MCPs do not work natively on Windows (Powershell)

Same problem here.

I can confirm that the problem has not been fixed. Despite several comments confirming this, the previous issue was simply closed.

With v32.0 also: 🖐  MCP client for context7 failed to start: missing field user_agent - https://github.com/openai/codex/issues/3424

I'm trying to implement my MCP.
But no matter what I do, I get... Works with claude, other, but not with codex. I assume it codex issue.
🖐  MCP client for xxx-mcp failed to start: request timed out

PS C:\Users\xxx> codex --version
codex-cli 0.31.0

Same issue with 0.34.0, this is not related to powershell. I have the problem using good ol' cmd.exe: MCP client for context7 failed to start: request timed out

This issue was intended to be fixed in 0.31.0 via https://github.com/openai/codex/pull/3182 but that fix is not effective, no matter how long the timeout you specify. you now just wait longer before the error message appears.

Check out my solution! 😉
https://github.com/openai/codex/issues/3385

@sfz009900 I tried it that way, but then Codex no longer loads in VS Code at all.
We've had this error for almost a month now :(

[mcp_servers.context7]
command = "C:\\Program Files\\nodejs\\npx.cmd"
args = ["-y", "@upstash/context7-mcp"]
startup_timeout_ms = 20_000
env = {
  APPDATA="C:\\Users\\myname\\AppData\\Roaming",
  LOCALAPPDATA="C:\\Users\\myname\\AppData\\Local",
  HOME="C:\\Users\\myname",
  SystemRoot="C:\\Windows",
  ComSpec="C:\\Windows\\System32\\cmd.exe",
}

Yo @wbdb , just checked and it's all good 👍

<img width="547" height="712" alt="Image" src="https://github.com/user-attachments/assets/fb1776c5-b8a7-45e6-9fc2-7116c72dd09b" />

ver=v0.5.8

Yo @wbdb, here's my setup!:

[mcp_servers.context7]
command = "F:\\software\\nodejsold\\npx.cmd"
args = ["-y", "@upstash/context7-mcp", "--api-key", "xxxxxxxxxxxxxxxxxxxxxx"]
startup_timeout_ms = 20_000
env = { APPDATA="C:\\Users\\test004\\AppData\\Roaming", LOCALAPPDATA="C:\\Users\\test004\\AppData\\Local", HOME="C:\\Users\\test004", SystemRoot="C:\\Windows", ComSpec="C:\\Windows\\System32\\cmd.exe", NPM_CONFIG_REGISTRY="https://registry.npmmirror.com" }

Hey @wbdb, you free to hop on a remote sesh with me via todesk? Kinda curious what went wrong, lol. 😄

same here, no windows native support!

Yo @wbdb, here's my setup!: `` [mcp_servers.context7] command = "F:\\software\\nodejsold\\npx.cmd" args = ["-y", "@upstash/context7-mcp", "--api-key", "xxxxxxxxxxxxxxxxxxxxxx"] startup_timeout_ms = 20_000 env = { APPDATA="C:\\Users\\test004\\AppData\\Roaming", LOCALAPPDATA="C:\\Users\\test004\\AppData\\Local", HOME="C:\\Users\\test004", SystemRoot="C:\\Windows", ComSpec="C:\\Windows\\System32\\cmd.exe", NPM_CONFIG_REGISTRY="https://registry.npmmirror.com" } ``

THANK YOU!

it works!

---

using npm (npx)
[mcp_servers.context7]
command = 'C:\Program Files\nodejs\npx.cmd'
args = ["-y", "@upstash/context7-mcp@latest"]
env = { APPDATA='C:\Users\\{username}\AppData\Roaming', LOCALAPPDATA='C:\Users\\{username}\AppData\Local', HOME='C:\Users\\{username}', SystemRoot='C:\Windows' }
startup_timeout_ms = 20_000

using bun (bunx)
[mcp_servers.context7]
command = "bunx"
args = ["-y", "@upstash/context7-mcp@latest"]
env = { APPDATA='C:\Users\\{username}\AppData\Roaming', LOCALAPPDATA='C:\Users\\{username}\AppData\Local', HOME='C:\Users\\{username}', SystemRoot='C:\Windows' }
startup_timeout_ms = 20_000

Adding the env variables also fixed it for me, thanks!

[mcp_servers.gdai-mcp]
command = "uv"
args = ["run", "C:/{project folder}/addons/gdai-mcp-plugin/gdai_mcp_server.py"]
env = { APPDATA='C:\Users\{username}\AppData\Roaming', LOCALAPPDATA='C:\Users\{username}\AppData\Local', HOME='C:\Users\{username}', SystemRoot='C:\Windows' }
startup_timeout_ms = 20_000

@seocorp @TheCircus Did you get it working in Codex CLI only or in the VS Code Extension also? I would find it most helpful here at the moment; with Codex CLI, I'll continue to use WSL.

@sfz009900 I'm from Germany, so I'm not familiar with the software or client todesk. All I see on the page are Chinese characters :). Do you also have Windows 11 (Pro) 24H2?

node --version: 22.18.0
npm --version: 11.5.2

where npx
C:\Program Files\nodejs\npx
C:\Program Files\nodejs\npx.cmd
C:\Users\myname\AppData\Roaming\npm\npx
C:\Users\myname\AppData\Roaming\npm\npx.cmd

config.toml for Codex CLI/VSCode Extension:

# ========================
#  Model & parameters
# ========================
model = "gpt-5"
model_context_window = 400000
max_tokens = 400000
approval_policy = "never"
sandbox_mode = "workspace-write"

temperature = 0.1
top_p = 1.0
model_reasoning_effort = "high"
model_verbosity = "high"
show_raw_agent_reasoning = true

# ======================================================
#  Servers
# ======================================================

# --- Fetch ---
[mcp_servers.Fetch]
command = "C:\\Program Files\\NodeJS\\npx.cmd"
args = ["-y", "@wordbricks/fetch-mcp@latest", "--transport", "stdio"]
startup_timeout_ms = 18000
env = { APPDATA = "C:\\Users\\Fer\\AppData\\Roaming", LOCALAPPDATA = "C:\\Users\\Fer\\AppData\\Local", HOME = "C:\\Users\\Fer", SystemRoot = "C:\\Windows", ComSpec = "C:\\Windows\\System32\\cmd.exe" }

# --- Time ---
[mcp_servers.Time]
command = "C:\\Program Files\\NodeJS\\npx.cmd"
args = ["-y", "@dandeliongold/mcp-time@latest"]
startup_timeout_ms = 18000
env = { APPDATA = "C:\\Users\\Fer\\AppData\\Roaming", LOCALAPPDATA = "C:\\Users\\Fer\\AppData\\Local", HOME = "C:\\Users\\Fer", SystemRoot = "C:\\Windows", ComSpec = "C:\\Windows\\System32\\cmd.exe" }

# --- Context7 ---
[mcp_servers.Context7]
command = "C:\\Program Files\\NodeJS\\npx.cmd"
args = ["-y", "@upstash/context7-mcp"]
startup_timeout_ms = 18000
env = { APPDATA = "C:\\Users\\Fer\\AppData\\Roaming", LOCALAPPDATA = "C:\\Users\\Fer\\AppData\\Local", HOME = "C:\\Users\\Fer", SystemRoot = "C:\\Windows", ComSpec = "C:\\Windows\\System32\\cmd.exe" }

# --- Deepwiki ---
[mcp_servers.DeepWiki]
command = "C:\\Program Files\\NodeJS\\npx.cmd"
args = ["-y", "mcp-deepwiki@latest"]
startup_timeout_ms = 18000
env = { APPDATA = "C:\\Users\\Fer\\AppData\\Roaming", LOCALAPPDATA = "C:\\Users\\Fer\\AppData\\Local", HOME = "C:\\Users\\Fer", SystemRoot = "C:\\Windows", ComSpec = "C:\\Windows\\System32\\cmd.exe" }

# --- Playwright ---
[mcp_servers.PlayWright]
command = "C:\\Program Files\\NodeJS\\npx.cmd"
args = ["-y", "@playwright/mcp@latest"]
startup_timeout_ms = 18000
env = { APPDATA = "C:\\Users\\Fer\\AppData\\Roaming", LOCALAPPDATA = "C:\\Users\\Fer\\AppData\\Local", HOME = "C:\\Users\\Fer", SystemRoot = "C:\\Windows", ComSpec = "C:\\Windows\\System32\\cmd.exe" }

Codex CLI Terminal App - Powershell 7:

>_ You are using OpenAI Codex in C:\Users\Fer

 To get started, describe a task or try one of these commands:

 /init - create an AGENTS.md file with instructions for Codex
 /status - show current session configuration and token usage
 /approvals - choose what Codex can do without approval
 /model - choose what model and reasoning effort to use

/mcp

🔌  MCP Tools

  • Server: Playwright
    • Command: C:\Program Files\NodeJS\npx.cmd -y @playwright/mcp@latest
    • Tools: browser_click, browser_close, browser_console_messages, browser_drag, browser_evaluate,
browser_file_upload, browser_fill_form, browser_handle_dialog, browser_hover, browser_install, browser_navigate,
browser_navigate_back, browser_network_requests, browser_press_key, browser_resize, browser_select_option,
browser_snapshot, browser_tabs, browser_take_screenshot, browser_type, browser_wait_for

  • Server: Context7
    • Command: C:\Program Files\NodeJS\npx.cmd -y @upstash/context7-mcp
    • Tools: get-library-docs, resolve-library-id

  • Server: Fetch
    • Command: C:\Program Files\NodeJS\npx.cmd -y @wordbricks/fetch-mcp@latest --transport stdio
    • Tools: fetch

  • Server: Time
    • Command: C:\Program Files\NodeJS\npx.cmd -y @dandeliongold/mcp-time@latest
    • Tools: getCurrentTime, getTimeDifference

  • Server: DeepWiki
    • Command: C:\Program Files\NodeJS\npx.cmd -y mcp-deepwiki@latest
    • Tools: deepwiki_fetch

For what it's worth, another example of working mcp servers 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"

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-key",
]
env = { SystemRoot="C:\\Windows" }
startup_timeout_ms = 20_000

I have a simpler solution if you don't mind manually updating MCPs.

Install bun, then use bun install -g to install MCP packages globally just like you would install any other MCP. Then run bun pm bin -g to get bun's global bin path and add it to your PATH environment variable.

For example, if I install @upstash/context7-mcp, after installation I only need to configure:

[mcp_servers.context7]
command = 'context7-mcp.exe'

This approach bypasses the timeout issues with npx/uvx on Windows by using pre-installed executables instead of on-demand package execution.

This might indicate that if you don't provide env = { SystemRoot="C:\Windows" }, you need to execute .exe binary executables directly. But if it's a .cmd file, it will cause timeout issues.

Hi everyone, I've opened a follow-up PR at #3994 that includes the fix and adds a comprehensive test suite.

This new suite empirically validates exactly which environment variables are critical for MCP servers (especially those using npx) to function correctly on Windows. The tests confirm that PATH, APPDATA, and SYSTEMROOT are all necessary.

By adding APPDATA and SYSTEMROOT to the default environment, this PR provides a proper fix that should resolve the timeout issues without requiring the manual env workarounds in config.toml.

config.toml 用于 Codex CLI/VSCode 扩展： `` # ======================== # Model & parameters # ======================== model = "gpt-5" model_context_window = 400000 max_tokens = 400000 approval_policy = "never" sandbox_mode = "workspace-write" temperature = 0.1 top_p = 1.0 model_reasoning_effort = "high" model_verbosity = "high" show_raw_agent_reasoning = true # ====================================================== # Servers # ====================================================== # --- Fetch --- [mcp_servers.Fetch] command = "C:\\Program Files\\NodeJS\\npx.cmd" args = ["-y", "@wordbricks/fetch-mcp@latest", "--transport", "stdio"] startup_timeout_ms = 18000 env = { APPDATA = "C:\\Users\\Fer\\AppData\\Roaming", LOCALAPPDATA = "C:\\Users\\Fer\\AppData\\Local", HOME = "C:\\Users\\Fer", SystemRoot = "C:\\Windows", ComSpec = "C:\\Windows\\System32\\cmd.exe" } # --- Time --- [mcp_servers.Time] command = "C:\\Program Files\\NodeJS\\npx.cmd" args = ["-y", "@dandeliongold/mcp-time@latest"] startup_timeout_ms = 18000 env = { APPDATA = "C:\\Users\\Fer\\AppData\\Roaming", LOCALAPPDATA = "C:\\Users\\Fer\\AppData\\Local", HOME = "C:\\Users\\Fer", SystemRoot = "C:\\Windows", ComSpec = "C:\\Windows\\System32\\cmd.exe" } # --- Context7 --- [mcp_servers.Context7] command = "C:\\Program Files\\NodeJS\\npx.cmd" args = ["-y", "@upstash/context7-mcp"] startup_timeout_ms = 18000 env = { APPDATA = "C:\\Users\\Fer\\AppData\\Roaming", LOCALAPPDATA = "C:\\Users\\Fer\\AppData\\Local", HOME = "C:\\Users\\Fer", SystemRoot = "C:\\Windows", ComSpec = "C:\\Windows\\System32\\cmd.exe" } # --- Deepwiki --- [mcp_servers.DeepWiki] command = "C:\\Program Files\\NodeJS\\npx.cmd" args = ["-y", "mcp-deepwiki@latest"] startup_timeout_ms = 18000 env = { APPDATA = "C:\\Users\\Fer\\AppData\\Roaming", LOCALAPPDATA = "C:\\Users\\Fer\\AppData\\Local", HOME = "C:\\Users\\Fer", SystemRoot = "C:\\Windows", ComSpec = "C:\\Windows\\System32\\cmd.exe" } # --- Playwright --- [mcp_servers.PlayWright] command = "C:\\Program Files\\NodeJS\\npx.cmd" args = ["-y", "@playwright/mcp@latest"] startup_timeout_ms = 18000 env = { APPDATA = "C:\\Users\\Fer\\AppData\\Roaming", LOCALAPPDATA = "C:\\Users\\Fer\\AppData\\Local", HOME = "C:\\Users\\Fer", SystemRoot = "C:\\Windows", ComSpec = "C:\\Windows\\System32\\cmd.exe" } ` Codex CLI 终端应用 - Powershell 7： ` >_ You are using OpenAI Codex in C:\Users\Fer To get started, describe a task or try one of these commands: /init - create an AGENTS.md file with instructions for Codex /status - show current session configuration and token usage /approvals - choose what Codex can do without approval /model - choose what model and reasoning effort to use /mcp 🔌 MCP Tools • Server: Playwright • Command: C:\Program Files\NodeJS\npx.cmd -y @playwright/mcp@latest • Tools: browser_click, browser_close, browser_console_messages, browser_drag, browser_evaluate, browser_file_upload, browser_fill_form, browser_handle_dialog, browser_hover, browser_install, browser_navigate, browser_navigate_back, browser_network_requests, browser_press_key, browser_resize, browser_select_option, browser_snapshot, browser_tabs, browser_take_screenshot, browser_type, browser_wait_for • Server: Context7 • Command: C:\Program Files\NodeJS\npx.cmd -y @upstash/context7-mcp • Tools: get-library-docs, resolve-library-id • Server: Fetch • Command: C:\Program Files\NodeJS\npx.cmd -y @wordbricks/fetch-mcp@latest --transport stdio • Tools: fetch • Server: Time • Command: C:\Program Files\NodeJS\npx.cmd -y @dandeliongold/mcp-time@latest • Tools: getCurrentTime, getTimeDifference • Server: DeepWiki • Command: C:\Program Files\NodeJS\npx.cmd -y mcp-deepwiki@latest • Tools: deepwiki_fetch ``

config.toml for Codex CLI/VSCode Extension: `` # ======================== # Model & parameters # ======================== model = "gpt-5" model_context_window = 400000 max_tokens = 400000 approval_policy = "never" sandbox_mode = "workspace-write" temperature = 0.1 top_p = 1.0 model_reasoning_effort = "high" model_verbosity = "high" show_raw_agent_reasoning = true # ====================================================== # Servers # ====================================================== # --- Fetch --- [mcp_servers.Fetch] command = "C:\\Program Files\\NodeJS\\npx.cmd" args = ["-y", "@wordbricks/fetch-mcp@latest", "--transport", "stdio"] startup_timeout_ms = 18000 env = { APPDATA = "C:\\Users\\Fer\\AppData\\Roaming", LOCALAPPDATA = "C:\\Users\\Fer\\AppData\\Local", HOME = "C:\\Users\\Fer", SystemRoot = "C:\\Windows", ComSpec = "C:\\Windows\\System32\\cmd.exe" } # --- Time --- [mcp_servers.Time] command = "C:\\Program Files\\NodeJS\\npx.cmd" args = ["-y", "@dandeliongold/mcp-time@latest"] startup_timeout_ms = 18000 env = { APPDATA = "C:\\Users\\Fer\\AppData\\Roaming", LOCALAPPDATA = "C:\\Users\\Fer\\AppData\\Local", HOME = "C:\\Users\\Fer", SystemRoot = "C:\\Windows", ComSpec = "C:\\Windows\\System32\\cmd.exe" } # --- Context7 --- [mcp_servers.Context7] command = "C:\\Program Files\\NodeJS\\npx.cmd" args = ["-y", "@upstash/context7-mcp"] startup_timeout_ms = 18000 env = { APPDATA = "C:\\Users\\Fer\\AppData\\Roaming", LOCALAPPDATA = "C:\\Users\\Fer\\AppData\\Local", HOME = "C:\\Users\\Fer", SystemRoot = "C:\\Windows", ComSpec = "C:\\Windows\\System32\\cmd.exe" } # --- Deepwiki --- [mcp_servers.DeepWiki] command = "C:\\Program Files\\NodeJS\\npx.cmd" args = ["-y", "mcp-deepwiki@latest"] startup_timeout_ms = 18000 env = { APPDATA = "C:\\Users\\Fer\\AppData\\Roaming", LOCALAPPDATA = "C:\\Users\\Fer\\AppData\\Local", HOME = "C:\\Users\\Fer", SystemRoot = "C:\\Windows", ComSpec = "C:\\Windows\\System32\\cmd.exe" } # --- Playwright --- [mcp_servers.PlayWright] command = "C:\\Program Files\\NodeJS\\npx.cmd" args = ["-y", "@playwright/mcp@latest"] startup_timeout_ms = 18000 env = { APPDATA = "C:\\Users\\Fer\\AppData\\Roaming", LOCALAPPDATA = "C:\\Users\\Fer\\AppData\\Local", HOME = "C:\\Users\\Fer", SystemRoot = "C:\\Windows", ComSpec = "C:\\Windows\\System32\\cmd.exe" } ` Codex CLI Terminal App - Powershell 7: ` >_ You are using OpenAI Codex in C:\Users\Fer To get started, describe a task or try one of these commands: /init - create an AGENTS.md file with instructions for Codex /status - show current session configuration and token usage /approvals - choose what Codex can do without approval /model - choose what model and reasoning effort to use /mcp 🔌 MCP Tools • Server: Playwright • Command: C:\Program Files\NodeJS\npx.cmd -y @playwright/mcp@latest • Tools: browser_click, browser_close, browser_console_messages, browser_drag, browser_evaluate, browser_file_upload, browser_fill_form, browser_handle_dialog, browser_hover, browser_install, browser_navigate, browser_navigate_back, browser_network_requests, browser_press_key, browser_resize, browser_select_option, browser_snapshot, browser_tabs, browser_take_screenshot, browser_type, browser_wait_for • Server: Context7 • Command: C:\Program Files\NodeJS\npx.cmd -y @upstash/context7-mcp • Tools: get-library-docs, resolve-library-id • Server: Fetch • Command: C:\Program Files\NodeJS\npx.cmd -y @wordbricks/fetch-mcp@latest --transport stdio • Tools: fetch • Server: Time • Command: C:\Program Files\NodeJS\npx.cmd -y @dandeliongold/mcp-time@latest • Tools: getCurrentTime, getTimeDifference • Server: DeepWiki • Command: C:\Program Files\NodeJS\npx.cmd -y mcp-deepwiki@latest • Tools: deepwiki_fetch ``

You are right , I love you!

I think this issue is no longer relevant, so I'm closing. If you see problems with mcp servers on Windows with the latest version of codex, please open a new issue and provide details. Use the /feedback slash command to upload the session if applicable.