One URL for your MCP server, in every client: claude.ai, Claude Desktop, Claude Code, ChatGPT and VS Code

Oct 9, 2026

A remote MCP server URL is a public HTTPS address, usually ending in /mcp, that speaks Streamable HTTP. Add it as a custom connector in claude.ai or ChatGPT, with claude mcp add --transport http in Claude Code, or as an http server in VS Code’s mcp.json. The client then runs an OAuth sign-in.

This page is the reference the other guides on this blog point to. It covers what the URL is, how to get one for a server on your own machine, and the exact steps for each client.

What an MCP server URL is

An MCP server can talk to a client in two ways. Over stdio, the client launches the server as a child process and they exchange messages on stdin and stdout. Over Streamable HTTP, the server listens at an HTTP endpoint and any client that can reach it sends requests there. The endpoint path is usually /mcp, so a URL looks like this:

https://notes-anatoly.tunnel.mcpwarp.io/mcp

The URL is what you paste into a client. If the client runs on your machine (Claude Code, VS Code), http://localhost:8765/mcp can work. If the client runs in someone else’s data centre (claude.ai, ChatGPT), the request comes from their servers, which can’t reach your laptop, so the URL has to be public HTTPS. Why claude.ai can’t connect to your local MCP server explains that in detail, and What is MCP covers the protocol itself. A server that only speaks stdio needs a bridge to HTTP first; Use a stdio MCP server in claude.ai and ChatGPT without deploying it covers the options.

A lot of people still wire remote servers into Claude Desktop through JSON config and mcp-remote, which had about 5.0 million npm downloads between 9 September and 8 October 2026 (npm API). mcp-remote goes the other direction from a tunnel: it lets a stdio-only client reach a server that already has a URL. Every client below can take the URL directly.

Get a URL for a server on your machine

The rest of this page works with any public Streamable HTTP URL: your own reverse proxy, Cloudflare Tunnel with Access, ngrok with an auth layer, or mcptunnels (free, but the URL expires after 24 hours). ngrok alternative for MCP compares the tunnels. The examples use MCP Warp, the tunnel we build.

The first run, once:

Install the CLI (Homebrew shown; Scoop and Linux packages are in Get started):
Terminal window
```
brew tap mcpwarp/tap
brew trust --tap mcpwarp/tap
brew install --cask mcpwarp
```
Sign in at web.mcpwarp.io to create your account and choose a username.

Add the server to ~/.mcpwarp/config.json. An HTTP server you already run:

{
  "servers": [
    { "name": "notes", "kind": "http", "url": "http://127.0.0.1:8765/mcp" }
  ]
}

Or a stdio server that mcpwarp should spawn itself:

{
  "servers": [
    {
      "name": "blender",
      "kind": "stdio",
      "command": "uvx",
      "args": ["blender-mcp"],
      "env": { "BLENDER_PATH": "/Applications/Blender.app" }
    }
  ]
}

Check the config, log in and start the tunnel:

mcpwarp status
mcpwarp login
mcpwarp up

NAME     KIND   URL
notes    http   https://notes-anatoly.tunnel.mcpwarp.io/mcp

After that, every session is mcpwarp login (when your session expires) and mcpwarp up. In the full-screen view, c copies the selected row’s URL.

Each server gets its own subdomain, <name>-<username>.tunnel.mcpwarp.io, instead of a path under one shared host. Clients such as VS Code and Claude Desktop cache OAuth credentials per origin, so two servers on one host could clobber each other’s tokens. Why one subdomain per server has the detail.

Two things to keep in mind. mcpwarp up has to be running on your machine, or the URL returns 503. And the Free plan covers 100 requests a month and 1 server; every HTTP request a client makes counts. See Limits and quotas.

Add it to each client

claude.ai and Claude Desktop

Both use custom connectors, and Anthropic documents the same steps for each.

In claude.ai, go to Customize > Connectors (Pro/Max), click “+ Add”, then “Add custom connector”. The steps are in Anthropic’s help article on custom connectors.
Give it a name and paste the URL.
Click Connect and complete the OAuth sign-in when prompted.

Custom connectors are available “for users on Free, Pro, Max, Team, and Enterprise plans”, and “Free users are limited to one custom connector” (Anthropic help).

The connector also reaches your phone. Per Anthropic, “Once you connect to a service on Claude or Claude Desktop, it will be available to use the next time you log in to your account on Claude for iOS or Android” (Use connectors to extend Claude’s capabilities). Installing connectors on mobile itself is still in beta, so add it on the web or desktop first. Use your laptop’s MCP servers from the Claude app on your phone covers what has to stay running.

Anthropic also runs its own MCP tunnels, but they are for organizations on the Enterprise plan, by request.

MCP Warp steps for Claude are in Connect Claude. MCP Warp isn’t certified by Anthropic; it’s built to work with Claude as a standard Streamable HTTP MCP client.

Claude Code

Claude Code runs on your machine and adds servers from the command line:

claude mcp add --transport http notes https://notes-anatoly.tunnel.mcpwarp.io/mcp

Then authenticate: run /mcp inside a Claude Code session and pick the server, or run claude mcp login notes from your shell. The general form is claude mcp add --transport http <name> <url>; the Claude Code MCP docs list the other options.

If Claude Code is your only client, you can point it at http://localhost:8765/mcp and skip the tunnel. The case for a public URL is that the same address then works in claude.ai, on your phone and in ChatGPT.

ChatGPT

Add a custom connector in ChatGPT’s settings and paste the URL, then complete the OAuth sign-in. Menu names move around as ChatGPT changes; look for “connectors”, “custom connectors”, “apps” or “MCP servers” in settings. Connect ChatGPT has the MCP Warp side.

Check your plan before you start. Custom connectors on ChatGPT Plus and Pro are reported to be limited to read and fetch actions, with full MCP (write actions) on Business, Enterprise and Edu. We couldn’t load OpenAI’s help article on developer mode to confirm this, so read it for your plan.

If ChatGPT is your only client, OpenAI’s Secure MCP Tunnel may be the simpler route. Its open-source client, openai/tunnel-client, connects “private or localhost MCP servers to ChatGPT, Codex, the Responses API, and AgentKit” and can spawn stdio servers. It doesn’t serve claude.ai or other clients. OpenAI’s announcement has the setup.

MCP Warp isn’t certified by OpenAI; it’s built to work with ChatGPT as a standard Streamable HTTP MCP client.

VS Code

Add the server to .vscode/mcp.json with "type": "http":

{
  "servers": {
    "notes": {
      "type": "http",
      "url": "https://notes-anatoly.tunnel.mcpwarp.io/mcp"
    }
  }
}

VS Code runs the OAuth sign-in when it first connects. Like Claude Code, it runs locally, so a localhost URL also works if you don’t need the server anywhere else. Connect other clients has the same snippet.

Anything else

Any client that speaks Streamable HTTP can use the URL: add a remote server pointing at it and complete the OAuth sign-in when the client asks. The legacy 2024-11-05 HTTP+SSE transport (a GET /sse endpoint plus POST /messages) is not supported by MCP Warp, so a client that only knows SSE won’t connect.

Comparison table

As of 9 October 2026. Cells marked “unverified” are ones we haven’t confirmed against the vendor’s documentation.

Client	Where to add it	Runs OAuth	Accepts localhost	Plan requirements
claude.ai	Customize > Connectors > Add custom connector	Yes	No	Free (1 custom connector), Pro, Max, Team, Enterprise
Claude Desktop	Connectors settings, same steps as claude.ai	Yes	No, for custom connectors	Same as claude.ai
Claude mobile apps	Add on web or desktop; it syncs	Uses the web grant (unverified)	No	Same as claude.ai
Claude Code	`claude mcp add --transport http`	Yes, via `/mcp` or `claude mcp login`	Yes	Unverified
ChatGPT	Settings, connectors or apps	Yes	No	Plus/Pro reported read-only (unverified)
VS Code	`.vscode/mcp.json`, `"type": "http"`	Yes	Yes	Unverified

The URL is tied to your MCP Warp account. Every request needs an OAuth token that belongs to the server’s owner, so other people can’t use your server through it even if they have the link. See Security.

When it doesn’t connect

Start with the status code at the URL. With MCP Warp, 503 means mcpwarp up isn’t connected, 404 means a wrong URL or a server disabled in the dashboard, and 429 means the month’s quota is used up. Troubleshooting lists every message.

If claude.ai says “Couldn’t reach the MCP server”, work through the checklist for that error. It applies to any server and any tunnel.