diff --git a/lib/services/pax8-factory.test.ts b/lib/services/pax8-factory.test.ts
new file mode 100644
index 0000000..dd2d6d9
--- /dev/null
+++ b/lib/services/pax8-factory.test.ts
@@ -0,0 +1,61 @@
+import { describe, it, expect, beforeEach } from 'vitest';
+import { isPax8Configured, getPax8Client, _resetPax8Client } from './pax8-factory';
+
+beforeEach(() => {
+  delete process.env.PAX8_CLIENT_ID;
+  delete process.env.PAX8_CLIENT_SECRET;
+  _resetPax8Client();
+});
+
+describe('isPax8Configured', () => {
+  it('returns false when neither env var is set', () => {
+    expect(isPax8Configured()).toBe(false);
+  });
+
+  it('returns false when only PAX8_CLIENT_ID is set', () => {
+    process.env.PAX8_CLIENT_ID = 'id1';
+    expect(isPax8Configured()).toBe(false);
+  });
+
+  it('returns false when only PAX8_CLIENT_SECRET is set', () => {
+    process.env.PAX8_CLIENT_SECRET = 'secret1';
+    expect(isPax8Configured()).toBe(false);
+  });
+
+  it('returns true when both env vars are set', () => {
+    process.env.PAX8_CLIENT_ID = 'id1';
+    process.env.PAX8_CLIENT_SECRET = 'secret1';
+    expect(isPax8Configured()).toBe(true);
+  });
+});
+
+describe('getPax8Client', () => {
+  it('throws the exact configuration error when not configured', () => {
+    expect(() => getPax8Client()).toThrow(
+      'PAX8 is not configured — set PAX8_CLIENT_ID and PAX8_CLIENT_SECRET'
+    );
+  });
+
+  it('returns a client instance when both env vars are set', () => {
+    process.env.PAX8_CLIENT_ID = 'id1';
+    process.env.PAX8_CLIENT_SECRET = 'secret1';
+    expect(getPax8Client()).toBeDefined();
+  });
+
+  it('returns the same cached instance on repeated calls', () => {
+    process.env.PAX8_CLIENT_ID = 'id1';
+    process.env.PAX8_CLIENT_SECRET = 'secret1';
+    const first = getPax8Client();
+    const second = getPax8Client();
+    expect(second).toBe(first);
+  });
+
+  it('rebuilds a new instance after _resetPax8Client()', () => {
+    process.env.PAX8_CLIENT_ID = 'id1';
+    process.env.PAX8_CLIENT_SECRET = 'secret1';
+    const first = getPax8Client();
+    _resetPax8Client();
+    const second = getPax8Client();
+    expect(second).not.toBe(first);
+  });
+});