feat(mcp): event CRUD tools

Five new tools (events weren't in fable-mcp before). Split
start_date + start_time inputs combine into a naive datetime that
services/events.py interprets in the user's local timezone.

Sentinels for update:
  - empty strings → leave unchanged
  - duration_minutes=-1 → leave unchanged
  - duration_minutes=0 → set to point event (NULL duration)
  - start_date/start_time must BOTH be set to move the event

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/test_mcp_tool_events.py

@@ -0,0 +1,158 @@
+"""Tests for fable_*_event tools."""
+from datetime import datetime
+from unittest.mock import AsyncMock, MagicMock, patch
+
+import pytest
+
+from fabledassistant.mcp._context import _user_id_ctx
+from fabledassistant.mcp.tools.events import (
+    fable_list_events, fable_create_event, fable_get_event,
+    fable_update_event, fable_delete_event,
+)
+
+
+@pytest.fixture(autouse=True)
+def _bind_user():
+    token = _user_id_ctx.set(7)
+    yield
+    _user_id_ctx.reset(token)
+
+
+def _fake_event(**overrides) -> MagicMock:
+    e = MagicMock()
+    base = {
+        "id": 1, "title": "ev", "start_dt": "2026-06-01T10:00:00",
+        "duration_minutes": 30, "all_day": False,
+        "location": "", "description": "",
+    }
+    base.update(overrides)
+    e.to_dict.return_value = base
+    return e
+
+
+@pytest.mark.asyncio
+async def test_list_events_passes_datetime_range():
+    mock = AsyncMock(return_value=[
+        {"id": 1, "title": "morning standup"},
+    ])
+    with patch("fabledassistant.mcp.tools.events.events_svc.list_events", mock):
+        out = await fable_list_events(date_from="2026-06-01", date_to="2026-06-08")
+    args, _ = mock.call_args
+    assert args[0] == 7  # user_id
+    assert args[1] == datetime(2026, 6, 1)
+    assert args[2] == datetime(2026, 6, 8)
+    assert out["total"] == 1
+
+
+@pytest.mark.asyncio
+async def test_create_event_combines_date_and_time():
+    e = _fake_event()
+    mock = AsyncMock(return_value=e)
+    with patch("fabledassistant.mcp.tools.events.events_svc.create_event", mock):
+        await fable_create_event(
+            title="standup", start_date="2026-06-01", start_time="09:30",
+            duration_minutes=15,
+        )
+    kwargs = mock.call_args.kwargs
+    assert kwargs["start_dt"] == datetime(2026, 6, 1, 9, 30)
+    assert kwargs["duration_minutes"] == 15
+
+
+@pytest.mark.asyncio
+async def test_create_event_zero_duration_means_point_event():
+    """duration_minutes=0 must map to None at the service layer (NULL = point)."""
+    e = _fake_event()
+    mock = AsyncMock(return_value=e)
+    with patch("fabledassistant.mcp.tools.events.events_svc.create_event", mock):
+        await fable_create_event(title="x", start_date="2026-06-01")
+    assert mock.call_args.kwargs["duration_minutes"] is None
+
+
+@pytest.mark.asyncio
+async def test_get_event_raises_when_not_found():
+    with patch(
+        "fabledassistant.mcp.tools.events.events_svc.get_event",
+        AsyncMock(return_value=None),
+    ):
+        with pytest.raises(ValueError, match="event 999 not found"):
+            await fable_get_event(event_id=999)
+
+
+@pytest.mark.asyncio
+async def test_update_event_only_sends_non_default_fields():
+    e = _fake_event()
+    mock = AsyncMock(return_value=e)
+    with patch("fabledassistant.mcp.tools.events.events_svc.update_event", mock):
+        await fable_update_event(event_id=1, title="new title")
+    args, kwargs = mock.call_args
+    assert args == (7, 1)
+    assert kwargs == {"title": "new title"}
+
+
+@pytest.mark.asyncio
+async def test_update_event_duration_minus_one_means_unchanged():
+    e = _fake_event()
+    mock = AsyncMock(return_value=e)
+    with patch("fabledassistant.mcp.tools.events.events_svc.update_event", mock):
+        await fable_update_event(event_id=1, duration_minutes=-1)
+    assert "duration_minutes" not in mock.call_args.kwargs
+
+
+@pytest.mark.asyncio
+async def test_update_event_duration_zero_clears_to_point():
+    """duration_minutes=0 means "set to point event" (NULL)."""
+    e = _fake_event()
+    mock = AsyncMock(return_value=e)
+    with patch("fabledassistant.mcp.tools.events.events_svc.update_event", mock):
+        await fable_update_event(event_id=1, duration_minutes=0)
+    assert mock.call_args.kwargs["duration_minutes"] is None
+
+
+@pytest.mark.asyncio
+async def test_update_event_requires_both_date_and_time_to_move():
+    e = _fake_event()
+    mock = AsyncMock(return_value=e)
+    with patch("fabledassistant.mcp.tools.events.events_svc.update_event", mock):
+        await fable_update_event(event_id=1, start_date="2026-06-02")
+        # Only start_date, no start_time → start_dt NOT in fields
+        assert "start_dt" not in mock.call_args.kwargs
+
+        mock.reset_mock()
+        await fable_update_event(
+            event_id=1, start_date="2026-06-02", start_time="11:00",
+        )
+        assert mock.call_args.kwargs["start_dt"] == datetime(2026, 6, 2, 11)
+
+
+@pytest.mark.asyncio
+async def test_update_event_raises_when_not_found():
+    with patch(
+        "fabledassistant.mcp.tools.events.events_svc.update_event",
+        AsyncMock(return_value=None),
+    ):
+        with pytest.raises(ValueError, match="event 999 not found"):
+            await fable_update_event(event_id=999, title="x")
+
+
+@pytest.mark.asyncio
+async def test_delete_event_checks_existence_then_returns_confirmation():
+    fake = _fake_event()
+    with patch(
+        "fabledassistant.mcp.tools.events.events_svc.get_event",
+        AsyncMock(return_value=fake),
+    ), patch(
+        "fabledassistant.mcp.tools.events.events_svc.delete_event",
+        AsyncMock(return_value=None),
+    ):
+        result = await fable_delete_event(event_id=7)
+    assert result == "Event 7 deleted."
+
+
+@pytest.mark.asyncio
+async def test_delete_event_raises_when_not_found():
+    with patch(
+        "fabledassistant.mcp.tools.events.events_svc.get_event",
+        AsyncMock(return_value=None),
+    ):
+        with pytest.raises(ValueError, match="event 999 not found"):
+            await fable_delete_event(event_id=999)