Put an MCP server online

An MCP server on localhost works for AI tools on the same computer. claude.ai, ChatGPT and a teammate's Claude Code connect from elsewhere: claude.ai, for example, connects from Anthropic's cloud, not from your computer, so the server needs a public HTTPS address. In this tutorial you put a local MCP server online at https://mcp.yourhost.com/mcp, connect claude.ai to it, and see who's connected.

You need: Teitunnel, a Cloudflare account with a domain (first route), and an MCP server that speaks Streamable HTTP or SSE, here on port 8000.

1. Share it

teitunnel share 8000 --mcp --on mcp.yourhost.com

Teitunnel first checks that port 8000 answers MCP (at /mcp, then /sse, then /; set another path with --mcp-path). Then it shares it with streams kept alive, requires a bearer token, and prints ready configurations for Claude Code, Cursor and VS Code.

The token is kept in your system's keychain for that hostname, so clients keep working the next time you share on it. teitunnel token mcp.yourhost.com shows it again, and --new-token makes a new one.

An AI agent can do the same with the expose_mcp_server tool of Teitunnel's own MCP server; the agent never sees the token.

2. Connect claude.ai

In claude.ai, Customize ▸ Connectors, then +. Give it a name and the URL https://mcp.yourhost.com/mcp, and click Add. (On Claude's free plan you can add one custom connector.)

claude.ai can't use a fixed token, so it signs in with OAuth:

1. The browser shows a short code and waits.
2. Teitunnel shows a dialog with the same code and the app's name, asking whether it may connect. When the app isn't running, teitunnel share asks in the terminal instead.
3. Check that the codes match, and allow it.

ChatGPT and other clients that support remote MCP servers sign in the same way.

3. Connect Claude Code, Cursor or VS Code

These accept a URL and a header, so they use the bearer token. Paste the configuration teitunnel share printed, for example on another computer. The token is in it, so share it only with people who should use the server.

4. See who's connected

Approved OAuth connections are listed in AI & Integrations ▸ Shared Servers. Disconnect stops one at once. Their tokens are for this server only, last an hour and renew themselves; Teitunnel keeps only their hashes.

Every request goes through the inspector, so you can see each tool call a client makes and replay it.

Keep it online

The share lasts as long as the command runs. Share on the same hostname again and clients reconnect with the same token or sign-in.

Troubleshooting

• "No MCP server answered at …": the server isn't running on that port, or its endpoint is elsewhere: pass --mcp-path /your/path.
• The client says it's unauthorized: a client with a fixed token needs the current one (teitunnel token mcp.yourhost.com). After --new-token, update every client.
• Your server has its own sign-in: it keeps it. Teitunnel adds OAuth only in front of servers that don't ask for credentials themselves.

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