fix: make news article limits and lookback window configurable (fixes #562)

Three parameters were hardcoded with no way to override via config:
- count=20 in yf.Ticker.get_news() inside get_news_yfinance
- look_back_days=7 default in get_global_news_yfinance
- limit=10 default in get_global_news_yfinance

Add three new keys to DEFAULT_CONFIG:
- news_article_limit (default 20): max articles per ticker for get_news
- global_news_lookback_days (default 7): lookback window for get_global_news
- global_news_article_limit (default 10): max global articles for get_global_news

Both yfinance and alpha_vantage news implementations now read these values
from config, allowing users running weekly/monthly strategies to increase
coverage without modifying library source code.

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:
     """Returns live and historical market news & sentiment data from premier news outlets worldwide.
@@ -22,21 +23,27 @@ 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, limit: int = 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 (defaults to global_news_lookback_days config).
+        limit: Maximum number of articles (defaults to global_news_article_limit 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.get("global_news_lookback_days", 7)
+    if limit is None:
+        limit = config.get("global_news_article_limit", 50)
+
     # Calculate start date
     curr_dt = datetime.strptime(curr_date, "%Y-%m-%d")
     start_dt = curr_dt - timedelta(days=look_back_days)

tradingagents/dataflows/yfinance_news.py

@@ -5,6 +5,7 @@ from datetime import datetime
 from dateutil.relativedelta import relativedelta
 
 from .stockstats_utils import yf_retry
+from .config import get_config
 
 
 def _extract_article_data(article: dict) -> dict:
@@ -66,7 +67,8 @@ def get_news_yfinance(
     """
     try:
         stock = yf.Ticker(ticker)
-        news = yf_retry(lambda: stock.get_news(count=20))
+        count = get_config().get("news_article_limit", 20)
+        news = yf_retry(lambda: stock.get_news(count=count))
 
         if not news:
             return f"No news found for {ticker}"
@@ -106,20 +108,25 @@ def get_news_yfinance(
 
 def get_global_news_yfinance(
     curr_date: str,
-    look_back_days: int = 7,
-    limit: int = 10,
+    look_back_days: int = None,
+    limit: int = None,
 ) -> str:
     """
     Retrieve global/macro economic news using yfinance Search.
 
     Args:
         curr_date: Current date in yyyy-mm-dd format
-        look_back_days: Number of days to look back
-        limit: Maximum number of articles to return
+        look_back_days: Number of days to look back (defaults to global_news_lookback_days config)
+        limit: Maximum number of articles to return (defaults to global_news_article_limit config)
 
     Returns:
         Formatted string containing global news articles
     """
+    config = get_config()
+    if look_back_days is None:
+        look_back_days = config.get("global_news_lookback_days", 7)
+    if limit is None:
+        limit = config.get("global_news_article_limit", 10)
     # Search queries for macro/global news
     search_queries = [
         "stock market economy",

tradingagents/default_config.py

@@ -22,6 +22,10 @@ DEFAULT_CONFIG = {
     "max_debate_rounds": 1,
     "max_risk_discuss_rounds": 1,
     "max_recur_limit": 100,
+    # News fetching configuration
+    "news_article_limit": 20,           # max articles per ticker for get_news
+    "global_news_lookback_days": 7,     # lookback window (days) for get_global_news
+    "global_news_article_limit": 10,    # max articles returned by get_global_news
     # Data vendor configuration
     # Category-level configuration (default for all tools in category)
     "data_vendors": {