Update mcp_server.py

mcp_server.py

@@ -1,43 +1,48 @@
 from mcp.server.fastmcp import FastMCP
 import sqlite3, json
 
+# ─── MCP instance ───────────────────────────────────────────────────────
 mcp = FastMCP("EnterpriseData")
 
-# In-memory SQLite
+# ─── In-memory SQLite sample DB ─────────────────────────────────────────
 conn = sqlite3.connect(":memory:", check_same_thread=False)
-cur = conn.cursor()
+cur  = conn.cursor()
 
 cur.execute("""
-CREATE TABLE Customers(
-    CustomerID INTEGER PRIMARY KEY AUTOINCREMENT,
-    Name TEXT,
-    Region TEXT,
-    LastOrderDate TEXT
+CREATE TABLE Customers (
+    CustomerID      INTEGER PRIMARY KEY AUTOINCREMENT,
+    Name            TEXT,
+    Region          TEXT,
+    LastOrderDate   TEXT
 )
 """)
 
 cur.executemany(
     "INSERT INTO Customers (Name, Region, LastOrderDate) VALUES (?,?,?)",
     [
-        ("Acme Corp", "Northeast", "2024-12-01"),
-        ("Beta Inc", "West",      "2025-06-01"),
-        ("Gamma Co", "Northeast", "2023-09-15"),
-        ("Delta LLC", "South",    "2025-03-20"),
-        ("Epsilon Ltd", "Northeast","2025-07-10"),
+        ("Acme Corp",  "Northeast", "2024-12-01"),
+        ("Beta Inc",   "West",      "2025-06-01"),
+        ("Gamma Co",   "Northeast", "2023-09-15"),
+        ("Delta LLC",  "South",     "2025-03-20"),
+        ("Epsilon Ltd","Northeast", "2025-07-10"),
     ]
 )
 conn.commit()
 
+# ─── SQL tool exposed to the agent ──────────────────────────────────────
 @mcp.tool()
 def query_database(sql: str) -> str:
-    """Run SQL and return JSON rows."""
+    """
+    Execute raw SQL and return rows as JSON.
+    Example:  SELECT * FROM Customers WHERE Region='West';
+    """
     try:
         cur.execute(sql)
         cols = [d[0] for d in cur.description or []]
         rows = [dict(zip(cols, r)) for r in cur.fetchall()]
         return json.dumps(rows)
-    except Exception as e:
-        return json.dumps({"error": str(e)})
+    except Exception as exc:
+        return json.dumps({"error": str(exc)})
 
 if __name__ == "__main__":
     mcp.run(transport="stdio")