fix(dataflows): honour omitted optionals in the Alpha Vantage global-news path

tests/test_alpha_vantage_hardening.py

@@ -12,6 +12,7 @@
 
 import tradingagents.dataflows.alpha_vantage_common as av
 import tradingagents.dataflows.alpha_vantage_fundamentals as avf
+import tradingagents.dataflows.alpha_vantage_news as avn
 import tradingagents.dataflows.alpha_vantage_stock as avs
 
 
@@ -133,3 +134,33 @@ def test_unparseable_body_is_never_served_untrimmed(monkeypatch):
 def test_empty_body_still_passes_through(monkeypatch):
     monkeypatch.setattr(avs, "_make_api_request", lambda *a, **k: "")
     assert avs.get_stock("IBM", "2024-05-09", "2024-05-10") == ""
+
+
+def _capture_global_news_params(monkeypatch, config):
+    captured = {}
+    monkeypatch.setattr(avn, "_make_api_request", lambda fn, params: captured.update(params) or "{}")
+    monkeypatch.setattr(avn, "get_config", lambda: config)
+    return captured
+
+
+@pytest.mark.unit
+def test_global_news_omitted_optionals_resolve_from_config(monkeypatch):
+    # The get_global_news tool marks look_back_days/limit optional and forwards
+    # None; Alpha Vantage must resolve them from config like the yfinance path
+    # does, instead of crashing on timedelta(days=None).
+    captured = _capture_global_news_params(
+        monkeypatch, {"global_news_lookback_days": 7, "global_news_article_limit": 10}
+    )
+    avn.get_global_news("2026-01-10", None, None)
+    assert captured["limit"] == "10"
+    assert captured["time_from"] == "20260103T0000"  # 2026-01-10 minus 7 days
+
+
+@pytest.mark.unit
+def test_global_news_explicit_optionals_win_over_config(monkeypatch):
+    captured = _capture_global_news_params(
+        monkeypatch, {"global_news_lookback_days": 7, "global_news_article_limit": 10}
+    )
+    avn.get_global_news("2026-01-10", 3, 5)
+    assert captured["limit"] == "5"
+    assert captured["time_from"] == "20260107T0000"  # 2026-01-10 minus 3 days

tradingagents/dataflows/alpha_vantage_news.py

@@ -1,4 +1,5 @@
 from .alpha_vantage_common import _make_api_request, format_datetime_for_api
+from .config import get_config
 
 
 def get_news(ticker, start_date, end_date) -> dict[str, str] | str:
@@ -23,21 +24,31 @@ def get_news(ticker, start_date, end_date) -> dict[str, str] | str:
 
     return _make_api_request("NEWS_SENTIMENT", params)
 
-def get_global_news(curr_date, look_back_days: int = 7, limit: int = 50) -> dict[str, str] | str:
+def get_global_news(
+    curr_date, look_back_days: int | None = None, limit: int | None = None
+) -> dict[str, str] | str:
     """Returns global market news & sentiment data without ticker-specific filtering.
 
     Covers broad market topics like financial markets, economy, and more.
 
     Args:
         curr_date: Current date in yyyy-mm-dd format.
-        look_back_days: Number of days to look back (default 7).
-        limit: Maximum number of articles (default 50).
+        look_back_days: Number of days to look back. ``None`` falls back to
+            ``global_news_lookback_days`` from the active config.
+        limit: Maximum number of articles. ``None`` falls back to
+            ``global_news_article_limit`` from the active config.
 
     Returns:
         Dictionary containing global news sentiment data or JSON string.
     """
     from datetime import datetime, timedelta
 
+    config = get_config()
+    if look_back_days is None:
+        look_back_days = config["global_news_lookback_days"]
+    if limit is None:
+        limit = config["global_news_article_limit"]
+
     # Calculate start date
     curr_dt = datetime.strptime(curr_date, "%Y-%m-%d")
     start_dt = curr_dt - timedelta(days=look_back_days)