diff --git a/tests/tavern-card-validator.test.js b/tests/tavern-card-validator.test.js
new file mode 100644
index 000000000..6eadae6d2
--- /dev/null
+++ b/tests/tavern-card-validator.test.js
@@ -0,0 +1,251 @@
+import { describe, test, expect } from '@jest/globals';
+import { TavernCardValidator } from '../src/validator/TavernCardValidator';
+
+const V1_FIELDS = ['name', 'description', 'personality', 'scenario', 'first_mes', 'mes_example'];
+
+const V2_DATA_FIELDS = [
+    'name', 'description', 'personality', 'scenario', 'first_mes', 'mes_example',
+    'creator_notes', 'system_prompt', 'post_history_instructions',
+    'alternate_greetings', 'tags', 'creator', 'character_version', 'extensions',
+];
+
+function makeV1Card() {
+    return Object.fromEntries(V1_FIELDS.map(f => [f, '']));
+}
+
+function makeV2Card() {
+    return {
+        spec: 'chara_card_v2',
+        spec_version: '2.0',
+        data: {
+            ...Object.fromEntries(V2_DATA_FIELDS.map(f => [f, ''])),
+            alternate_greetings: [],
+            tags: [],
+            extensions: {},
+        },
+    };
+}
+
+function makeV3Card() {
+    return {
+        spec: 'chara_card_v3',
+        spec_version: '3.0',
+        data: {},
+    };
+}
+
+describe('TavernCardValidator', () => {
+    describe('validate', () => {
+        test('returns 1 for valid V1 card', () => {
+            const v = new TavernCardValidator(makeV1Card());
+            expect(v.validate()).toBe(1);
+        });
+
+        test('returns 2 for valid V2 card', () => {
+            const v = new TavernCardValidator(makeV2Card());
+            expect(v.validate()).toBe(2);
+        });
+
+        test('returns 3 for valid V3 card', () => {
+            const v = new TavernCardValidator(makeV3Card());
+            expect(v.validate()).toBe(3);
+        });
+
+        test('returns false for empty object', () => {
+            const v = new TavernCardValidator({});
+            expect(v.validate()).toBe(false);
+        });
+
+        test('prefers V1 when card satisfies both V1 and V2', () => {
+            const card = { ...makeV1Card(), ...makeV2Card() };
+            const v = new TavernCardValidator(card);
+            expect(v.validate()).toBe(1);
+        });
+    });
+
+    describe('validateV1', () => {
+        test('accepts card with all required fields', () => {
+            const v = new TavernCardValidator(makeV1Card());
+            expect(v.validateV1()).toBe(true);
+        });
+
+        for (const field of V1_FIELDS) {
+            test(`rejects card missing ${field}`, () => {
+                const card = makeV1Card();
+                delete card[field];
+                const v = new TavernCardValidator(card);
+                expect(v.validateV1()).toBe(false);
+                expect(v.lastValidationError).toBe(field);
+            });
+        }
+    });
+
+    describe('validateV2', () => {
+        test('accepts valid V2 card', () => {
+            const v = new TavernCardValidator(makeV2Card());
+            expect(v.validateV2()).toBe(true);
+        });
+
+        test('rejects wrong spec string', () => {
+            const card = makeV2Card();
+            card.spec = 'chara_card_v1';
+            const v = new TavernCardValidator(card);
+            expect(v.validateV2()).toBe(false);
+            expect(v.lastValidationError).toBe('spec');
+        });
+
+        test('rejects wrong spec_version', () => {
+            const card = makeV2Card();
+            card.spec_version = '1.0';
+            const v = new TavernCardValidator(card);
+            expect(v.validateV2()).toBe(false);
+            expect(v.lastValidationError).toBe('spec_version');
+        });
+
+        test('rejects missing data', () => {
+            const card = makeV2Card();
+            delete card.data;
+            const v = new TavernCardValidator(card);
+            expect(v.validateV2()).toBe(false);
+        });
+
+        for (const field of V2_DATA_FIELDS) {
+            test(`rejects card missing data.${field}`, () => {
+                const card = makeV2Card();
+                delete card.data[field];
+                const v = new TavernCardValidator(card);
+                expect(v.validateV2()).toBe(false);
+                expect(v.lastValidationError).toBe(`data.${field}`);
+            });
+        }
+
+        test('rejects non-array alternate_greetings', () => {
+            const card = makeV2Card();
+            card.data.alternate_greetings = 'not an array';
+            const v = new TavernCardValidator(card);
+            expect(v.validateV2()).toBe(false);
+        });
+
+        test('rejects non-array tags', () => {
+            const card = makeV2Card();
+            card.data.tags = 'not an array';
+            const v = new TavernCardValidator(card);
+            expect(v.validateV2()).toBe(false);
+        });
+
+        test('rejects non-object extensions', () => {
+            const card = makeV2Card();
+            card.data.extensions = 'not an object';
+            const v = new TavernCardValidator(card);
+            expect(v.validateV2()).toBe(false);
+        });
+
+        test('accepts card with optional character_book', () => {
+            const card = makeV2Card();
+            card.data.character_book = {
+                extensions: {},
+                entries: [],
+            };
+            const v = new TavernCardValidator(card);
+            expect(v.validateV2()).toBe(true);
+        });
+
+        test('rejects character_book missing entries', () => {
+            const card = makeV2Card();
+            card.data.character_book = { extensions: {} };
+            const v = new TavernCardValidator(card);
+            expect(v.validateV2()).toBe(false);
+            expect(v.lastValidationError).toBe('data.character_book.entries');
+        });
+
+        test('rejects character_book missing extensions', () => {
+            const card = makeV2Card();
+            card.data.character_book = { entries: [] };
+            const v = new TavernCardValidator(card);
+            expect(v.validateV2()).toBe(false);
+            expect(v.lastValidationError).toBe('data.character_book.extensions');
+        });
+
+        test('rejects character_book with non-array entries', () => {
+            const card = makeV2Card();
+            card.data.character_book = { extensions: {}, entries: 'not array' };
+            const v = new TavernCardValidator(card);
+            expect(v.validateV2()).toBe(false);
+        });
+
+        test('rejects character_book with non-object extensions', () => {
+            const card = makeV2Card();
+            card.data.character_book = { extensions: 'not object', entries: [] };
+            const v = new TavernCardValidator(card);
+            expect(v.validateV2()).toBe(false);
+        });
+    });
+
+    describe('validateV3', () => {
+        test('accepts valid V3 card', () => {
+            const v = new TavernCardValidator(makeV3Card());
+            expect(v.validateV3()).toBe(true);
+        });
+
+        test('rejects wrong spec string', () => {
+            const card = makeV3Card();
+            card.spec = 'chara_card_v2';
+            const v = new TavernCardValidator(card);
+            expect(v.validateV3()).toBe(false);
+            expect(v.lastValidationError).toBe('spec');
+        });
+
+        test('rejects spec_version below 3.0', () => {
+            const card = makeV3Card();
+            card.spec_version = '2.9';
+            const v = new TavernCardValidator(card);
+            expect(v.validateV3()).toBe(false);
+            expect(v.lastValidationError).toBe('spec_version');
+        });
+
+        test('rejects spec_version at or above 4.0', () => {
+            const card = makeV3Card();
+            card.spec_version = '4.0';
+            const v = new TavernCardValidator(card);
+            expect(v.validateV3()).toBe(false);
+        });
+
+        test('accepts spec_version 3.5', () => {
+            const card = makeV3Card();
+            card.spec_version = '3.5';
+            const v = new TavernCardValidator(card);
+            expect(v.validateV3()).toBe(true);
+        });
+
+        test('rejects missing data', () => {
+            const card = makeV3Card();
+            delete card.data;
+            const v = new TavernCardValidator(card);
+            expect(v.validateV3()).toBe(false);
+        });
+
+        test('rejects non-object data', () => {
+            const card = makeV3Card();
+            card.data = 'not an object';
+            const v = new TavernCardValidator(card);
+            expect(v.validateV3()).toBe(false);
+        });
+    });
+
+    describe('lastValidationError', () => {
+        test('is null after successful validation', () => {
+            const v = new TavernCardValidator(makeV1Card());
+            v.validate();
+            expect(v.lastValidationError).toBeNull();
+        });
+
+        test('is reset on each validate call', () => {
+            const v = new TavernCardValidator({});
+            v.validate();
+            expect(v.lastValidationError).not.toBeNull();
+            v.card = makeV1Card();
+            v.validate();
+            expect(v.lastValidationError).toBeNull();
+        });
+    });
+});