diff --git a/apps/mana/apps/web/src/lib/i18n/locales/cycles/parity.test.ts b/apps/mana/apps/web/src/lib/i18n/locales/cycles/parity.test.ts
new file mode 100644
index 000000000..bc133ac42
--- /dev/null
+++ b/apps/mana/apps/web/src/lib/i18n/locales/cycles/parity.test.ts
@@ -0,0 +1,72 @@
+/**
+ * i18n parity test for the cycles module.
+ *
+ * Ensures all 5 locale files (de/en/it/fr/es) have identical key
+ * structure — stub copies of en.json would otherwise drift silently
+ * as keys are added to de/en and forgotten in the others.
+ *
+ * The test does NOT enforce that values are different (stubs are
+ * allowed); it only enforces that the *shape* (nested key paths)
+ * matches exactly across all locales.
+ */
+
+import { describe, expect, it as test } from 'vitest';
+import de from './de.json';
+import en from './en.json';
+import itLocale from './it.json';
+import fr from './fr.json';
+import es from './es.json';
+
+type Dict = Record<string, unknown>;
+
+/** Flatten an object into dot-separated leaf key paths. */
+function flattenKeys(obj: Dict, prefix = ''): string[] {
+	const keys: string[] = [];
+	for (const [k, v] of Object.entries(obj)) {
+		const path = prefix ? `${prefix}.${k}` : k;
+		if (v && typeof v === 'object' && !Array.isArray(v)) {
+			keys.push(...flattenKeys(v as Dict, path));
+		} else {
+			keys.push(path);
+		}
+	}
+	return keys.sort();
+}
+
+const locales = {
+	de: de as Dict,
+	en: en as Dict,
+	it: itLocale as Dict,
+	fr: fr as Dict,
+	es: es as Dict,
+};
+
+describe('cycles i18n parity', () => {
+	const referenceKeys = flattenKeys(locales.de);
+
+	test('de has a non-empty set of keys', () => {
+		expect(referenceKeys.length).toBeGreaterThan(0);
+	});
+
+	for (const [lang, dict] of Object.entries(locales)) {
+		if (lang === 'de') continue;
+		test(`${lang} matches de key structure`, () => {
+			const langKeys = flattenKeys(dict);
+			expect(langKeys).toEqual(referenceKeys);
+		});
+	}
+
+	test('no locale has empty string values', () => {
+		for (const [lang, dict] of Object.entries(locales)) {
+			const flat = flattenKeys(dict);
+			for (const keyPath of flat) {
+				const value = keyPath.split('.').reduce<unknown>((acc, segment) => {
+					if (acc && typeof acc === 'object') return (acc as Dict)[segment];
+					return undefined;
+				}, dict);
+				expect(value, `${lang}.${keyPath}`).not.toBe('');
+				expect(typeof value, `${lang}.${keyPath}`).toBe('string');
+			}
+		}
+	});
+});