Consolidate Odysseus agent harness and tool contracts

tests/test_calendar_ordinal_date_guard.py

@@ -0,0 +1,19 @@
+from src.agent_loop import _parse_ambiguous_calendar_date_ask_user
+
+
+def test_next_month_ordinal_weekday_is_not_treated_as_missing_date() -> None:
+    prompt = (
+        "Create a calendar event on the last Wednesday of next month at "
+        "3:15 PM."
+    )
+
+    assert _parse_ambiguous_calendar_date_ask_user(prompt) is None
+
+
+def test_genuinely_missing_next_month_day_still_asks_user() -> None:
+    prompt = "Create a dinner reservation next month at 7 PM."
+
+    tool_call = _parse_ambiguous_calendar_date_ask_user(prompt)
+
+    assert tool_call is not None
+    assert tool_call[0] == "ask_user"