diff --git a/craft/scripts/fake-date-preload.cjs b/craft/scripts/fake-date-preload.cjs
new file mode 100644
index 0000000..2cb97fa
--- /dev/null
+++ b/craft/scripts/fake-date-preload.cjs
@@ -0,0 +1,9 @@
+// Test helper: freeze the wall clock for a child process. FAKE_NOW=<ISO date> (node -r this).
+const RealDate = Date;
+const fixed = new RealDate(process.env.FAKE_NOW).getTime();
+if (!Number.isFinite(fixed)) throw new Error('FAKE_NOW must be a valid ISO date');
+class FakeDate extends RealDate {
+  constructor(...a) { if (a.length === 0) super(fixed); else super(...a); }
+  static now() { return fixed; }
+}
+globalThis.Date = FakeDate;
diff --git a/craft/scripts/gen-sitesmith-catalog.mjs b/craft/scripts/gen-sitesmith-catalog.mjs
index b2b90cb..b238da5 100644
--- a/craft/scripts/gen-sitesmith-catalog.mjs
+++ b/craft/scripts/gen-sitesmith-catalog.mjs
@@ -106,6 +106,14 @@ function extractProps(program, file, name) {
   return out;
 }
 
+/**
+ * Defaults computed from the wall clock when the editor module loads (Countdown.targetDate
+ * = today + 30 days). Emitting them would make the generated catalog (and the drift test)
+ * change every day and would teach the model a stale "default" date, so they are omitted
+ * from the catalog entirely.
+ */
+const VOLATILE_DEFAULTS = new Set(['Countdown.targetDate']);
+
 const COLOR_RE = /^(color|bg|bgValue|gradient)$|(colou?r|bg|background|gradientfrom|gradientto)$/i;
 const isTokenRef = (v) => typeof v === 'string' && /^var\(--wsb-[a-z-]+\)$/.test(v);
 
@@ -148,7 +156,7 @@ export async function buildCatalog() {
       if (COMMON_PROPS.has(p) || p === 'children') continue;
       const e = { ...info };
       delete e.optional;
-      if (p in defaults && !(typeof defaults[p] === 'string' && defaults[p].startsWith('data:'))) e.default = slimDefault(defaults[p]);
+      if (p in defaults && !VOLATILE_DEFAULTS.has(`${name}.${p}`) && !(typeof defaults[p] === 'string' && defaults[p].startsWith('data:'))) e.default = slimDefault(defaults[p]);
       if (info.type !== 'boolean' && info.type !== 'number' && COLOR_RE.test(p)) {
         e.color = true;
         if (isTokenRef(defaults[p])) e.tokenDefault = true;
diff --git a/craft/src/sitesmith/catalog.drift.test.ts b/craft/src/sitesmith/catalog.drift.test.ts
index b4dc4cf..073909b 100644
--- a/craft/src/sitesmith/catalog.drift.test.ts
+++ b/craft/src/sitesmith/catalog.drift.test.ts
@@ -26,8 +26,11 @@ const craftRoot: string = path.resolve(decodeURIComponent(new URL('.', import.me
 const committedPath: string = proc.env.SITESMITH_CATALOG_FILE
   ?? path.resolve(craftRoot, '../../whp/web-files/libs/sitesmith-catalog.generated.json');
 
-function regenerate(): string {
-  return execFileSync(proc.execPath, ['scripts/gen-sitesmith-catalog.mjs', '--stdout'], {
+function regenerate(fakeNow?: string): string {
+  const args = ['scripts/gen-sitesmith-catalog.mjs', '--stdout'];
+  if (fakeNow) args.unshift('-r', path.join(craftRoot, 'scripts/fake-date-preload.cjs'));
+  return execFileSync(proc.execPath, args, {
+    env: fakeNow ? { ...proc.env, FAKE_NOW: fakeNow } : proc.env,
     cwd: craftRoot, encoding: 'utf8', maxBuffer: 64 * 1024 * 1024, timeout: 120_000,
   });
 }
@@ -47,6 +50,14 @@ describe('sitesmith catalog', () => {
     expect(fresh).toBe(committed);
   }, 130_000);
 
+  test('catalog is date-independent (Countdown default date is volatile and must not leak in)', () => {
+    const a = regenerate('2026-12-01T12:00:00Z');
+    const b = regenerate('2027-03-09T12:00:00Z');
+    expect(a).toBe(b);
+    expect(JSON.parse(a).components.Countdown.props.targetDate.default).toBeUndefined();
+    expect(a).not.toMatch(/"\d{4}-\d{2}-\d{2}"/);
+  }, 130_000);
+
   test('catalog covers every resolver component, with derived facts', () => {
     const cat = JSON.parse(regenerate());
     const resolver = fs.readFileSync(path.join(craftRoot, 'src/components/resolver.ts'), 'utf8');