MCP servers are not working on windows

Resolved 💬 17 comments Opened Sep 12, 2025 by T1nker-1220 Closed Nov 26, 2025

💡 Likely answer: A maintainer (etraut-openai, contributor) responded on this thread — see the highlighted reply below.

What version of Codex is running?

codex-cli 0.31.0

Which model were you using?

gpt5

What platform is your computer?

windows 11 pro

What steps can reproduce the bug?

the npx is not working

tool running...
firebase-afterdark.firebase_query({"target":"firestore","operation":"list_collections","params":{}})
                                                                                                                       
tool failed, duration: 1m20s                                                                                           
firebase-afterdark.firebase_query({"target":"firestore","operation":"list_collections","params":{}})                   
Error: tool call error: tool call failed for `firebase-afterdark/firebase_query` 

tool running...
context7.resolve-library-id({"libraryName":"Next.js 14.1.1"})

tool success, duration: 3ms
context7.resolve-library-id({"libraryName":"Next.js 14.1.1"})

Error searching libraries: TypeError: fetch failed

> Network is still restricted, so Context7 lookups are failing.

[mcp_servers.context7]
command = "node"
args = ["C:/Users/NATH/Documents/Cline/MCP/context7/dist/index.js"]
type = "stdio"

[mcp_servers.playwright]
command = "node"
args = ["C:/Users/NATH/Documents/Cline/MCP/playwright-mcp/lib/index.js"]
type = "stdio"

What is the expected behavior?

_No response_

What do you see instead?

_No response_

Additional information

_No response_

View original on GitHub ↗

17 Comments

AyinMostima · 10 months ago

There's a good way to do this: check the configuration paths for your commands. This way, you can configure multiple MCPs for uv, uvx, and npx. Here are some examples:
[mcp_servers.context7]
type = "stdio"
command = 'C:\\Program Files\\nodejs\\npx.cmd'
args = ["-y", "@upstash/context7-mcp@latest"]
env = { APPDATA = 'C:\\Users\\lenovo\\AppData\\Roaming', LOCALAPPDATA = 'C:\\Users\\lenovo\\AppData\\Local', HOME = 'C:\\Users\\lenovo', SystemRoot = 'C:\\Windows' }
startup_timeout_ms = 20_000

[mcp_servers."perplexity-mcp"]
type = "stdio"
command = 'C:\Users\lenovo\.local\bin\uvx.exe'
args = ["perplexity-mcp"]
env = { PERPLEXITY_API_KEY = "XXXXXXX", PERPLEXITY_MODEL = "sonar", APPDATA = 'C:\\Users\\lenovo\\AppData\\Roaming', LOCALAPPDATA = 'C:\\Users\\lenovo\\AppData\\Local', HOME = 'C:\\Users\\lenovo', SystemRoot = 'C:\\Windows' }

[mcp_servers.serena]
type = "stdio"
command = 'C:\\Users\\lenovo\\.local\\bin\\uv.exe'
args = ["run", "--directory", "F:\\Homework\\MyMCP\\serena", "serena-mcp-server"]
env = { APPDATA = 'C:\\Users\\lenovo\\AppData\\Roaming', LOCALAPPDATA = 'C:\\Users\\lenovo\\AppData\\Local', HOME = 'C:\\Users\\lenovo', SystemRoot = 'C:\\Windows' }
startup_timeout_ms = 20_000

AyinMostima · 10 months ago

Of course, if you are sse please use this uv tool install mcp-proxy, here is an example:
[mcp_servers."graphiti-memory-stdio-via-proxy"]
type = "stdio"
command = 'C:\\Users\\lenovo\\.local\\bin\\uvx.exe'
args = ["mcp-proxy", "http://127.0.0.1:15627/sse"]
env = { APPDATA = 'C:\\Users\\lenovo\\AppData\\Roaming', LOCALAPPDATA = 'C:\\Users\\lenovo\\AppData\\Local', HOME = 'C:\\Users\\lenovo', SystemRoot = 'C:\\Windows' }
startup_timeout_ms = 20_000

ahSOLO · 10 months ago

I'm not able to run any MCPs on codex in native windows due to a winsocket error; switching to WSL resolves the issue


File "C:\Users\...\AppData\Roaming\uv\tools\serena-agent\Lib\site-packages\typing_extensions.py", line 2997, in call
    import asyncio.coroutines
  File "C:\Users\...\AppData\Roaming\uv\python\cpython-3.11.13-windows-x86_64-none\Lib\asyncio\init.py", line 42, in <module>
    from .windows_events import *
  File "C:\Users\...\AppData\Roaming\uv\python\cpython-3.11.13-windows-x86_64-none\Lib\asyncio\windows_events.py", line 8, in <module>
    import _overlapped
OSError: [WinError 10106] The requested service provider could not be loaded or initialized

T1nker-1220 · 10 months ago

This is working in my end this is really cool

domtisdell · 10 months ago

May help someone here. Also posted in #3408. Works for me on Windows 11 Pro/VSC/Codex CLI.

This config assumes MCP servers are installed globally with npm and launched via the global shims under %APPDATA%\npm.
Most servers weren't working - including Context7 - due to problems with outbound connections. Fixed by adding NODE_OPTIONS.

####################################
# MCP Servers (SANITIZED TEMPLATE)
# Replace <USER> and <..._API_KEY> placeholders before use.
# Tip: prefer setting keys via OS env vars instead of hard-coding.
####################################

# sequential-thinking
[mcp_servers.sequential-thinking]
command   = "C:\\Users\\<USER>\\AppData\\Roaming\\npm\\mcp-server-sequential-thinking.cmd"
args      = []
transport = "stdio"
startup_timeout_ms = 20000
[mcp_servers.sequential-thinking.env]
APPDATA      = "C:\\Users\\<USER>\\AppData\\Roaming"
LOCALAPPDATA = "C:\\Users\\<USER>\\AppData\\Local"
HOME         = "C:\\Users\\<USER>"
SystemRoot   = "C:\\Windows"
NODE_OPTIONS = "--dns-result-order=ipv4first"

# playwright (uses installed Chrome; headless)
[mcp_servers.playwright]
command   = "C:\\Users\\<USER>\\AppData\\Roaming\\npm\\mcp-server-playwright.cmd"
args      = ["--browser","chrome","--headless","--executable-path","C:\\Program Files\\Google\\Chrome\\Application\\chrome.exe"]
transport = "stdio"
startup_timeout_ms = 45000
[mcp_servers.playwright.env]
APPDATA      = "C:\\Users\\<USER>\\AppData\\Roaming"
LOCALAPPDATA = "C:\\Users\\<USER>\\AppData\\Local"
HOME         = "C:\\Users\\<USER>"
SystemRoot   = "C:\\Windows"
NODE_OPTIONS = "--dns-result-order=ipv4first"

# context7 (optional CONTEXT7_API_KEY)
[mcp_servers.context7]
command   = "C:\\Users\\<USER>\\AppData\\Roaming\\npm\\context7-mcp.cmd"
args      = []
transport = "stdio"
startup_timeout_ms = 60000
[mcp_servers.context7.env]
APPDATA      = "C:\\Users\\<USER>\\AppData\\Roaming"
LOCALAPPDATA = "C:\\Users\\<USER>\\AppData\\Local"
HOME         = "C:\\Users\\<USER>"
SystemRoot   = "C:\\Windows"
NODE_OPTIONS = "--dns-result-order=ipv4first"
# CONTEXT7_API_KEY = "<CONTEXT7_API_KEY>"

# Bright Data — direct server.js via node.exe
[mcp_servers.brightdata]
command   = "C:\\Program Files\\nodejs\\node.exe"
args      = ["C:\\Users\\<USER>\\AppData\\Roaming\\npm\\node_modules\\@brightdata\\mcp\\server.js"]
transport = "stdio"
startup_timeout_ms = 60000
[mcp_servers.brightdata.env]
API_TOKEN    = "<BRIGHTDATA_API_TOKEN>"
PRO_MODE     = "true"
APPDATA      = "C:\\Users\\<USER>\\AppData\\Roaming"
LOCALAPPDATA = "C:\\Users\\<USER>\\AppData\\Local"
HOME         = "C:\\Users\\<USER>"
SystemRoot   = "C:\\Windows"
NODE_OPTIONS = "--dns-result-order=ipv4first"

gjdklfjg · 10 months ago

There's a good way to do this: check the configuration paths for your commands. This way, you can configure multiple MCPs for uv, uvx, and npx. Here are some examples: [mcp_servers.serena] type = "stdio" command = 'C:\Users\lenovo\.local\bin\uv.exe' args = ["run", "--directory", "F:\Homework\MyMCP\serena", "serena-mcp-server"] env = { APPDATA = 'C:\Users\lenovo\AppData\Roaming', LOCALAPPDATA = 'C:\Users\lenovo\AppData\Local', HOME = 'C:\Users\lenovo', SystemRoot = 'C:\Windows' } startup_timeout_ms = 20_000

Love you, this is the first way I found that can run serena in my environment.
But I did a little bit adjustments to run it in VScode codex extension, here is my config:

[mcp_servers.serena]
type = "stdio"
command = "THE PATH TO YOUR uv.exe"
args = ["run", "--directory", "G:\\serena", "serena", "start-mcp-server", "--context", "codex"]
env = { APPDATA = "C:\\Users\\<YOUR WINDOWS ACCOUT USER ID>\\AppData\\Roaming", LOCALAPPDATA = "C:\\Users\\<YOUR WINDOWS ACCOUT USER ID>\\AppData\\Local", HOME = "C:\\Users\\<YOUR WINDOWS ACCOUT USER ID>", SystemRoot = "C:\\Windows" }
startup_timeout_ms = 20_000``

ahSOLO · 10 months ago

I was able to get my MCP servers working yesterday as well by adding these environmental variables

APPDATA = 'C:\Users\...\AppData\Roaming'
LOCALAPPDATA = 'C:\Users\...\AppData\Local'
DOTNET_ROOT = 'C:\Program Files\dotnet'
HOME='C:\Users\...'
SystemRoot='C:\Windows'

Everything else was identical to my setup for claude code (didn't have to convert npx or uvx to the executable). Thanks all!

SamuelMiller · 10 months ago

This is the format I used to get the MCP servers to work on Windows 11. You have to replace REDACTED with your own character sequence. Notice that I used "cmd" command instead of "npx"

`approval_policy = "never"
model = "gpt-5-codex"

[mcp_servers."firecrawl-mcp"]
command = "cmd"
args = ["/c", "npx", "-y", "firecrawl-mcp"]
startup_timeout_ms = 120000

[mcp_servers."firecrawl-mcp".env]
APPDATA = "C:\\Users\\Computer\\AppData\\Roaming"
LOCALAPPDATA = "C:\\Users\\Computer\\AppData\\Local"
HOME = "C:\\Users\\Computer"
SystemRoot = "C:\\Windows"
NODE_OPTIONS = "--dns-result-order=ipv4first"
FIRECRAWL_API_KEY = "fc-REDACTED"

[mcp_servers."playwright"]
command = "cmd"
args = ["/c", "npx", "-y", "@playwright/mcp@latest"]
startup_timeout_ms = 180000

[mcp_servers."playwright".env]
APPDATA = "C:\\Users\\Computer\\AppData\\Roaming"
LOCALAPPDATA = "C:\\Users\\Computer\\AppData\\Local"
HOME = "C:\\Users\\Computer"
SystemRoot = "C:\\Windows"
NODE_OPTIONS = "--dns-result-order=ipv4first"

[mcp_servers."context7"]
command = "cmd"
args = ["/c", "npx", "-y", "@upstash/context7-mcp", "--api-key", "ctx7sk-REDACTED"]
startup_timeout_ms = 120000

[mcp_servers."context7".env]
APPDATA = "C:\\Users\\Computer\\AppData\\Roaming"
LOCALAPPDATA = "C:\\Users\\Computer\\AppData\\Local"
HOME = "C:\\Users\\Computer"
SystemRoot = "C:\\Windows"
NODE_OPTIONS = "--dns-result-order=ipv4first"

[mcp_servers."supabase"]
command = "cmd"
args = ["/c", "npx", "-y", "@supabase/mcp-server-supabase@latest", "--read-only", "--project-ref=REDACTED"]
startup_timeout_ms = 120000

[mcp_servers."supabase".env]
APPDATA = "C:\\Users\\Computer\\AppData\\Roaming"
LOCALAPPDATA = "C:\\Users\\Computer\\AppData\\Local"
HOME = "C:\\Users\\Computer"
SystemRoot = "C:\\Windows"
NODE_OPTIONS = "--dns-result-order=ipv4first"
SUPABASE_ACCESS_TOKEN = "sbp_REDACTED"
`

ImViper · 10 months ago

mark,hope fix

yayaysya · 10 months ago

mark,hope fix

wbdb · 10 months ago

For Windows users, this works for me with Codex 0.38.0:

[mcp_servers.context7]
command = "cmd"
args = [
    "/c",
    "npx",
    "-y",
    "@upstash/context7-mcp",
    "--api-key",
    "YOUR_API_KEY",
]
env = { SystemRoot="C:\\Windows" }
startup_timeout_ms = 20_000

bestpika · 10 months ago

It looks like you can use it as long as there is information in the [.env].
The following settings can run correctly without any issues.

model = "gpt-5-codex"

[mcp_servers.dart]
type = "stdio"
command = 'c:\sdks\flutter\bin\dart.bat'
args = ["mcp-server"]

[mcp_servers.dart.env]
SYSTEMROOT = 'c:\windows'

[mcp_servers.context7]
type = 'stdio'
command = 'c:\nvm4w\nodejs\mcp-remote.cmd'
args = [
    'https://mcp.context7.com/mcp',
    '--header',
    'CONTEXT7-API-KEY',
]

[mcp_servers.context7.env]
SYSTEMROOT = 'c:\windows'

wangxuyang1221 · 9 months ago

Of course, if you are sse please use this uv tool install mcp-proxy, here is an example:当然，如果您是 sse，请使用此 uv 工具安装 mcp-proxy，以下是一个示例： [mcp_servers."graphiti-memory-stdio-via-proxy"] type = "stdio" 类型 = "stdio" command = 'C:\Users\lenovo\.local\bin\uvx.exe'命令 = 'C:\Users\lenovo\.local\bin\uvx.exe' args = ["mcp-proxy", "http://127.0.0.1:15627/sse"]参数 = ["mcp-proxy", "http://127.0.0.1:15627/sse"] env = { APPDATA = 'C:\Users\lenovo\AppData\Roaming', LOCALAPPDATA = 'C:\Users\lenovo\AppData\Local', HOME = 'C:\Users\lenovo', SystemRoot = 'C:\Windows' } startup_timeout_ms = 20_000

This works for me. I guess it should be these environmental variables that have played a role

Nenormalniy · 9 months ago

On windows 11, with this setup:

[mcp_servers."context7"]
command = "cmd"
args = [
    "/c",
    "npx",
    "-y",
    "@upstash/context7-mcp",
    "--api-key",
    "ctx7sk-REDACTED",
]
startup_timeout_ms = 120000

[mcp_servers."context7".env]
APPDATA = "C:\Users\user\AppData\Roaming"
LOCALAPPDATA = "C:\Users\user\AppData\Local"
HOME = "C:\Users\user"
SystemRoot = "C:\Windows"
NODE_OPTIONS = "--dns-result-order=ipv4first"

I have this error on typing "codex" command:

Error loading configuration: TOML parse error at line 25, column 16
   |
25 | APPDATA = "C:\Users\user\AppData\Roaming"
   |                ^
too few unicode value digits, expected unicode hexadecimal value

Double-slashing fixed this:

[mcp_servers."context7"]
command = "cmd"
args = [
    "/c",
    "npx",
    "-y",
    "@upstash/context7-mcp",
    "--api-key",
    "ctx7sk-REDACTED",
]
startup_timeout_ms = 120000

[mcp_servers."context7".env]
APPDATA = "C:\\Users\\user\\AppData\\Roaming"
LOCALAPPDATA = "C:\\Users\\user\\AppData\\Local"
HOME = "C:\\Users\\user"
SystemRoot = "C:\\Windows"
NODE_OPTIONS = "--dns-result-order=ipv4first"

sonomirco · 8 months ago

Hi all,
Can I have help using a stdio mcp running via an .exe file?

[mcp_servers.autodeskAECModel]
type = "stdio"
command = "C:\\Users\\xxx\\Documents\\aps-graphql\\src\\apsMcp.StdioServer\\bin\\Release\\net9.0\\win-x64\\publish\\apsMcp.StdioServer.exe"]
env = { "APS_CLIENT_ID" = "id", "APS_CLIENT_SECRET" = "secret", "APS_CALLBACK_URL" = "callback" }

I keep having this error
MCP client for autodeskAECModel failed to start: handshaking with MCP server failed: connection closed: initialize response

etraut-openai contributor · 7 months ago

We have fixed many mcp-related bugs for Windows since this bug was first filed. If you're still seeing problems with the latest version of codex, please open a new bug report with details.

sonomirco · 7 months ago

Hi all, Can I have help using a stdio mcp running via an .exe file? `` [mcp_servers.autodeskAECModel] type = "stdio" command = "C:\\Users\\xxx\\Documents\\aps-graphql\\src\\apsMcp.StdioServer\\bin\\Release\\net9.0\\win-x64\\publish\\apsMcp.StdioServer.exe"] env = { "APS_CLIENT_ID" = "id", "APS_CLIENT_SECRET" = "secret", "APS_CALLBACK_URL" = "callback" } ` I keep having this error MCP client for autodeskAECModel failed to start: handshaking with MCP server failed: connection closed: initialize response`

I find the problem.
In the code, I was having some Write.Console for debugging! Interesting, Claude Code don't care; instead, Codex was literally causing the handshaking to fail.