diff --git a/backend/app/api/mcp_server.py b/backend/app/api/mcp_server.py
index f5f31c6..d2faac1 100644
--- a/backend/app/api/mcp_server.py
+++ b/backend/app/api/mcp_server.py
@@ -8,8 +8,9 @@ from sqlalchemy import select, and_
 
 from app.core.database import AsyncSessionLocal
 from app.models.todos import TodoItem
-from app.models.notes import NoteItem
-from app.models.shopping import ShoppingList, ListItem, Product
+
+_VALID_STATUSES = {"pending", "done", "cancelled"}
+_VALID_PRIORITIES = {"low", "medium", "high"}
 
 mcp = FastMCP("HomeHub", stateless_http=True)
 
@@ -79,6 +80,8 @@ async def create_todo(
     domain: str | None = None,
 ) -> str:
     """Crée une tâche. due_date en ISO 8601 (ex: 2025-06-01T10:00:00Z). priority: low/medium/high."""
+    if priority and priority not in _VALID_PRIORITIES:
+        return _dumps({"error": f"Priorité invalide : {priority}. Valeurs: low/medium/high"})
     async with AsyncSessionLocal() as session:
         parsed_due = None
         if due_date:
@@ -121,6 +124,10 @@ async def update_todo(
         item = await session.get(TodoItem, todo_id)
         if not item:
             return _dumps({"error": f"Tâche introuvable : {id}"})
+        if status is not None and status not in _VALID_STATUSES:
+            return _dumps({"error": f"Statut invalide : {status}. Valeurs: pending/done/cancelled"})
+        if priority is not None and priority not in _VALID_PRIORITIES:
+            return _dumps({"error": f"Priorité invalide : {priority}. Valeurs: low/medium/high"})
         if title is not None:
             item.title = title
         if status is not None:
diff --git a/backend/tests/conftest.py b/backend/tests/conftest.py
index 061d1e9..a5c2d39 100644
--- a/backend/tests/conftest.py
+++ b/backend/tests/conftest.py
@@ -13,7 +13,7 @@ def make_test_engine():
     return create_async_engine(settings.database_url, poolclass=NullPool)
 
 
-@pytest.fixture(autouse=True)
+@pytest.fixture
 async def mcp_nullpool_session():
     """Remplace AsyncSessionLocal dans mcp_server par un sessionmaker NullPool
     pour éviter les conflits d'event loop entre tests."""
diff --git a/backend/tests/test_mcp.py b/backend/tests/test_mcp.py
index f551ef6..2f73e11 100644
--- a/backend/tests/test_mcp.py
+++ b/backend/tests/test_mcp.py
@@ -1,8 +1,21 @@
 import json
 import pytest
+from sqlalchemy import delete
 from app.api.mcp_server import (
     get_todos, create_todo, update_todo, postpone_todo, delete_todo,
 )
+from app.core.database import AsyncSessionLocal
+from app.models.todos import TodoItem
+
+pytestmark = pytest.mark.usefixtures("mcp_nullpool_session")
+
+
+@pytest.fixture(autouse=True)
+async def cleanup_mcp_todos():
+    yield
+    async with AsyncSessionLocal() as session:
+        await session.execute(delete(TodoItem).where(TodoItem.title.like("TEST_MCP_%")))
+        await session.commit()
 
 
 async def test_get_todos_retourne_liste_json():