diff --git a/backend/magic_plan/tests/test_magic_plan_client.py b/backend/magic_plan/tests/test_magic_plan_client.py
new file mode 100644
index 00000000..f8f35432
--- /dev/null
+++ b/backend/magic_plan/tests/test_magic_plan_client.py
@@ -0,0 +1,133 @@
+import json
+from pathlib import Path
+from typing import Any
+from unittest.mock import MagicMock, patch
+
+import pytest
+import requests
+
+from backend.magic_plan.magic_plan_client import MagicPlanClient
+from datatypes.magicplan.api.response import MagicPlan, PlansListResponse
+
+FIXTURE_DIR = Path(__file__).parents[2] / "magic_plan"
+BASE_URL = "https://cloud.magicplan.app/api/v2"
+CUSTOMER_ID = "test-customer"
+API_KEY = "test-key"
+
+
+def _load_fixture(name: str) -> dict[str, Any]:
+    return json.loads((FIXTURE_DIR / name).read_text())
+
+
+def _make_client(mock_session: MagicMock) -> MagicPlanClient:
+    with patch("backend.magic_plan.magic_plan_client.requests.Session", return_value=mock_session):
+        return MagicPlanClient(customer_id=CUSTOMER_ID, api_key=API_KEY)
+
+
+@pytest.fixture()
+def mock_session() -> MagicMock:
+    return MagicMock(spec=requests.Session)
+
+
+@pytest.fixture()
+def client(mock_session: MagicMock) -> MagicPlanClient:
+    return _make_client(mock_session)
+
+
+# --- constructor ---
+
+
+def test_customer_header_set_on_session(mock_session: MagicMock) -> None:
+    # Act
+    _make_client(mock_session)
+    # Assert
+    mock_session.headers.update.assert_called_once_with({"customer": CUSTOMER_ID})
+
+
+# --- get_plans ---
+
+
+def test_get_plans_calls_correct_url(client: MagicPlanClient, mock_session: MagicMock) -> None:
+    # Arrange
+    plans_data = _load_fixture("magicplan_api_plans_response_example.json")["data"]
+    mock_session.get.return_value.json.return_value = {"message": "OK", "data": plans_data}
+    # Act
+    client.get_plans()
+    # Assert
+    mock_session.get.assert_called_once_with(
+        f"{BASE_URL}/plans", params={"key": API_KEY}
+    )
+
+
+def test_get_plans_calls_raise_for_status(client: MagicPlanClient, mock_session: MagicMock) -> None:
+    # Arrange
+    plans_data = _load_fixture("magicplan_api_plans_response_example.json")["data"]
+    mock_session.get.return_value.json.return_value = {"message": "OK", "data": plans_data}
+    # Act
+    client.get_plans()
+    # Assert
+    mock_session.get.return_value.raise_for_status.assert_called_once()
+
+
+def test_get_plans_returns_plans_list_response(client: MagicPlanClient, mock_session: MagicMock) -> None:
+    # Arrange
+    plans_data = _load_fixture("magicplan_api_plans_response_example.json")["data"]
+    mock_session.get.return_value.json.return_value = {"message": "OK", "data": plans_data}
+    # Act
+    result = client.get_plans()
+    # Assert
+    assert isinstance(result, PlansListResponse)
+    assert len(result.plans) == 1
+
+
+def test_get_plans_propagates_http_error(client: MagicPlanClient, mock_session: MagicMock) -> None:
+    # Arrange
+    mock_session.get.return_value.raise_for_status.side_effect = requests.HTTPError("404")
+    # Act / Assert
+    with pytest.raises(requests.HTTPError):
+        client.get_plans()
+
+
+# --- get_plan ---
+
+
+def test_get_plan_calls_correct_url(client: MagicPlanClient, mock_session: MagicMock) -> None:
+    # Arrange
+    plan_data = _load_fixture("magicplan_api_plan_response_example.json")["data"]
+    mock_session.get.return_value.json.return_value = {"message": "OK", "data": plan_data}
+    plan_id = "a7285ed1-878d-47eb-8aa6-85ef9e187516"
+    # Act
+    client.get_plan(plan_id)
+    # Assert
+    mock_session.get.assert_called_once_with(
+        f"{BASE_URL}/plans/{plan_id}", params={"key": API_KEY}
+    )
+
+
+def test_get_plan_calls_raise_for_status(client: MagicPlanClient, mock_session: MagicMock) -> None:
+    # Arrange
+    plan_data = _load_fixture("magicplan_api_plan_response_example.json")["data"]
+    mock_session.get.return_value.json.return_value = {"message": "OK", "data": plan_data}
+    # Act
+    client.get_plan("a7285ed1-878d-47eb-8aa6-85ef9e187516")
+    # Assert
+    mock_session.get.return_value.raise_for_status.assert_called_once()
+
+
+def test_get_plan_returns_magic_plan(client: MagicPlanClient, mock_session: MagicMock) -> None:
+    # Arrange
+    plan_data = _load_fixture("magicplan_api_plan_response_example.json")["data"]
+    mock_session.get.return_value.json.return_value = {"message": "OK", "data": plan_data}
+    # Act
+    result = client.get_plan("a7285ed1-878d-47eb-8aa6-85ef9e187516")
+    # Assert
+    assert isinstance(result, MagicPlan)
+    assert result.plan.id == "a7285ed1-878d-47eb-8aa6-85ef9e187516"
+
+
+def test_get_plan_propagates_http_error(client: MagicPlanClient, mock_session: MagicMock) -> None:
+    # Arrange
+    mock_session.get.return_value.raise_for_status.side_effect = requests.HTTPError("500")
+    # Act / Assert
+    with pytest.raises(requests.HTTPError):
+        client.get_plan("some-id")