diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index d83f74a7..04cd7b2d 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,5 +1,6 @@
 {
   ".": "18.66.1",
   "packages/brepjs-opencascade": "0.16.0",
+  "packages/brepjs-voxel-wasm": "0.1.0",
   "packages/brepjs-verify": "0.4.0"
 }
diff --git a/release-please-config.json b/release-please-config.json
index 90301ac5..3d5214e1 100644
--- a/release-please-config.json
+++ b/release-please-config.json
@@ -5,7 +5,12 @@
       "release-type": "node",
       "changelog-path": "CHANGELOG.md",
       "bump-minor-pre-major": true,
-      "exclude-paths": ["apps", "packages/brepjs-verify", "packages/brepjs-viewer"]
+      "exclude-paths": [
+        "apps",
+        "packages/brepjs-verify",
+        "packages/brepjs-viewer",
+        "packages/brepjs-voxel"
+      ]
     },
     "packages/brepjs-opencascade": {
       "release-type": "node",
@@ -13,6 +18,12 @@
       "component": "brepjs-opencascade",
       "bump-minor-pre-major": true
     },
+    "packages/brepjs-voxel-wasm": {
+      "release-type": "node",
+      "changelog-path": "CHANGELOG.md",
+      "component": "brepjs-voxel-wasm",
+      "bump-minor-pre-major": true
+    },
     "packages/brepjs-verify": {
       "release-type": "node",
       "changelog-path": "CHANGELOG.md",
diff --git a/scripts/check-layer-boundaries.sh b/scripts/check-layer-boundaries.sh
index 7121ce93..78fd2ccf 100755
--- a/scripts/check-layer-boundaries.sh
+++ b/scripts/check-layer-boundaries.sh
@@ -16,7 +16,9 @@ if [[ "${1:-}" == "--staged" ]]; then
   STAGED_ONLY=true
 fi
 
-SRC_DIR="src"
+# Scan root is overridable (default "src") so the enforcement itself can be
+# exercised against throwaway fixtures without touching the real tree.
+SRC_DIR="${BOUNDARY_SRC_DIR:-src}"
 ERRORS=()
 
 # Map directory to layer number
@@ -34,8 +36,8 @@ get_layer() {
 # Get top-level src directory from a file path
 get_src_dir() {
   local filepath="$1"
-  # Strip src/ prefix and get first directory component
-  local relative="${filepath#src/}"
+  # Strip the scan-root prefix and get first directory component
+  local relative="${filepath#"$SRC_DIR"/}"
   echo "${relative%%/*}"
 }
 
@@ -69,7 +71,7 @@ resolve_import_dir() {
     local combined="$source_dir/$import_path"
     # Normalize path
     resolved=$(python3 -c "import os.path; print(os.path.normpath('$combined'))" 2>/dev/null || echo "")
-    resolved="${resolved#src/}"
+    resolved="${resolved#"$SRC_DIR"/}"
   fi
 
   # Get the top-level directory
diff --git a/tests/layerBoundaries.test.ts b/tests/layerBoundaries.test.ts
new file mode 100644
index 00000000..20853434
--- /dev/null
+++ b/tests/layerBoundaries.test.ts
@@ -0,0 +1,82 @@
+/**
+ * Negative tests proving the layer-boundary script actually rejects upward
+ * imports (ADR-0013 §9 — "add negative tests proving enforcement is live").
+ *
+ * `scripts/check-layer-boundaries.sh` only emits a friendly "passed" line; a
+ * silent escape (e.g. a layer dir missing from `get_layer`, falling through to
+ * -1) would pass unnoticed. These tests run the real script against throwaway
+ * fixtures via the `BOUNDARY_SRC_DIR` override, so nothing touches `src/`, and
+ * assert it fails on forbidden imports and passes on allowed ones.
+ *
+ * Focus is the layers wired in for the voxel domain — voxel (L2) and lattice
+ * (L3) — but the harness covers the general rule.
+ */
+
+import { spawnSync } from 'node:child_process';
+import { mkdirSync, mkdtempSync, rmSync, writeFileSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { dirname, join, resolve } from 'node:path';
+import { fileURLToPath } from 'node:url';
+import { afterEach, describe, expect, it } from 'vitest';
+
+const repoRoot = resolve(dirname(fileURLToPath(import.meta.url)), '..');
+const script = join(repoRoot, 'scripts', 'check-layer-boundaries.sh');
+
+const tmpDirs: string[] = [];
+
+afterEach(() => {
+  for (const dir of tmpDirs.splice(0)) rmSync(dir, { recursive: true, force: true });
+});
+
+/**
+ * Write a single fixture `<layerDir>/fixture.ts` importing `importPath` into a
+ * throwaway scan root, run the boundary checker against it, and return the exit
+ * status (0 = passed, non-zero = violation reported).
+ */
+function checkImport(layerDir: string, importPath: string): { status: number; out: string } {
+  const root = mkdtempSync(join(tmpdir(), 'brepjs-boundary-'));
+  tmpDirs.push(root);
+  mkdirSync(join(root, layerDir), { recursive: true });
+  writeFileSync(join(root, layerDir, 'fixture.ts'), `import { thing } from '${importPath}';\n`);
+
+  const result = spawnSync('bash', [script], {
+    cwd: repoRoot,
+    env: { ...process.env, BOUNDARY_SRC_DIR: root },
+    encoding: 'utf8',
+  });
+  return { status: result.status ?? -1, out: `${result.stdout}${result.stderr}` };
+}
+
+describe('layer boundaries: forbidden upward imports are rejected', () => {
+  it('voxel (L2) → lattice (L3) is a violation', () => {
+    const { status, out } = checkImport('voxel', '@/lattice/index.js');
+    expect(status).not.toBe(0);
+    expect(out).toMatch(/VIOLATION/);
+  });
+
+  it('voxel (L2) → sketching (L3) is a violation', () => {
+    expect(checkImport('voxel', '@/sketching/index.js').status).not.toBe(0);
+  });
+
+  it('core (L1) → voxel (L2) is a violation (voxel sits above core)', () => {
+    expect(checkImport('core', '@/voxel/index.js').status).not.toBe(0);
+  });
+
+  it('kernel (L0) → lattice (L3) is a violation (lattice is top-layer)', () => {
+    expect(checkImport('kernel', '@/lattice/index.js').status).not.toBe(0);
+  });
+});
+
+describe('layer boundaries: allowed downward / same-layer imports pass', () => {
+  it('lattice (L3) → voxel (L2) is allowed', () => {
+    expect(checkImport('lattice', '@/voxel/index.js').status).toBe(0);
+  });
+
+  it('voxel (L2) → topology (L2) is allowed (same layer)', () => {
+    expect(checkImport('voxel', '@/topology/index.js').status).toBe(0);
+  });
+
+  it('voxel (L2) → core (L1) is allowed (downward)', () => {
+    expect(checkImport('voxel', '@/core/result.js').status).toBe(0);
+  });
+});