fix: cache query to avoid LangGraph sandbox issues

Signed-off-by: Tyler Slaton <tyler@copilotkit.ai>

Author: tylerslaton

apps/agent/src/query.py

@@ -2,12 +2,15 @@
 from pathlib import Path
 import csv
 
+# Read data at module load time to avoid file I/O issues in
+# LangGraph Cloud's sandboxed tool execution environment.
+_csv_path = Path(__file__).parent / "db.csv"
+with open(_csv_path) as _f:
+    _cached_data = list(csv.DictReader(_f))
+
 @tool
 def query_data(query: str):
     """
     Query the database, takes natural language. Always call before showing a chart or graph.
     """
-    csv_path = Path(__file__).parent / "db.csv"
-    with open(csv_path) as f:
-        reader = csv.DictReader(f)
-        return list(reader)
+    return _cached_data