diff --git a/package.json b/package.json
index d5662fa4..0f6957f2 100644
--- a/package.json
+++ b/package.json
@@ -48,7 +48,7 @@
     "lint:oxlint": "oxlint --type-aware --tsconfig ./tsconfig.oxlint.json ./src ./convex ./packages/clawhub/src ./packages/clawhub-admin/src ./packages/schema/src",
     "llms:check": "bun scripts/generate-llms-txt.ts --check",
     "llms:generate": "bun scripts/generate-llms-txt.ts",
-    "preinstall": "bunx only-allow bun",
+    "preinstall": "bunx --bun only-allow@1.2.2 bun",
     "preview": "bun --bun vite preview",
     "proof:publish": "node scripts/ui-proof-publish.mjs",
     "proof:ui": "node scripts/ui-proof.mjs",
diff --git a/scripts/package-config.test.ts b/scripts/package-config.test.ts
new file mode 100644
index 00000000..7cb09259
--- /dev/null
+++ b/scripts/package-config.test.ts
@@ -0,0 +1,24 @@
+/* @vitest-environment node */
+
+import { readFileSync } from "node:fs";
+import { join } from "node:path";
+import { describe, expect, it } from "vitest";
+
+const repoRoot = process.cwd();
+const packageJson = JSON.parse(readFileSync(join(repoRoot, "package.json"), "utf8")) as {
+  scripts?: Record<string, string>;
+  devDependencies?: Record<string, string>;
+};
+const lockfile = readFileSync(join(repoRoot, "bun.lock"), "utf8");
+
+describe("package configuration", () => {
+  it("pins the preinstall package-manager guard to its declared version", () => {
+    const preinstall = packageJson.scripts?.preinstall ?? "";
+    const match = preinstall.match(/^bunx --bun only-allow@(\d+\.\d+\.\d+) bun$/);
+
+    const version = packageJson.devDependencies?.["only-allow"];
+
+    expect(match?.[1]).toBe(version);
+    expect(lockfile).toContain(`"only-allow": ["only-allow@${version}"`);
+  });
+});