[PROBLEM] codex mcp doesn't start codex CLI as an MCP server #2208
Description
File to be fixed
The issue is in https://github.com/openai/openai-cookbook/blob/main/examples/codex/codex_mcp_agents_sdk/building_consistent_workflows_codex_cli_agents_sdk.ipynb
The problem
The MCPServerStdio object is instantiated with args=["-y", "codex", "mcp"]
This produced a help verbose for the codex mcp command as if I started codex CLI in the terminal and then gave it the /mcp directive. And then the Codex MCP server in the example cookbook, that was supposed to run and receive commands through stdio, close connection at initialization.
Solution
As described in here https://github.com/openai/codex/blob/main/docs/advanced.md#model-context-protocol-mcp the command is supposed to be codex mcp-server NOT codex mcp.
So, adding "-server" to the "mcp" argument fixed it for me.
Additional context
The error thrown:
Error initializing MCP server: Connection closed
Traceback (most recent call last):
File ".../mcp_server.py", line 22, in <module>
asyncio.run(main())
File ".../my_env/lib/python3.10/asyncio/runners.py", line 44, in run
return loop.run_until_complete(main)
File ".../my_env/lib/python3.10/asyncio/base_events.py", line 649, in run_until_complete
return future.result()
File ".../mcp_server.py", line 8, in main
async with MCPServerStdio(
File ".../my_env/lib/python3.10/site-packages/agents/mcp/server.py", line 242, in __aenter__
await self.connect()
File ".../my_env/lib/python3.10/site-packages/agents/mcp/server.py", line 283, in connect
server_result = await session.initialize()
File ".../my_env/lib/python3.10/site-packages/mcp/client/session.py", line 152, in initialize
result = await self.send_request(
File ".../my_env/lib/python3.10/site-packages/mcp/shared/session.py", line 286, in send_request
raise McpError(response_or_error.error)
mcp.shared.exceptions.McpError: Connection closed
My system:
Linux: Ubuntu 20.04.6 LTS
Node version v22.21.0
codex-cli version 0.50.0
My environment Packages:
# packages in environment:
#
# Name Version Build Channel
_libgcc_mutex 0.1 conda_forge conda-forge
_openmp_mutex 4.5 2_gnu conda-forge
aiofiles 25.1.0 pypi_0 pypi
aiohappyeyeballs 2.6.1 pypi_0 pypi
aiohttp 3.13.1 pypi_0 pypi
aiosignal 1.4.0 pypi_0 pypi
annotated-types 0.7.0 pypi_0 pypi
anyio 4.11.0 pypi_0 pypi
async-timeout 5.0.1 pypi_0 pypi
attrs 25.4.0 pypi_0 pypi
av 15.1.0 pypi_0 pypi
bzip2 1.0.8 hda65f42_8 conda-forge
ca-certificates 2025.10.5 hbd8a1cb_0 conda-forge
certifi 2025.10.5 pypi_0 pypi
cffi 2.0.0 pypi_0 pypi
charset-normalizer 3.4.4 pypi_0 pypi
click 8.3.0 pypi_0 pypi
colorama 0.4.6 pypi_0 pypi
coloredlogs 15.0.1 pypi_0 pypi
distro 1.9.0 pypi_0 pypi
docstring-parser 0.17.0 pypi_0 pypi
dotenv 0.9.9 pypi_0 pypi
eval-type-backport 0.2.2 pypi_0 pypi
exceptiongroup 1.3.0 pypi_0 pypi
filelock 3.20.0 pypi_0 pypi
flatbuffers 25.9.23 pypi_0 pypi
frozenlist 1.8.0 pypi_0 pypi
fsspec 2025.9.0 pypi_0 pypi
gitdb 4.0.12 pypi_0 pypi
gitpython 3.1.45 pypi_0 pypi
googleapis-common-protos 1.71.0 pypi_0 pypi
griffe 1.14.0 pypi_0 pypi
grpcio 1.76.0 pypi_0 pypi
h11 0.16.0 pypi_0 pypi
hf-xet 1.2.0 pypi_0 pypi
httpcore 1.0.9 pypi_0 pypi
httpx 0.28.1 pypi_0 pypi
httpx-sse 0.4.3 pypi_0 pypi
huggingface-hub 0.36.0 pypi_0 pypi
humanfriendly 10.0 pypi_0 pypi
idna 3.11 pypi_0 pypi
importlib-metadata 8.7.0 pypi_0 pypi
iniconfig 2.3.0 pypi_0 pypi
jinja2 3.1.6 pypi_0 pypi
jiter 0.11.1 pypi_0 pypi
jsonschema 4.25.1 pypi_0 pypi
jsonschema-specifications 2025.9.1 pypi_0 pypi
ld_impl_linux-64 2.44 h1aa0949_4 conda-forge
libexpat 2.7.1 hecca717_0 conda-forge
libffi 3.5.2 h9ec8514_0 conda-forge
libgcc 15.2.0 h767d61c_7 conda-forge
libgcc-ng 15.2.0 h69a702a_7 conda-forge
libgomp 15.2.0 h767d61c_7 conda-forge
liblzma 5.8.1 hb9d3cd8_2 conda-forge
libnsl 2.0.1 hb9d3cd8_1 conda-forge
libsqlite 3.50.4 h0c1763c_0 conda-forge
libstdcxx 15.2.0 h8f9b012_7 conda-forge
libuuid 2.41.2 he9a06e4_0 conda-forge
libxcrypt 4.4.36 hd590300_1 conda-forge
libzlib 1.3.1 hb9d3cd8_2 conda-forge
livekit 1.0.17 pypi_0 pypi
livekit-agents 1.2.15 pypi_0 pypi
livekit-api 1.0.7 pypi_0 pypi
livekit-blingfire 1.0.0 pypi_0 pypi
livekit-plugins-noise-cancellation 0.2.5 pypi_0 pypi
livekit-plugins-openai 1.2.15 pypi_0 pypi
livekit-plugins-silero 1.2.15 pypi_0 pypi
livekit-plugins-turn-detector 1.2.15 pypi_0 pypi
livekit-protocol 1.0.8 pypi_0 pypi
markupsafe 3.0.3 pypi_0 pypi
mcp 1.19.0 pypi_0 pypi
mpmath 1.3.0 pypi_0 pypi
multidict 6.7.0 pypi_0 pypi
ncurses 6.5 h2d0b736_3 conda-forge
nest-asyncio 1.6.0 pypi_0 pypi
numpy 2.2.6 pypi_0 pypi
onnxruntime 1.23.2 pypi_0 pypi
openai 2.6.1 pypi_0 pypi
openai-agents 0.4.2 pypi_0 pypi
openssl 3.5.4 h26f9b46_0 conda-forge
opentelemetry-api 1.38.0 pypi_0 pypi
opentelemetry-exporter-otlp 1.38.0 pypi_0 pypi
opentelemetry-exporter-otlp-proto-common 1.38.0 pypi_0 pypi
opentelemetry-exporter-otlp-proto-grpc 1.38.0 pypi_0 pypi
opentelemetry-exporter-otlp-proto-http 1.38.0 pypi_0 pypi
opentelemetry-proto 1.38.0 pypi_0 pypi
opentelemetry-sdk 1.38.0 pypi_0 pypi
opentelemetry-semantic-conventions 0.59b0 pypi_0 pypi
packaging 25.0 pypi_0 pypi
pillow 12.0.0 pypi_0 pypi
pip 25.2 pyh8b19718_0 conda-forge
pluggy 1.6.0 pypi_0 pypi
prometheus-client 0.23.1 pypi_0 pypi
propcache 0.4.1 pypi_0 pypi
protobuf 6.33.0 pypi_0 pypi
psutil 7.1.2 pypi_0 pypi
pycparser 2.23 pypi_0 pypi
pydantic 2.12.3 pypi_0 pypi
pydantic-core 2.41.4 pypi_0 pypi
pydantic-settings 2.11.0 pypi_0 pypi
pygments 2.19.2 pypi_0 pypi
pyjwt 2.10.1 pypi_0 pypi
pytest 8.4.2 pypi_0 pypi
python 3.10.19 h3c07f61_2_cpython conda-forge
python-dotenv 1.2.1 pypi_0 pypi
python-multipart 0.0.20 pypi_0 pypi
pyyaml 6.0.3 pypi_0 pypi
readline 8.2 h8c095d6_2 conda-forge
referencing 0.37.0 pypi_0 pypi
regex 2025.10.23 pypi_0 pypi
requests 2.32.5 pypi_0 pypi
rpds-py 0.28.0 pypi_0 pypi
safetensors 0.6.2 pypi_0 pypi
setuptools 80.9.0 pyhff2d567_0 conda-forge
smmap 5.0.2 pypi_0 pypi
sniffio 1.3.1 pypi_0 pypi
sounddevice 0.5.3 pypi_0 pypi
sse-starlette 3.0.2 pypi_0 pypi
starlette 0.48.0 pypi_0 pypi
sympy 1.14.0 pypi_0 pypi
tk 8.6.13 noxft_hd72426e_102 conda-forge
tokenizers 0.22.1 pypi_0 pypi
tomli 2.3.0 pypi_0 pypi
tqdm 4.67.1 pypi_0 pypi
transformers 4.57.1 pypi_0 pypi
types-protobuf 6.32.1.20250918 pypi_0 pypi
types-requests 2.32.4.20250913 pypi_0 pypi
typing-extensions 4.15.0 pypi_0 pypi
typing-inspection 0.4.2 pypi_0 pypi
tzdata 2025b h78e105d_0 conda-forge
urllib3 2.5.0 pypi_0 pypi
uvicorn 0.38.0 pypi_0 pypi
watchfiles 1.1.1 pypi_0 pypi
websockets 15.0.1 pypi_0 pypi
wheel 0.45.1 pyhd8ed1ab_1 conda-forge
yarl 1.22.0 pypi_0 pypi
zipp 3.23.0 pypi_0 pypi
zstd 1.5.7 hb8e6e7a_2 conda-forge