diff --git a/merge-check.sh b/merge-check.sh
index 6cd9316..4fc67c7 100755
--- a/merge-check.sh
+++ b/merge-check.sh
@@ -1,34 +1,29 @@
 #!/bin/sh
-# The merge check of the node-engine (novox/hq to-be 45 §9), run by the build seat on every pull request
-# before it merges, beside the controller the mesh runs and the facts snapshot the controller keeps.
+# mesh-check-toolchain: go
 #
-#   1. formatted, vetted, and the whole suite;
-#   2. the merge gate **with this change's validator**: the controller the mesh runs is built with the
-#      validator from this tree in place of the one it vendors, and every machine of the snapshot is
-#      composed and validated by it. A change to the node-engine that would refuse what the mesh sends
-#      today fails here, naming the machine — not on the first machine it reaches.
+# 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
-go vet ./...
-go test -count=1 ./...
+CGO_ENABLED=0 go vet ./...
 
-beside="${MESH_CHECK_BESIDE:?the controller the mesh runs is cloned beside this check}"
-judge_tree="$beside/mesh-controller"
-[ -f "$judge_tree/cmd/mesh-controller/merge_gate.go" ] || judge_tree="$beside/mesh-controller-main"
-vendored="$judge_tree/vendor/github.com/novox/mesh-host"
-for pkg in validate internal/declaration; do
-	rm -f "$vendored/$pkg"/*.go
-	for f in "$pkg"/*.go; do
-		case "$f" in *_test.go) ;; *) cp "$f" "$vendored/$pkg/" ;; esac
-	done
-done
-judge="$beside/bin/judge-with-this-validator"
-(cd "$judge_tree" && CGO_ENABLED=0 GOFLAGS=-mod=vendor GOPROXY=off go build -o "$judge" ./cmd/mesh-controller)
-"$judge" merge-gate --facts "$MESH_FACTS" --store "$MESH_GATE_POSTGRES" \
-	--repository "${MESH_CHECK_REPOSITORY:-novox/mesh-host}" --tree . \
-	--changed "${MESH_CHECK_CHANGED:-}" --json > "${MESH_CHECK_VERDICT:-/dev/null}"
+if command -v gcc >/dev/null 2>&1; then
+	CGO_ENABLED=1 go test -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 -count=1 ./...
+fi