Markitdown-mcp 0.0.1a4 raise TypeError: 'NoneType' object is not callable

Env:
Use tag:0.1.2 version.
markitdown 0.1.2
markitdown-mcp 0.0.1a4

CLI:

markitdown-mcp --sse --host 0.0.0.0 --port 11426

ERROR:

INFO:     172.17.0.1:59658 - "GET /sse HTTP/1.1" 200 OK
INFO:     172.17.0.1:59666 - "POST /messages/?session_id=1ae35d0d71cf442d913f90dfddbc1082 HTTP/1.1" 202 Accepted
INFO:     172.17.0.1:59672 - "POST /messages/?session_id=1ae35d0d71cf442d913f90dfddbc1082 HTTP/1.1" 202 Accepted
INFO:     172.17.0.1:59688 - "POST /messages/?session_id=1ae35d0d71cf442d913f90dfddbc1082 HTTP/1.1" 202 Accepted
Processing request of type ListToolsRequest
ERROR:    Exception in ASGI application
Traceback (most recent call last):
  File "/usr/local/lib/python3.13/site-packages/uvicorn/protocols/http/h11_impl.py", line 403, in run_asgi
    result = await app(  # type: ignore[func-returns-value]
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        self.scope, self.receive, self.send
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/usr/local/lib/python3.13/site-packages/uvicorn/middleware/proxy_headers.py", line 60, in __call__
    return await self.app(scope, receive, send)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.13/site-packages/starlette/applications.py", line 113, in __call__
    await self.middleware_stack(scope, receive, send)
  File "/usr/local/lib/python3.13/site-packages/starlette/middleware/errors.py", line 186, in __call__
    raise exc
  File "/usr/local/lib/python3.13/site-packages/starlette/middleware/errors.py", line 164, in __call__
    await self.app(scope, receive, _send)
  File "/usr/local/lib/python3.13/site-packages/starlette/middleware/exceptions.py", line 63, in __call__
    await wrap_app_handling_exceptions(self.app, conn)(scope, receive, send)
  File "/usr/local/lib/python3.13/site-packages/starlette/_exception_handler.py", line 53, in wrapped_app
    raise exc
  File "/usr/local/lib/python3.13/site-packages/starlette/_exception_handler.py", line 42, in wrapped_app
    await app(scope, receive, sender)
  File "/usr/local/lib/python3.13/site-packages/starlette/routing.py", line 716, in __call__
    await self.middleware_stack(scope, receive, send)
  File "/usr/local/lib/python3.13/site-packages/starlette/routing.py", line 736, in app
    await route.handle(scope, receive, send)
  File "/usr/local/lib/python3.13/site-packages/starlette/routing.py", line 290, in handle
    await self.app(scope, receive, send)
  File "/usr/local/lib/python3.13/site-packages/starlette/routing.py", line 78, in app
    await wrap_app_handling_exceptions(app, request)(scope, receive, send)
  File "/usr/local/lib/python3.13/site-packages/starlette/_exception_handler.py", line 53, in wrapped_app
    raise exc
  File "/usr/local/lib/python3.13/site-packages/starlette/_exception_handler.py", line 42, in wrapped_app
    await app(scope, receive, sender)
  File "/usr/local/lib/python3.13/site-packages/starlette/routing.py", line 76, in app
    await response(scope, receive, send)
          ~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^
TypeError: 'NoneType' object is not callable

Reproduce the failure with markitdown-mcp --sse --host 0.0.0.0 --port 11426, then inspect the SSE request handling around the logged ListToolsRequest and the ASGI traceback. Done means listing tools through the SSE endpoint completes without the NoneType callable error.