docs: clarify streamable_http_path configuration when mounting servers (#1172)

examples/snippets/servers/streamable_http_path_config.py

@@ -0,0 +1,29 @@
+"""
+Example showing path configuration during FastMCP initialization.
+
+Run from the repository root:
+    uvicorn examples.snippets.servers.streamable_http_path_config:app --reload
+"""
+
+from starlette.applications import Starlette
+from starlette.routing import Mount
+
+from mcp.server.fastmcp import FastMCP
+
+# Configure streamable_http_path during initialization
+# This server will mount at the root of wherever it's mounted
+mcp_at_root = FastMCP("My Server", streamable_http_path="/")
+
+
+@mcp_at_root.tool()
+def process_data(data: str) -> str:
+    """Process some data"""
+    return f"Processed: {data}"
+
+
+# Mount at /process - endpoints will be at /process instead of /process/mcp
+app = Starlette(
+    routes=[
+        Mount("/process", app=mcp_at_root.streamable_http_app()),
+    ]
+)