diff --git a/.github/workflows/hygiene.yml b/.github/workflows/hygiene.yml
index 9beba92..f9b7d73 100644
--- a/.github/workflows/hygiene.yml
+++ b/.github/workflows/hygiene.yml
@@ -23,6 +23,8 @@ on:
       - 'scripts/verify-action-pins.py'
       - 'scripts/verify-tag-currency.sh'
       - 'scripts/verify-trait-copies.py'
+      - 'scripts/verify-credential-guard-copies.py'
+      - 'src/Testing/CredentialLiterals.php'
       - 'scripts/verify-vcs-urls.py'
 
 concurrency:
@@ -96,6 +98,16 @@ jobs:
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
+      # The same shape for the credential guard: a repository that cannot depend on
+      # package-tools carries a local port of CredentialLiterals, which must declare why and
+      # which RULES_VERSION it mirrors. notifications' copy fell two releases behind before
+      # this existed. simtabi is read too, for sis-sdk and lacommerce; GITHUB_TOKEN sees only
+      # public repositories there, so a private copy is checked by a local --from-checkout run.
+      - name: Every credential-guard copy declares a reason and mirrors the current rules
+        run: python3 scripts/verify-credential-guard-copies.py --org laranail --org simtabi
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
   vcs-urls:
     name: VCS urls
     runs-on: ubuntu-latest
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 58c9fa1..f38e6b2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,18 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- `CredentialLiterals::RULES_VERSION` (`0.1.10`), the release in which the scanner's rules last
+  changed. `CredentialLiteralsRulesVersionTest` pins a fingerprint of the scanner's source, so a
+  rule cannot change without the version moving.
+- `scripts/verify-credential-guard-copies.py`, run by the scheduled hygiene job over laranail and
+  simtabi. Every local port of the scanner must declare
+  `@credential-guard-copy reason=… mirrors=…`. The script fails a copy that is undeclared, whose
+  reason (`php-floor-below-package-tools` or `outside-laranail`) no longer holds, or that mirrors
+  older rules than `RULES_VERSION`. notifications' copy had fallen behind 0.1.10 unnoticed before
+  this existed.
+
 ## [0.1.11] - 2026-10-19
 
 ### Fixed
diff --git a/docs/tools/test-credentials.md b/docs/tools/test-credentials.md
index c0298d7..a040f0d 100644
--- a/docs/tools/test-credentials.md
+++ b/docs/tools/test-credentials.md
@@ -140,6 +140,48 @@ Prefer a name that is not a credential's where the test allows it (`RFC7677_SALT
 `ADMIN_PASSWORD`). `exemptFiles` skips a whole file by basename. Use it sparingly: a file-wide
 skip also covers literals added to that file later.
 
+## Local copies
+
+A repository that cannot depend on package-tools carries a port of the scanner in its own
+`NoLiteralCredentialsTest.php`:
+- **notifications and enumerator** support PHP 8.3, below package-tools' floor.
+- **simtabi/sis-sdk and simtabi/lacommerce** stay independent of the laranail family.
+
+A copy declares itself in its docblock:
+
+```php
+/**
+ * @credential-guard-copy reason=php-floor-below-package-tools mirrors=0.1.10
+ */
+```
+
+`reason` is one of two slugs, each a fact about the repository's `composer.json`:
+
+| Slug | Holds when |
+|---|---|
+| `php-floor-below-package-tools` | `require.php` admits a version below package-tools' floor |
+| `outside-laranail` | the package name is not `laranail/*` |
+
+`mirrors` must equal `CredentialLiterals::RULES_VERSION`, the release in which the rules last
+changed. `scripts/verify-credential-guard-copies.py` checks every repository in the scheduled
+hygiene job. It fails a copy that is undeclared, behind, or whose reason no longer holds;
+when a reason stops holding, switch that repository to the shared guard.
+
+`CredentialLiteralsRulesVersionTest` pins a fingerprint of the scanner's source, so changing a
+rule without bumping `RULES_VERSION` fails package-tools' own suite.
+
+When you change a rule:
+1. Bump `RULES_VERSION` to the release you are cutting.
+2. Update both pins in that test.
+3. Port the change into each copy, and update its `mirrors=`.
+
+The hygiene job's token reads only public repositories, so a private copy (sis-sdk) is checked
+by running the script locally:
+
+```bash
+python3 scripts/verify-credential-guard-copies.py --from-checkout ../ --from-checkout ../../../simtabi/packages
+```
+
 ## Limits
 
 The guard reads PHP source only. Credentials in `phpunit.xml`, `.env.testing` or a workflow file
diff --git a/scripts/verify-credential-guard-copies.py b/scripts/verify-credential-guard-copies.py
new file mode 100644
index 0000000..30178fa
--- /dev/null
+++ b/scripts/verify-credential-guard-copies.py
@@ -0,0 +1,179 @@
+#!/usr/bin/env python3
+#
+# Every repository that cannot depend on laranail/package-tools carries a local copy
+# of its credential guard (`src/Testing/CredentialLiterals.php` and
+# `AssertsNoLiteralCredentials`), in a test named NoLiteralCredentialsTest.php. A copy
+# is a port, not a byte-for-byte duplicate, so nothing compares it with the original,
+# and it falls behind silently: on 2026-10-20 laranail/notifications' copy still had
+# the pre-0.1.10 rules, with no purpose check and none of the false-positive
+# exclusions, while three other copies had been ported at 0.1.10.
+#
+# So a copy declares itself, and this script checks three things:
+#
+#   1. A COPY MUST DECLARE ITSELF, machine-readably, in its docblock:
+#
+#          @credential-guard-copy reason=<slug> mirrors=<version>
+#
+#      A NoLiteralCredentialsTest.php that imports package-tools'
+#      AssertsNoLiteralCredentials is the shared guard and needs nothing. Anything else
+#      is a copy. A copy with no declaration is an ERROR.
+#
+#   2. THE REASON MUST BE ONE A MACHINE CAN FALSIFY, against the repo's composer.json:
+#
+#          php-floor-below-package-tools  -- `require.php` admits a version below
+#                                            package-tools' own floor
+#          outside-laranail               -- the package is not laranail/*: it stays
+#                                            independent of the family
+#
+#      An unknown slug is an error, and a reason that no longer holds is an error: the
+#      repo can then take the shared guard, and should.
+#
+#   3. THE COPY MUST MIRROR THE CURRENT RULES. `mirrors=` must equal
+#      CredentialLiterals::RULES_VERSION, which package-tools bumps whenever it changes a
+#      rule. Its fingerprint test, CredentialLiteralsRulesVersionTest, makes that bump
+#      impossible to forget.
+#
+# A run that inspects nothing fails: a source that cannot be read must not pass as
+# "no copies found".
+#
+# Usage:
+#   verify-credential-guard-copies.py --org laranail --org simtabi        (CI, API)
+#   verify-credential-guard-copies.py --from-checkout DIR [--from-checkout DIR ...]
+
+from __future__ import annotations
+
+import argparse
+import importlib.util
+import json
+import re
+import sys
+from pathlib import Path
+
+HERE = Path(__file__).resolve().parent
+
+# The transport and the two sources are the trait-copy script's: one implementation of
+# reading the org, not two that can drift into checking different things.
+_spec = importlib.util.spec_from_file_location("trait_copies", HERE / "verify-trait-copies.py")
+_tc = importlib.util.module_from_spec(_spec)
+assert _spec.loader is not None
+_spec.loader.exec_module(_tc)
+
+Remote, Checkout, NotFound, Unreachable, php_floor = (
+    _tc.Remote, _tc.Checkout, _tc.NotFound, _tc.Unreachable, _tc.php_floor,
+)
+
+KNOWN_REASONS = ("php-floor-below-package-tools", "outside-laranail")
+GUARD = re.compile(r"(^|/)tests/.*NoLiteralCredentialsTest\.php$")
+SHARED = re.compile(r"use\s+Simtabi\\Laranail\\Package\\Tools\\Testing\\AssertsNoLiteralCredentials\s*;")
+DECLARATION = re.compile(r"@credential-guard-copy\s+reason=([\w-]+)\s+mirrors=([\d.]+)")
+RULES_VERSION = re.compile(r"RULES_VERSION\s*=\s*'([\d.]+)'")
+
+
+def rules_version() -> str:
+    source = (HERE.parent / "src/Testing/CredentialLiterals.php").read_text(encoding="utf-8")
+    m = RULES_VERSION.search(source)
+    if not m:
+        sys.exit("CredentialLiterals::RULES_VERSION not found; cannot check copies.")
+    return m.group(1)
+
+
+def own_floor() -> tuple[int, ...]:
+    floor = php_floor((HERE.parent / "composer.json").read_text(encoding="utf-8"))
+    if floor is None:
+        sys.exit("package-tools' own require.php could not be parsed.")
+    return floor
+
+
+def check_reason(slug: str, manifest: str | None, floor: tuple[int, ...]) -> str | None:
+    """None when the reason holds; otherwise why it does not."""
+    if slug == "php-floor-below-package-tools":
+        mine = php_floor(manifest)
+        if mine is None:
+            return "no parseable `require.php`, so the floor cannot be compared"
+        if mine >= floor:
+            return (f"floor {'.'.join(map(str, mine))} is not below package-tools' "
+                    f"{'.'.join(map(str, floor))}: use the shared guard instead")
+        return None
+
+    if slug == "outside-laranail":
+        try:
+            name = json.loads(manifest or "{}").get("name", "")
+        except json.JSONDecodeError:
+            return "composer.json is not valid JSON, so the package name cannot be read"
+        if name.startswith("laranail/"):
+            return f"the package is {name}, inside the family: use the shared guard instead"
+        return None
+
+    return f"unrecognised reason -- must be one of {', '.join(KNOWN_REASONS)}"
+
+
+def check(sources: list, version: str, floor: tuple[int, ...]) -> int:
+    inspected = shared = copies = 0
+    unreadable: list[str] = []
+    errors: list[str] = []
+
+    for source in sources:
+        label = getattr(source, "org", None) or str(getattr(source, "root", "?"))
+        for pkg in source.packages():
+            try:
+                guards = [p for p in source.paths(pkg) if GUARD.search(p)]
+            except Unreachable as e:
+                unreadable.append(f"{label}/{pkg}: {e}")
+                continue
+            inspected += 1
+
+            for path in guards:
+                body = source.read(pkg, path) or ""
+                where = f"{label}/{pkg}/{path}"
+                declared = DECLARATION.search(body)
+
+                if SHARED.search(body):
+                    shared += 1
+                    if declared:
+                        errors.append(f"{where}: uses the shared guard but still declares a copy")
+                    continue
+
+                copies += 1
+                if not declared:
+                    errors.append(f"{where}: a local copy with no `@credential-guard-copy reason=… mirrors=…`")
+                    continue
+
+                slug, mirrors = declared.groups()
+                problem = check_reason(slug, source.read(pkg, "composer.json"), floor)
+                if problem:
+                    errors.append(f"{where}: reason={slug}: {problem}")
+                if mirrors != version:
+                    errors.append(f"{where}: mirrors {mirrors}, but the rules are at {version}; port the changes")
+                if not errors or not errors[-1].startswith(where):
+                    print(f"  ok    {where} (reason={slug}, mirrors={mirrors})")
+
+    print(f"\nInspected {inspected} repositories: {shared} shared guard(s), {copies} local cop(ies).")
+    for u in unreadable:
+        print(f"  unreadable  {u}")
+    if inspected == 0:
+        print("Nothing was inspected, so this proved nothing.")
+        return 1
+    for e in errors:
+        print(f"  ERROR {e}")
+    return 1 if errors else 0
+
+
+def main() -> int:
+    ap = argparse.ArgumentParser(description=__doc__)
+    ap.add_argument("--org", action="append", default=[])
+    ap.add_argument("--from-checkout", metavar="DIR", action="append", default=[])
+    args = ap.parse_args()
+
+    sources = [Checkout(Path(d)) for d in args.from_checkout] + [Remote(o) for o in args.org]
+    if not sources:
+        sources = [Remote("laranail")]
+
+    try:
+        return check(sources, rules_version(), own_floor())
+    except Unreachable as e:
+        print(f"Could not read the org: {e}")
+        return 1
+
+
+if __name__ == "__main__":
+    sys.exit(main())
diff --git a/src/Testing/CredentialLiterals.php b/src/Testing/CredentialLiterals.php
index aa44fe2..387359b 100644
--- a/src/Testing/CredentialLiterals.php
+++ b/src/Testing/CredentialLiterals.php
@@ -22,6 +22,15 @@ final class CredentialLiterals
      */
     public const string EXEMPTION = '@credential-literal-exempt';
 
+    /**
+     * The package-tools release in which these rules last changed. A repository that cannot
+     * depend on package-tools ports them into a local copy, which declares the version it
+     * mirrors (`@credential-guard-copy reason=… mirrors=…`); scripts/verify-credential-guard-copies.py
+     * fails any copy behind this. Changing a rule without bumping this fails
+     * CredentialLiteralsRulesVersionTest, so the copies cannot be left behind silently.
+     */
+    public const string RULES_VERSION = '0.1.10';
+
     /**
      * Every literal credential in $source, as [byte offset, rule, literal].
      *
diff --git a/tests/Feature/CredentialLiteralsRulesVersionTest.php b/tests/Feature/CredentialLiteralsRulesVersionTest.php
new file mode 100644
index 0000000..0e8ab88
--- /dev/null
+++ b/tests/Feature/CredentialLiteralsRulesVersionTest.php
@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+use Simtabi\Laranail\Package\Tools\Testing\CredentialLiterals;
+
+/*
+ * The scanner's rules are ported into local copies by repositories that cannot depend on
+ * package-tools (notifications, enumerator, simtabi/sis-sdk, simtabi/lacommerce). Each copy
+ * declares the RULES_VERSION it mirrors, and scripts/verify-credential-guard-copies.py fails a
+ * copy that is behind. That only works if RULES_VERSION moves when a rule does, so this pins
+ * the source the version describes.
+ *
+ * If this fails:
+ *  - you changed a rule: set RULES_VERSION to the release you are cutting, update both pins
+ *    below, and port the change into every local copy;
+ *  - you changed nothing a copy needs (a comment, formatting): update the fingerprint only.
+ */
+it('moves RULES_VERSION whenever the scanner source changes', function (): void {
+    $source = (string) file_get_contents(dirname(__DIR__, 2) . '/src/Testing/CredentialLiterals.php');
+    $fingerprint = hash('sha256', (string) preg_replace('/^.*RULES_VERSION = .*\n/m', '', $source));
+
+    expect(CredentialLiterals::RULES_VERSION)->toBe('0.1.10')
+        ->and($fingerprint)->toBe('eeabe337494d7e05cd53b29388bafc096dc145d33f579dd9bf10aa579f960658');
+});
diff --git a/tests/Feature/VerifyCredentialGuardCopiesScriptTest.php b/tests/Feature/VerifyCredentialGuardCopiesScriptTest.php
new file mode 100644
index 0000000..cca1219
--- /dev/null
+++ b/tests/Feature/VerifyCredentialGuardCopiesScriptTest.php
@@ -0,0 +1,77 @@
+<?php
+
+declare(strict_types=1);
+
+use Symfony\Component\Process\Process;
+use Simtabi\Laranail\Package\Tools\Testing\CredentialLiterals;
+
+/*
+ * scripts/verify-credential-guard-copies.py against a throwaway `packages/` tree, so its rules
+ * are pinned without the network: a shared guard passes, a declared copy whose reason holds and
+ * whose mirrored version is current passes, and an undeclared copy, a stale copy or a reason that
+ * no longer holds each fail.
+ */
+function guardCopiesTree(array $repos): string
+{
+    $root = sys_get_temp_dir() . '/guard-copies-' . bin2hex(random_bytes(5));
+
+    foreach ($repos as $name => [$composer, $guard]) {
+        @mkdir("{$root}/{$name}/.git", 0777, true);
+        @mkdir("{$root}/{$name}/tests/Architecture", 0777, true);
+        file_put_contents("{$root}/{$name}/composer.json", json_encode($composer));
+        file_put_contents("{$root}/{$name}/tests/Architecture/NoLiteralCredentialsTest.php", $guard);
+    }
+
+    return $root;
+}
+
+function runGuardCopies(array $repos): Process
+{
+    $process = new Process(['python3', dirname(__DIR__, 2) . '/scripts/verify-credential-guard-copies.py', '--from-checkout', guardCopiesTree($repos)]);
+    $process->run();
+
+    return $process;
+}
+
+function copyDeclaring(string $reason, string $mirrors): string
+{
+    return "<?php\n/**\n * @credential-guard-copy reason={$reason} mirrors={$mirrors}\n */\n";
+}
+
+it('passes the shared guard and a current, justified copy', function (): void {
+    $process = runGuardCopies([
+        'shared'   => [['name' => 'laranail/shared', 'require' => ['php' => '^8.4.1']], "<?php\nuse Simtabi\\Laranail\\Package\\Tools\\Testing\\AssertsNoLiteralCredentials;\n"],
+        'old-php'  => [['name' => 'laranail/old-php', 'require' => ['php' => '^8.3']], copyDeclaring('php-floor-below-package-tools', CredentialLiterals::RULES_VERSION)],
+        'outsider' => [['name' => 'simtabi/outsider', 'require' => ['php' => '^8.5']], copyDeclaring('outside-laranail', CredentialLiterals::RULES_VERSION)],
+    ]);
+
+    expect($process->getExitCode())->toBe(0, $process->getOutput())
+        ->and($process->getOutput())->toContain('Inspected 3 repositories: 1 shared guard(s), 2 local cop(ies).');
+});
+
+it('fails an undeclared copy, a stale copy and a reason that no longer holds', function (): void {
+    $process = runGuardCopies([
+        'undeclared' => [['name' => 'laranail/undeclared', 'require' => ['php' => '^8.3']], "<?php\n// a hand-rolled scanner\n"],
+        'stale'      => [['name' => 'laranail/stale', 'require' => ['php' => '^8.3']], copyDeclaring('php-floor-below-package-tools', '0.1.0')],
+        'expired'    => [['name' => 'laranail/expired', 'require' => ['php' => '^8.4.1 || ^8.5']], copyDeclaring('php-floor-below-package-tools', CredentialLiterals::RULES_VERSION)],
+        'insider'    => [['name' => 'laranail/insider', 'require' => ['php' => '^8.5']], copyDeclaring('outside-laranail', CredentialLiterals::RULES_VERSION)],
+    ]);
+
+    expect($process->getExitCode())->toBe(1)
+        ->and($process->getOutput())
+        ->toContain('undeclared/tests/Architecture/NoLiteralCredentialsTest.php: a local copy with no')
+        ->toContain('stale/tests/Architecture/NoLiteralCredentialsTest.php: mirrors 0.1.0')
+        ->toContain('expired/tests/Architecture/NoLiteralCredentialsTest.php: reason=php-floor-below-package-tools: floor 8.4.1 is not below')
+        ->toContain('insider/tests/Architecture/NoLiteralCredentialsTest.php: reason=outside-laranail: the package is laranail/insider');
+});
+
+it('refuses to pass when it inspected nothing', function (): void {
+    $root = sys_get_temp_dir() . '/guard-copies-empty-' . bin2hex(random_bytes(5));
+    mkdir($root);
+
+    $process = new Process(['python3', dirname(__DIR__, 2) . '/scripts/verify-credential-guard-copies.py', '--from-checkout', $root]);
+    $process->run();
+
+    expect($process->getExitCode())->toBe(1)
+        ->and($process->getOutput())->toContain('Nothing was inspected');
+});