diff --git a/tests/test_notes.py b/tests/test_notes.py
new file mode 100644
index 0000000..3ea6436
--- /dev/null
+++ b/tests/test_notes.py
@@ -0,0 +1,69 @@
+"""Tests for FR-6 + R-2 (Note entity, polymorphic parent validation)."""
+
+from __future__ import annotations
+
+import pytest
+from httpx import AsyncClient
+
+
+@pytest.mark.asyncio
+async def test_create_note_with_valid_parent(
+    client: AsyncClient, auth_headers: dict[str, str], seed_data: dict
+) -> None:
+    acc_id = seed_data["account_ids"][0]
+    resp = await client.post(
+        "/api/v1/notes/",
+        json={"body": "Great call", "parent_type": "account", "parent_id": acc_id},
+        headers=auth_headers,
+    )
+    assert resp.status_code == 201, resp.text
+    body = resp.json()
+    assert body["parent_type"] == "account"
+    assert body["parent_id"] == acc_id
+
+
+@pytest.mark.asyncio
+async def test_create_note_with_invalid_parent(
+    client: AsyncClient, auth_headers: dict[str, str]
+) -> None:
+    """R-2: parent_type+parent_id must point to an existing entity; else 404."""
+    resp = await client.post(
+        "/api/v1/notes/",
+        json={"body": "Note into the void", "parent_type": "account", "parent_id": 99999},
+        headers=auth_headers,
+    )
+    assert resp.status_code == 404
+
+
+@pytest.mark.asyncio
+async def test_list_notes_for_parent(client: AsyncClient, seed_data: dict) -> None:
+    acc_id = seed_data["account_ids"][0]
+    resp = await client.get(
+        f"/api/v1/notes/?parent_type=account&parent_id={acc_id}",
+        headers=seed_data["headers"],
+    )
+    assert resp.status_code == 200
+    body = resp.json()
+    assert all(n["parent_type"] == "account" and n["parent_id"] == acc_id for n in body)
+
+
+@pytest.mark.asyncio
+async def test_polymorphic_note_for_account_vs_contact(
+    client: AsyncClient, auth_headers: dict[str, str], seed_data: dict
+) -> None:
+    acc_id = seed_data["account_ids"][0]
+    contact_id = seed_data["contact_ids"][0]
+    n_acc = await client.post(
+        "/api/v1/notes/",
+        json={"body": "Account note", "parent_type": "account", "parent_id": acc_id},
+        headers=auth_headers,
+    )
+    n_contact = await client.post(
+        "/api/v1/notes/",
+        json={"body": "Contact note", "parent_type": "contact", "parent_id": contact_id},
+        headers=auth_headers,
+    )
+    assert n_acc.status_code == 201, n_acc.text
+    assert n_contact.status_code == 201, n_contact.text
+    assert n_acc.json()["parent_type"] == "account"
+    assert n_contact.json()["parent_type"] == "contact"