Update app.py

app.py

@@ -4,17 +4,20 @@ from fastapi import FastAPI, HTTPException
 from fastapi.middleware.cors import CORSMiddleware
 from pydantic import BaseModel
 
+# -------------------------------------------------
+# FastAPI App Configuration
+# -------------------------------------------------
 app = FastAPI(
     title="SAP Purchase Order API Demo",
     description=(
-        "Fetches purchase order data from SAP Sandbox API.\n\n"
+        "Backend to fetch purchase order data from SAP Sandbox API.\n\n"
         "Designed for integration with OpenAI Agentkit UI — "
-        "Agentkit auto-discovers endpoints from `/openapi.json`."
+        "Agentkit automatically discovers endpoints from `/openapi.json`."
     ),
     version="1.0.0",
 )
 
-# Allow all origins for Agentkit / external calls
+# Enable CORS for Agentkit and browser testing
 app.add_middleware(
     CORSMiddleware,
     allow_origins=["*"],
@@ -23,15 +26,18 @@ app.add_middleware(
     allow_headers=["*"],
 )
 
-# Read secret from Hugging Face environment
+# -------------------------------------------------
+# Environment Variables
+# -------------------------------------------------
 SAP_API_KEY = os.getenv("SAP_API_KEY")
 SAP_BASE_URL = (
     "https://sandbox.api.sap.com/s4hanacloud/sap/opu/odata4/"
     "sap/api_purchaseorder_2/srvd_a2x/sap/purchaseorder/0001/PurchaseOrder?$top=50"
 )
 
-# --- Models ---
-
+# -------------------------------------------------
+# Pydantic Models (for OpenAPI schema)
+# -------------------------------------------------
 class PurchaseOrderItem(BaseModel):
     PurchaseOrder: str | None = None
     Supplier: str | None = None
@@ -45,11 +51,30 @@ class PurchaseOrderResponse(BaseModel):
     data: list[PurchaseOrderItem] | dict
 
 
-# --- Routes ---
+# -------------------------------------------------
+# Routes
+# -------------------------------------------------
+
+@app.get("/", tags=["Root"])
+async def root():
+    """Friendly welcome message for the root URL."""
+    return {
+        "message": "👋 Welcome to the SAP Purchase Order API demo!",
+        "available_endpoints": {
+            "health": "/health",
+            "purchase_orders": "/purchase-orders",
+            "docs": "/docs"
+        },
+        "instructions": (
+            "Use /purchase-orders to fetch SAP Sandbox data, "
+            "or open /docs for the interactive Swagger UI."
+        ),
+    }
+
 
 @app.get("/health", summary="Health check", tags=["System"])
 async def health_check():
-    """Simple endpoint to verify the backend is running."""
+    """Check if the API is running."""
     return {"status": "ok", "message": "SAP Purchase Order API backend is running"}
 
 
@@ -58,10 +83,10 @@ async def health_check():
     response_model=PurchaseOrderResponse,
     summary="Get Purchase Orders",
     tags=["Purchase Orders"],
-    description="Fetch top 50 purchase orders from SAP Sandbox API.",
+    description="Fetches the top 50 purchase orders from the SAP Sandbox API.",
 )
 async def get_purchase_orders():
-    """Fetches purchase orders from SAP Sandbox API"""
+    """Fetch purchase order data from SAP Sandbox API."""
     if not SAP_API_KEY:
         raise HTTPException(status_code=500, detail="SAP_API_KEY not found in environment")