chore: import upstream snapshot with attribution

examples/snippets/servers/streamable_http_host_mounting.py

@@ -0,0 +1,38 @@
+"""Example showing how to mount StreamableHTTP server using Host-based routing.
+
+Run from the repository root:
+    uvicorn examples.snippets.servers.streamable_http_host_mounting:app --reload
+"""
+
+import contextlib
+
+from starlette.applications import Starlette
+from starlette.routing import Host
+
+from mcp.server.mcpserver import MCPServer
+
+# Create MCP server
+mcp = MCPServer("MCP Host App")
+
+
+@mcp.tool()
+def domain_info() -> str:
+    """Get domain-specific information"""
+    return "This is served from mcp.acme.corp"
+
+
+# Create a lifespan context manager to run the session manager
+@contextlib.asynccontextmanager
+async def lifespan(app: Starlette):
+    async with mcp.session_manager.run():
+        yield
+
+
+# Mount using Host-based routing
+# Transport-specific options are passed to streamable_http_app()
+app = Starlette(
+    routes=[
+        Host("mcp.acme.corp", app=mcp.streamable_http_app(json_response=True)),
+    ],
+    lifespan=lifespan,
+)