detector when the toolchain has a C compiler.
-#
-# Exit 0 is a pass; anything else fails `mesh/repo-check` with the last line printed.
-set -eu
-
-unformatted=$(gofmt -l .)
-if [ -n "$unformatted" ]; then
-	echo "not gofmt'd:"
-	echo "$unformatted"
-	exit 1
-fi
-CGO_ENABLED=0 go vet ./...
-
-# **The tests that need a real bus** (MESH_TEST_NATS) run against a throwaway nats-server with JetStream when
-# the toolchain holds one, so the link the node-engine dials is tested as it is used (hq issue 331: every
-# unit test used fake links, and the real one could not ask a tool). Said when it cannot: a skipped test
-# is not a passed one. A caller that sets MESH_TEST_NATS keeps its own bus.
-if [ -z "${MESH_TEST_NATS:-}" ]; then
-	if command -v nats-server >/dev/null 2>&1; then
-		bus_dir=$(mktemp -d)
-		bus_port=$((20000 + $$ % 20000))
-		nats-server -js -a 127.0.0.1 -p "$bus_port" -sd "$bus_dir" >"$bus_dir/log" 2>&1 &
-		bus_pid=$!
-		trap 'kill "$bus_pid" 2>/dev/null || true; rm -rf "$bus_dir"' EXIT
-		up=0
-		for _ in 1 2 3 4 5 6 7 8 9 10; do
-			if grep -q "Server is ready" "$bus_dir/log"; then
-				up=1
-				break
-			fi
-			sleep 0.5
-		done
-		if [ "$up" -ne 1 ]; then
-			echo "the throwaway nats-server did not start:"
-			cat "$bus_dir/log"
-			exit 1
-		fi
-		export MESH_TEST_NATS="nats://127.0.0.1:$bus_port"
-	else
-		echo "NOT RUN AGAINST A BUS: the toolchain holds no nats-server; the tests that need one are skipped"
-	fi
-fi
-
-if command -v gcc >/dev/null 2>&1; then
-	CGO_ENABLED=1 go test -tags integration -race -count=1 ./...
-else
-	echo "NOT RACE-CHECKED: the toolchain holds no C compiler; the suite runs without the race detector"
-	CGO_ENABLED=0 go test -tags integration -count=1 ./...
-fi