changed README, added minimal_mcp_server

ai/gen-ai-agents/custom-rag-agent/README.md

@@ -3,7 +3,9 @@ This repository contains the code for the development of a **custom RAG Agent**,
 
 **Author**: L. Saetta
 
-**Last updated**: 11/09/2025
+**Reviewed**: 23.09.2025
+
+![UI](images/ui_image.png)
 
 ## Design and implementation
 * The agent is implemented using **LangGraph**

ai/gen-ai-agents/custom-rag-agent/llm_with_mcp.py

@@ -102,7 +102,7 @@ async def _list_tools(self):
         Fetch tools from the MCP server using FastMCP. Must be async.
         """
         jwt = self.jwt_supplier()
-        
+
         logger.info("Listing tools from %s ...", self.mcp_url)
 
         # FastMCP requires async context + await for client ops.

ai/gen-ai-agents/custom-rag-agent/minimal_mcp_server.py

@@ -0,0 +1,88 @@
+"""
+Minimal-but-solid MCP server with JWT hardening and sane defaults.
+
+- Safe defaults for transports
+"""
+
+from fastmcp import FastMCP
+
+# to verify the JWT token
+# if you don't need to add security, you can remove this
+# in newer version of FastMCP should be replaced with
+# from fastmcp.server.auth.providers.jwt import JWTVerifier
+from fastmcp.server.auth import BearerAuthProvider
+
+from config import (
+    # first four needed only to manage JWT
+    ENABLE_JWT_TOKEN,
+    IAM_BASE_URL,
+    ISSUER,
+    AUDIENCE,
+    TRANSPORT,
+    # needed only if transport is stremable-http
+    HOST,
+    PORT,
+)
+
+
+#
+# if you don't need to add security, you can remove this part and set
+# AUTH = None, simply set ENABLE_JWT_TOKEN = False
+#
+AUTH = None
+
+if ENABLE_JWT_TOKEN:
+    # check that a valid JWT token is provided
+    AUTH = BearerAuthProvider(
+        # this is the url to get the public key from IAM
+        # the PK is used to check the JWT
+        jwks_uri=f"{IAM_BASE_URL}/admin/v1/SigningCert/jwk",
+        issuer=ISSUER,
+        audience=AUDIENCE,
+    )
+
+#
+# define the MCP server
+#
+mcp = FastMCP("MCP server with few lines of code, but secure", auth=AUTH)
+
+
+#
+# MCP tools definition
+# add and write the code for the tools here
+#
+@mcp.tool
+def say_the_truth(user: str) -> str:
+    """
+    This tool, given the name of the user return one of the secret truths.
+
+    Args:
+        user: The caller's display name or identifier.
+
+    Returns:
+        A short truth string. 
+    """
+    # here you'll put the code that reads and return the info requested
+    # mark each tool with the annotation
+    return f"{user}: Less is more!"
+
+
+#
+# Run the MCP server
+#
+if __name__ == "__main__":
+    # Validate transport
+    if TRANSPORT not in {"stdio", "streamable-http"}:
+        # don't use sse! it is deprecated!
+        raise RuntimeError(f"Unsupported TRANSPORT: {TRANSPORT}")
+
+    if TRANSPORT == "stdio":
+        # stdio doesn’t support host/port args
+        mcp.run(transport=TRANSPORT)
+    else:
+        # For http/streamable-http transport, host/port are valid
+        mcp.run(
+            transport=TRANSPORT,
+            host=HOST,
+            port=PORT,
+        )

ai/gen-ai-agents/custom-rag-agent/ui_mcp_agent.py

@@ -3,11 +3,15 @@
 """
 
 import asyncio
+import traceback
 import streamlit as st
 from mcp_servers_config import MCP_SERVERS_CONFIG
 
 # this one contains the backend and the test code only for console
 from llm_with_mcp import AgentWithMCP, default_jwt_supplier
+from utils import get_console_logger
+
+logger = get_console_logger()
 
 # ---------- Page setup ----------
 st.set_page_config(page_title="MCP UI", page_icon="🛠️", layout="wide")
@@ -50,6 +54,9 @@
         except Exception as e:
             st.session_state.agent = None
             st.error(f"Failed to connect: {e}")
+            logger.error(e)
+            stack_str = traceback.format_exc()
+            logger.error(stack_str)
 
 # ---------- Chat history (display) ----------
 for msg in st.session_state.chat: