/docs/troubleshooting.md

# Troubleshooting

## General tips

- Run `npx chrome-devtools-mcp@latest --help` to test if the MCP server runs on your machine.
- Make sure that your MCP client uses the same npm and node version as your terminal.
- When configuring your MCP client, try using the `--yes` argument to `npx` to
  auto-accept installation prompt.
- Find a specific error in the output of the `chrome-devtools-mcp` server.
  Usually, if your client is an IDE, logs would be in the Output pane.
- Search the [GitHub repository issues and discussions](https://github.com/ChromeDevTools/chrome-devtools-mcp) for help or existing similar problems.

## Debugging

Start the MCP server with debugging enabled and a log file:

- `DEBUG=* npx chrome-devtools-mcp@latest --log-file=/path/to/chrome-devtools-mcp.log`

Using `.mcp.json` to debug while using a client:

```json
{
  "mcpServers": {
    "chrome-devtools": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "chrome-devtools-mcp@latest",
        "--log-file",
        "/path/to/chrome-devtools-mcp.log"
      ],
      "env": {
        "DEBUG": "*"
      }
    }
  }
}
```

## Specific problems

### `Error [ERR_MODULE_NOT_FOUND]: Cannot find module ...`

This usually indicates either a non-supported Node version is in use or that the
`npm`/`npx` cache is corrupted. Try clearing the cache, uninstalling
`chrome-devtools-mcp` and installing it again. Clear the cache by running:

```sh
rm -rf ~/.npm/_npx # NOTE: this might remove other installed npx executables.
npm cache clean --force
```

### `Target closed` error

This indicates that the browser could not be started. Make sure that no Chrome
instances are running or close them. Make sure you have the latest stable Chrome
installed and that [your system is able to run Chrome](https://support.google.com/chrome/a/answer/7100626?hl=en).

### Chrome crashes on macOS when using Web Bluetooth

On macOS, Chrome launched by an MCP client application (such as Claude Desktop) may crash when a Web Bluetooth prompt appears. This is caused by a macOS privacy permission violation (TCC).

To resolve this, grant Bluetooth permission to the MCP client application in `System Settings > Privacy & Security > Bluetooth`. After granting permission, restart the client application and start a new MCP session.

### Remote debugging between virtual machine (VM) and host fails

When attempting to connect to Chrome running on a host machine from within a virtual machine (VM), Chrome may reject the connection due to 'Host' header validation. You can bypass this restriction by creating an SSH tunnel from the VM to the host. In the VM, run:

```sh
ssh -N -L 127.0.0.1:9222:127.0.0.1:9222 <user>@<host-ip>
```

Point the MCP connection inside the VM to `http://127.0.0.1:9222`. This allows DevTools to reach the host browser without triggering the Host validation error.

### Operating system sandboxes

Some MCP clients allow sandboxing the MCP server using macOS Seatbelt or Linux
containers. If sandboxes are enabled, `chrome-devtools-mcp` is not able to start
Chrome that requires permissions to create its own sandboxes. As a workaround,
either disable sandboxing for `chrome-devtools-mcp` in your MCP client or use
`--browser-url` to connect to a Chrome instance that you start manually outside
of the MCP client sandbox.

### WSL

By default, `chrome-devtools-mcp` in WSL requires Chrome to be installed within the Linux environment. While it normally attempts to launch Chrome on the Windows side, this currently fails due to a [known WSL issue](https://github.com/microsoft/WSL/issues/14201). Ensure you are using a [Linux distribution compatible with Chrome](https://support.google.com/chrome/a/answer/7100626).

Possible workarounds include:

- **Install Google Chrome in WSL:**
  - `wget https://dl.google.com/linux/direct/google-chrome-stable_current_amd64.deb`
  - `sudo dpkg -i google-chrome-stable_current_amd64.deb`

- **Use Mirrored networking:**
  1. Configure [Mirrored networking for WSL](https://learn.microsoft.com/en-us/windows/wsl/networking).
  2. Start Chrome on the Windows side with:
     `chrome.exe --remote-debugging-port=9222 --user-data-dir=C:\path\to\dir`
  3. Start `chrome-devtools-mcp` with:
     `npx chrome-devtools-mcp --browser-url http://127.0.0.1:9222`

- **Use Powershell or Git Bash** instead of WSL.

### Connection timeouts with `--autoConnect`

If you are using the `--autoConnect` flag and tools like `list_pages`, `new_page`, or `navigate_page` fail with a timeout (e.g., `ProtocolError: Network.enable timed out` or `The socket connection was closed unexpectedly`), this usually means the MCP server cannot handshake with the running Chrome instance correctly. Ensure:

1. Chrome 144+ is **already** running.
2. Remote debugging is enabled in Chrome via `chrome://inspect/#remote-debugging`.
3. You have allowed the remote debugging connection prompt in the browser.
4. There is no other MCP server or tool trying to connect to the same debugging port.