fix(mcp): list_events tz-aware UTC range + end-of-day inclusive

Phase 6 smoke caught:

  Error executing tool list_events:
    can't compare offset-naive and offset-aware datetimes

Event.start_dt is stored timezone-aware; the wrapper was passing naive
datetimes built from datetime.fromisoformat("YYYY-MM-DD"), so the SQL
comparison crashed. Also: the docstring promises "date_to inclusive at
end-of-day" but the code was using midnight-of-date_to, which would
silently miss same-day events after midnight.

Extracted the range math into _day_range_utc() so create/update_event's
_combine() can stay as-is (it stays naive — the service localizes
create/update inputs against the user's tz, that path didn't crash).

Test updated to match: assert tz-aware UTC datetimes and the +24h
bump for end-of-day-inclusive semantics.

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

src/fabledassistant/mcp/tools/events.py

@@ -17,18 +17,40 @@ For update, sentinels:
 """
 from __future__ import annotations
 
-from datetime import datetime
+from datetime import datetime, timedelta, timezone
 
 from fabledassistant.mcp._context import current_user_id
 from fabledassistant.services import events as events_svc
 
 
 def _combine(start_date: str, start_time: str) -> datetime:
-    """Combine YYYY-MM-DD + HH:MM into a naive datetime."""
+    """Combine YYYY-MM-DD + HH:MM into a naive datetime.
+
+    The events service interprets naive datetimes for create/update against
+    the user's configured timezone, so we don't attach tzinfo here.
+    """
     t = start_time or "00:00"
     return datetime.fromisoformat(f"{start_date}T{t}:00")
 
 
+def _day_range_utc(date_from: str, date_to: str) -> tuple[datetime, datetime]:
+    """Return a UTC datetime range [start_of_date_from, end_of_date_to).
+
+    Event.start_dt is stored timezone-aware in the DB; comparing it against a
+    naive datetime raises TypeError. We anchor the range in UTC, which is a
+    reasonable default — refining to the user's local timezone for the
+    range boundaries is a separate improvement.
+    """
+    start = datetime.fromisoformat(date_from).replace(tzinfo=timezone.utc)
+    # `date_to` is inclusive at the day level — bump by 24h so events later
+    # on date_to are included.
+    end = (
+        datetime.fromisoformat(date_to).replace(tzinfo=timezone.utc)
+        + timedelta(days=1)
+    )
+    return start, end
+
+
 def _event_dict(event) -> dict:
     """Render an Event model to a dict, handling list_events (already dicts)."""
     return event if isinstance(event, dict) else event.to_dict()
@@ -41,8 +63,7 @@ async def list_events(date_from: str, date_to: str) -> dict:
     Recurring events are expanded into individual occurrences within the range.
     """
     uid = current_user_id()
-    start = datetime.fromisoformat(date_from)
-    end = datetime.fromisoformat(date_to)
+    start, end = _day_range_utc(date_from, date_to)
     rows = await events_svc.list_events(uid, start, end)
     return {"events": [_event_dict(e) for e in rows], "total": len(rows)}
 

tests/test_mcp_tool_events.py

@@ -31,7 +31,10 @@ def _fake_event(**overrides) -> MagicMock:
 
 
 @pytest.mark.asyncio
-async def test_list_events_passes_datetime_range():
+async def test_list_events_passes_timezone_aware_range():
+    """Range must be tz-aware (UTC) and date_to inclusive at end-of-day —
+    Event.start_dt is tz-aware in the DB; naive comparisons raise TypeError."""
+    from datetime import timezone
     mock = AsyncMock(return_value=[
         {"id": 1, "title": "morning standup"},
     ])
@@ -39,8 +42,9 @@ async def test_list_events_passes_datetime_range():
         out = await 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 args[1] == datetime(2026, 6, 1, tzinfo=timezone.utc)
+    # date_to is end-of-day inclusive → start of 2026-06-09 (24h past start of 2026-06-08)
+    assert args[2] == datetime(2026, 6, 9, tzinfo=timezone.utc)
     assert out["total"] == 1