NVIDIA
diff --git a/‎src/lib/actions/sandbox/rebuild-flow-lifecycle.test.ts‎
Lines changed: 4 additions & 1 deletion b/‎src/lib/actions/sandbox/rebuild-flow-lifecycle.test.ts‎
Lines changed: 4 additions & 1 deletion
diff --git a/‎src/lib/actions/sandbox/snapshot/backup-authority-script.test.ts‎
Lines changed: 179 additions & 0 deletions b/‎src/lib/actions/sandbox/snapshot/backup-authority-script.test.ts‎
Lines changed: 179 additions & 0 deletions
@@ -84,7 +84,10 @@ describe("rebuildSandbox flow: lifecycle", () => {
     ).resolves.toBeUndefined();
 
     expect(harness.backupSandboxStateSpy).toHaveBeenCalledOnce();
-    expect(harness.backupSandboxStateSpy).toHaveBeenCalledWith("alpha");
+    expect(harness.backupSandboxStateSpy).toHaveBeenCalledWith(
+      "alpha",
+      expect.objectContaining({ captureStateFile: expect.any(Function) }),
+    );
     expect(harness.prepareMcpBridgesForRebuildSpy).toHaveBeenCalledWith("alpha");
     expect(harness.prepareMcpBridgesForRebuildSpy.mock.invocationCallOrder[0]).toBeLessThan(
       harness.warnUnpreservedUserManagedFilesSpy.mock.invocationCallOrder[0],
 
@@ -0,0 +1,179 @@
+// SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+import { spawnSync } from "node:child_process";
+
+import { afterEach, describe, expect, it } from "vitest";
+
+import { OPENCLAW_CONFIG_CAPTURE_SCRIPT } from "./backup-authority";
+
+const CONFIG_NAME = "openclaw.json";
+const MAX_CONFIG_BYTES = 16 * 1024 * 1024;
+const PROTOCOL_PREFIX = "nemoclaw-openclaw-config-capture:";
+const fixtureRoots: string[] = [];
+
+interface CaptureResult {
+  readonly status: number | null;
+  readonly stdout: Buffer;
+  readonly stderr: string;
+}
+
+function fixtureDirectory(): string {
+  const root = fs.mkdtempSync(path.join(os.tmpdir(), "nemoclaw-openclaw-capture-"));
+  fixtureRoots.push(root);
+  const directory = path.join(root, ".openclaw");
+  fs.mkdirSync(directory);
+  return directory;
+}
+
+function runCapture(directory: string, script = OPENCLAW_CONFIG_CAPTURE_SCRIPT): CaptureResult {
+  const result = spawnSync("/usr/bin/python3", ["-I", "-S", "-c", script, directory, CONFIG_NAME], {
+    encoding: null,
+    timeout: 30_000,
+    maxBuffer: MAX_CONFIG_BYTES + 1024 * 1024,
+  });
+  return {
+    status: result.status,
+    stdout: Buffer.isBuffer(result.stdout) ? result.stdout : Buffer.alloc(0),
+    stderr: Buffer.isBuffer(result.stderr) ? result.stderr.toString("utf8") : "",
+  };
+}
+
+function mutationHarness(mutation: string): string {
+  return `import os, sys
+capture_script = ${JSON.stringify(OPENCLAW_CONFIG_CAPTURE_SCRIPT)}
+directory = sys.argv[1]
+name = sys.argv[2]
+real_read = os.read
+mutated = False
+def mutate_after_first_read(fd, size):
+    global mutated
+    data = real_read(fd, size)
+    if not mutated:
+        mutated = True
+${mutation}
+    return data
+os.read = mutate_after_first_read
+exec(capture_script)
+`;
+}
+
+afterEach(() => {
+  for (const root of fixtureRoots.splice(0)) {
+    fs.rmSync(root, { recursive: true, force: true });
+  }
+});
+
+describe("OpenClaw privileged config capture script", () => {
+  it("returns bytes only for a stable regular file", () => {
+    const directory = fixtureDirectory();
+    const expected = Buffer.from('{"models":{"default":"nvidia/test"}}\n');
+    fs.writeFileSync(path.join(directory, CONFIG_NAME), expected);
+
+    const result = runCapture(directory);
+
+    expect(result).toEqual({ status: 0, stdout: expected, stderr: "" });
+  });
+
+  it("returns all bytes for a stable file at the 16 MiB limit", () => {
+    const directory = fixtureDirectory();
+    const expected = Buffer.alloc(MAX_CONFIG_BYTES, 0xa5);
+    fs.writeFileSync(path.join(directory, CONFIG_NAME), expected);
+
+    const result = runCapture(directory);
+
+    expect(result.status).toBe(0);
+    expect(result.stderr).toBe("");
+    expect(result.stdout).toHaveLength(expected.length);
+    expect(result.stdout.equals(expected)).toBe(true);
+  });
+
+  it.each([
+    {
+      kind: "symbolic link",
+      setup(directory: string) {
+        const target = path.join(path.dirname(directory), "target.json");
+        fs.writeFileSync(target, "target");
+        fs.symlinkSync(target, path.join(directory, CONFIG_NAME));
+      },
+    },
+    {
+      kind: "hard link",
+      setup(directory: string) {
+        const target = path.join(path.dirname(directory), "target.json");
+        fs.writeFileSync(target, "target");
+        fs.linkSync(target, path.join(directory, CONFIG_NAME));
+      },
+    },
+    {
+      kind: "FIFO",
+      setup(directory: string) {
+        const result = spawnSync("mkfifo", [path.join(directory, CONFIG_NAME)]);
+        expect(result.status).toBe(0);
+      },
+    },
+    {
+      kind: "directory",
+      setup(directory: string) {
+        fs.mkdirSync(path.join(directory, CONFIG_NAME));
+      },
+    },
+    {
+      kind: "oversized file",
+      setup(directory: string) {
+        const descriptor = fs.openSync(path.join(directory, CONFIG_NAME), "w");
+        try {
+          fs.ftruncateSync(descriptor, MAX_CONFIG_BYTES + 1);
+        } finally {
+          fs.closeSync(descriptor);
+        }
+      },
+    },
+  ])("rejects a $kind without returning captured bytes", ({ setup }) => {
+    const directory = fixtureDirectory();
+    setup(directory);
+
+    const result = runCapture(directory);
+
+    expect(result.status).not.toBe(0);
+    expect(result.stdout).toEqual(Buffer.alloc(0));
+    expect(result.stderr).toContain(PROTOCOL_PREFIX);
+  });
+
+  it("rejects a file replaced during the read without returning captured bytes", () => {
+    const directory = fixtureDirectory();
+    fs.writeFileSync(path.join(directory, CONFIG_NAME), "original");
+    const script = mutationHarness(
+      `        original = os.path.join(directory, name)\n` +
+        `        os.rename(original, original + ".old")\n` +
+        `        with open(original, "wb") as replacement:\n` +
+        `            replacement.write(b"replacement")`,
+    );
+
+    const result = runCapture(directory, script);
+
+    expect(result.status).toBe(13);
+    expect(result.stdout).toEqual(Buffer.alloc(0));
+    expect(result.stderr).toBe(`${PROTOCOL_PREFIX}file-changed-during-read\n`);
+  });
+
+  it("rejects a directory replaced during the read without returning captured bytes", () => {
+    const directory = fixtureDirectory();
+    fs.writeFileSync(path.join(directory, CONFIG_NAME), "original");
+    const script = mutationHarness(
+      `        os.rename(directory, directory + ".old")\n` +
+        `        os.mkdir(directory)\n` +
+        `        with open(os.path.join(directory, name), "wb") as replacement:\n` +
+        `            replacement.write(b"replacement")`,
+    );
+
+    const result = runCapture(directory, script);
+
+    expect(result.status).toBe(13);
+    expect(result.stdout).toEqual(Buffer.alloc(0));
+    expect(result.stderr).toBe(`${PROTOCOL_PREFIX}directory-changed-during-read\n`);
+  });
+});