Connect an MCP Client that only supports local (stdio) servers to a Remote MCP Server, with auth support:
Note: this is a working proof-of-concept but should be considered experimental.
So far, the majority of MCP servers in the wild are installed locally, using the stdio transport. This has some benefits: both the client and the server can implicitly trust each other as the user has granted them both permission to run. Adding secrets like API keys can be done using environment variables and never leave your machine. And building on npx and uvx has allowed users to avoid explicit install steps, too.
But there's a reason most software that could be moved to the web did get moved to the web: it's so much easier to find and fix bugs & iterate on new features when you can push updates to all your users with a single deploy.
With the MCP Authorization specification nearing completion, we now have a secure way of sharing our MCP servers with the world without running code on user's laptops. Or at least, you would, if all the popular MCP clients supported it yet. Most are stdio-only, and those that do support HTTP+SSE don't yet support the OAuth flows required.
That's where mcp-remote comes in. As soon as your chosen MCP client supports remote, authorized servers, you can remove it. Until that time, drop in this one liner and dress for the MCP clients you want!
All the most popular MCP clients (Claude Desktop, Cursor & Windsurf) use the following config format:
{
"mcpServers": {
"remote-example": {
"command": "npx",
"args": [
"mcp-remote",
"https://remote.mcp.server/sse"
]
}
}
}- If
npxis producing errors, consider adding-yas the first argument to auto-accept the installation of themcp-remotepackage.
"command": "npx",
"args": [
"-y"
"mcp-remote",
"https://remote.mcp.server/sse"
]- To force
npxto always check for an updated version ofmcp-remote, add the@latestflag:
"args": [
"mcp-remote@latest",
"https://remote.mcp.server/sse"
]- To force
mcp-remoteto ignore any existing access tokens and begin the authorization flow anew, pass--clean.
"args": [
"mcp-remote",
"https://remote.mcp.server/sse",
"--clean"
]- To change which port
mcp-remotelistens for an OAuth redirect (by default3334), add an additional argument after the server URL. Note that whatever port you specify, if it is unavailable an open port will be chosen at random.
"args": [
"mcp-remote",
"https://remote.mcp.server/sse",
"9696"
]In order to add an MCP server to Claude Desktop you need to edit the configuration file located at:
- macOS:
~/Library/Application Support/Claude/claude_desktop_config.json - Windows:
%APPDATA%\Claude\claude_desktop_config.json
If it does not exist yet, you may need to enable it under Settings > Developer.
Restart Claude Desktop to pick up the changes in the configuration file. Upon restarting, you should see a hammer icon in the bottom right corner of the input box.
Official Docs. The configuration file is located at ~/.cursor/mcp.json.
As of version 0.48.0, Cursor supports unauthed SSE servers directly. If your MCP server is using the official MCP OAuth authorization protocol, you still need to add a "command" server and call mcp-remote.
Official Docs. The configuration file is located at ~/.codeium/windsurf/mcp_config.json.
For instructions on building & deploying remote MCP servers, including acting as a valid OAuth client, see the following resources:
In particular, see:
- https://github.com/cloudflare/workers-oauth-provider for defining an MCP-comlpiant OAuth server in Cloudflare Workers
- https://github.com/cloudflare/agents/tree/main/examples/mcp for defining an
McpAgentusing theagentsframework.
For more information about testing these servers, see also:
Know of more resources you'd like to share? Please add them to this Readme and send a PR!
mcp-remote stores all the credential information inside ~/.mcp-auth (or wherever your MCP_REMOTE_CONFIG_DIR points to). If you're having persistent issues, try running:
rm -rf ~/.mcp-authThen restarting your MCP client.
Make sure that the version of Node you have installed is 18 or higher. Claude Desktop will use your system version of Node, even if you have a newer version installed elsewhere.
When modifying claude_desktop_config.json it can helpful to completely restart Claude
You may run into issues if you are behind a VPN, you can try setting the NODE_EXTRA_CA_CERTS
environment variable to point to the CA certificate file. If using claude_desktop_config.json,
this might look like:
{
"mcpServers": {
"remote-example": {
"command": "npx",
"args": [
"mcp-remote",
"https://remote.mcp.server/sse"
],
"env": {
"NODE_EXTRA_CA_CERTS": "{your CA certificate file path}.pem"
}
}
}
}- Follow Claude Desktop logs in real-time
- MacOS / Linux:
tail -n 20 -F ~/Library/Logs/Claude/mcp*.log - For bash on WSL:
tail -n 20 -f "C:\Users\YourUsername\AppData\Local\Claude\Logs\mcp.log" - Powershell:
Get-Content "C:\Users\YourUsername\AppData\Local\Claude\Logs\mcp.log" -Wait -Tail 20
If you encounter the following error, returned by the /callback URL:
Authentication Error
Token exchange failed: HTTP 400
You can run rm -rf ~/.mcp-auth to clear any locally stored state and tokens.
Run the following on the command line (not from an MCP server):
npx -p mcp-remote@latest mcp-remote-client https://remote.mcp.server/sseThis will run through the entire authorization flow and attempt to list the tools & resources at the remote URL. Pair this with --clean or after running rm -rf ~/.mcp-auth to see if stale credentials are your problem, otherwise hopefully the issue will be more obvious in these logs than those in your MCP client.