fix(samples): accept explicit null for optional MCP params, keep logs off stdout

python/04-industry-use-cases/finance/genai-powered-financial-advisor-tools/application/mcp_server_kb.py

@@ -5,7 +5,7 @@
 import logging
 import os
 import sys
-from typing import Any, Dict, List
+from typing import Any, Dict, List, Optional
 from pathlib import Path
 import yaml
 
@@ -51,7 +51,7 @@ def load_config():
     logger.error(f"{err_msg}")
 
 @mcp.tool()
-async def knowledge_base_list(region_name: str = None) -> List[Dict[str, Any]]:
+async def knowledge_base_list(region_name: Optional[str] = None) -> List[Dict[str, Any]]:
     """Extract the list of Knowledge Bases on Amazon Bedrock
 
     Args:

python/04-industry-use-cases/finance/genai-powered-financial-advisor-tools/application/mcp_server_stock.py

@@ -402,7 +402,7 @@ async def create_comparison_chart(tickers: str, period: Optional[str] = None) ->
         timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
         filename = f"comparison_{'_'.join(ticker_list)}_{period or '1y'}_{timestamp}.png"
         filepath = os.path.join("outputs/charts/", filename)
-        print(f"\nfilepath: {filepath}")
+        print(f"\nfilepath: {filepath}", file=sys.stderr)
 
         plt.savefig(filepath, dpi=300, bbox_inches='tight')
         plt.close()

python/07-ux-demos/triage-agent/backend/mcp_servers/email_history/email_history_server.py

@@ -1,7 +1,7 @@
 from mcp.server import FastMCP
 import json
 import os
-from typing import List, Dict
+from typing import List, Dict, Optional
 
 # Create a new MCP server
 mcp = FastMCP("Email History Server")
@@ -19,7 +19,7 @@ def load_emails() -> List[Dict]:
 @mcp.tool(description="Get sent emails with optional filtering")
 def get_emails(
     limit: int = 10,
-    subject_contains: str = None
+    subject_contains: Optional[str] = None
 ) -> List[Dict]:
     """Get sent emails with optional filtering."""
     emails = load_emails()

python/07-ux-demos/triage-agent/backend/mcp_servers/strands/strands_agent.py

@@ -1,3 +1,4 @@
+import sys
 from mcp.server import FastMCP
 from strands import Agent
 from strands_tools import http_request
@@ -23,7 +24,7 @@ def real_estate_agent(query: str) -> str:
     formatted_query = f"Answer the following question: {query}"
 
     try:
-        print("Routed to Real Estate Expert")
+        print("Routed to Real Estate Expert", file=sys.stderr)
         real_estate_agent = Agent(
             model="us.amazon.nova-pro-v1:0",
             system_prompt=REAL_ESTATE_SYSTEM_PROMPT,