Add lifespan property to app

docs/deployment/asgi.mdx

@@ -124,7 +124,7 @@ app = Starlette(
         Mount("/mcp-server", app=mcp_app),
         # Add other routes as needed
     ],
-    lifespan=mcp_app.router.lifespan_context,
+    lifespan=mcp_app.lifespan,
 )
 ```
 
@@ -154,7 +154,7 @@ mcp_app = mcp.http_app(path='/mcp')
 inner_app = Starlette(routes=[Mount("/inner", app=mcp_app)])
 app = Starlette(
     routes=[Mount("/outer", app=inner_app)],
-    lifespan=mcp_app.router.lifespan_context,
+    lifespan=mcp_app.lifespan,
 )
 ```
 
@@ -181,7 +181,7 @@ mcp = FastMCP("MyServer")
 mcp_app = mcp.http_app(path='/mcp')
 
 # Create a FastAPI app and mount the MCP server
-app = FastAPI(lifespan=mcp_app.router.lifespan_context)
+app = FastAPI(lifespan=mcp_app.lifespan)
 app.mount("/mcp-server", mcp_app)
 ```
 

src/fastmcp/server/http.py

@@ -27,7 +27,7 @@ from starlette.middleware.authentication import AuthenticationMiddleware
 from starlette.requests import Request
 from starlette.responses import Response
 from starlette.routing import BaseRoute, Mount, Route
-from starlette.types import Receive, Scope, Send
+from starlette.types import Lifespan, Receive, Scope, Send
 
 from fastmcp.utilities.logging import get_logger
 
@@ -43,6 +43,12 @@ _current_http_request: ContextVar[Request | None] = ContextVar(
 )
 
 
+class StarletteWithLifespan(Starlette):
+    @property
+    def lifespan(self) -> Lifespan:
+        return self.router.lifespan_context
+
+
 @contextmanager
 def set_http_request(request: Request) -> Generator[Request, None, None]:
     token = _current_http_request.set(request)
@@ -122,7 +128,7 @@ def create_base_app(
     middleware: list[Middleware],
     debug: bool = False,
     lifespan: Callable | None = None,
-) -> Starlette:
+) -> StarletteWithLifespan:
     """Create a base Starlette app with common middleware and routes.
 
     Args:
@@ -137,7 +143,7 @@ def create_base_app(
     # Always add RequestContextMiddleware as the outermost middleware
     middleware.append(Middleware(RequestContextMiddleware))
 
-    return Starlette(
+    return StarletteWithLifespan(
         routes=routes,
         middleware=middleware,
         debug=debug,
@@ -157,7 +163,7 @@ def create_sse_app(
     debug: bool = False,
     routes: list[BaseRoute] | None = None,
     middleware: list[Middleware] | None = None,
-) -> Starlette:
+) -> StarletteWithLifespan:
     """Return an instance of the SSE server app.
 
     Args:
@@ -262,7 +268,7 @@ def create_streamable_http_app(
     debug: bool = False,
     routes: list[BaseRoute] | None = None,
     middleware: list[Middleware] | None = None,
-) -> Starlette:
+) -> StarletteWithLifespan:
     """Return an instance of the StreamableHTTP server app.
 
     Args:

src/fastmcp/server/server.py

@@ -35,7 +35,6 @@ from mcp.types import Resource as MCPResource
 from mcp.types import ResourceTemplate as MCPResourceTemplate
 from mcp.types import Tool as MCPTool
 from pydantic import AnyUrl
-from starlette.applications import Starlette
 from starlette.middleware import Middleware
 from starlette.requests import Request
 from starlette.responses import Response
@@ -48,7 +47,11 @@ from fastmcp.prompts import Prompt, PromptManager
 from fastmcp.prompts.prompt import PromptResult
 from fastmcp.resources import Resource, ResourceManager
 from fastmcp.resources.template import ResourceTemplate
-from fastmcp.server.http import create_sse_app
+from fastmcp.server.http import (
+    StarletteWithLifespan,
+    create_sse_app,
+    create_streamable_http_app,
+)
 from fastmcp.tools import ToolManager
 from fastmcp.tools.tool import Tool
 from fastmcp.utilities.cache import TimedCache
@@ -59,7 +62,6 @@ if TYPE_CHECKING:
     from fastmcp.client import Client
     from fastmcp.server.openapi import FastMCPOpenAPI
     from fastmcp.server.proxy import FastMCPProxy
-
 logger = get_logger(__name__)
 
 DuplicateBehavior = Literal["warn", "error", "replace", "ignore"]
@@ -806,7 +808,7 @@ class FastMCP(Generic[LifespanResultT]):
         path: str | None = None,
         message_path: str | None = None,
         middleware: list[Middleware] | None = None,
-    ) -> Starlette:
+    ) -> StarletteWithLifespan:
         """
         Create a Starlette app for the SSE server.
 
@@ -837,7 +839,7 @@ class FastMCP(Generic[LifespanResultT]):
         self,
         path: str | None = None,
         middleware: list[Middleware] | None = None,
-    ) -> Starlette:
+    ) -> StarletteWithLifespan:
         """
         Create a Starlette app for the StreamableHTTP server.
 
@@ -858,7 +860,7 @@ class FastMCP(Generic[LifespanResultT]):
         path: str | None = None,
         middleware: list[Middleware] | None = None,
         transport: Literal["streamable-http", "sse"] = "streamable-http",
-    ) -> Starlette:
+    ) -> StarletteWithLifespan:
         """Create a Starlette app using the specified HTTP transport.
 
         Args:
@@ -869,7 +871,6 @@ class FastMCP(Generic[LifespanResultT]):
         Returns:
             A Starlette application configured with the specified transport
         """
-        from fastmcp.server.http import create_streamable_http_app
 
         if transport == "streamable-http":
             return create_streamable_http_app(

tests/client/test_streamable_http.py

@@ -119,7 +119,7 @@ def run_nested_server(host: str, port: int) -> None:
         mount = Starlette(routes=[Mount("/nest-inner", app=mcp_app)])
         mount2 = Starlette(
             routes=[Mount("/nest-outer", app=mount)],
-            lifespan=mcp_app.router.lifespan_context,
+            lifespan=mcp_app.lifespan,
         )
         server = uvicorn.Server(
             config=uvicorn.Config(