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Your URL

Every account gets a reserved slug — two words, minted at first sign-in, and yours permanently:
It does not change between runs. That is the point: a connector you add to Claude.ai today still works tomorrow morning, and next week. You are not re-pasting a fresh random URL into six clients every time you restart. You can see yours on your profile page, or with heymcp whoami.

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The three shapes

See Custom domains for the DNS side.

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Slug rules

A slug is a DNS label, so:
  • 3 to 63 characters
  • lowercase letters, digits and hyphens only
  • no leading or trailing hyphen
  • no double hyphen anywhere (-- is reserved by IDNA for punycode)
  • not one of the reserved names — admin, api, app, docs, edge, inspector, oauth, relay, www and about thirty others that either already mean something on the domain or would let one account impersonate HeyMCP itself
If you ask for a slug that’s taken or invalid, the CLI tells you which, and your reserved slug still works.

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What is shared

By default a tunnel forwards only the MCP route and well-known metadata: Anything containing .. is always refused, whatever your settings. This is deliberate. It keeps a HeyMCP tunnel from becoming free web hosting, and there is no cost to you: agents can’t click through an interstitial or browse your dev site anyway.

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Why /.well-known/* is open

So that your own OAuth works. If your MCP server publishes /.well-known/oauth-protected-resource or /.well-known/oauth-authorization-server, clients discover it through the tunnel exactly as they would against a directly-hosted server. HeyMCP itself is not an authorization server — see Authentication.

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Sharing everything

Now every path is forwarded. Useful when your MCP server shares a host with a health check, a docs page, or an auth flow you need reachable.
--all-paths makes your entire local server publicly reachable to anyone who knows the URL. Pair it with --bearer unless you genuinely mean “public”.

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A non-default MCP route

If your server serves MCP somewhere other than /mcp:
--path currently needs --all-paths alongside it. The default path policy only forwards /mcp* and /.well-known/*, and --path does not widen it — so --path /api/mcp on its own advertises a URL that answers -32003. Passing --all-paths is the workaround today.
Alongside the public URL, the CLI prints a short link:
That’s the live timeline for this session. It’s private to your account — a session belongs to exactly one user and nobody else can subscribe to it.