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Do not use --bearer with Claude.ai. The custom connector dialog has no field for a static token, so a tunnel that requires one will fail — and Claude.ai fails silently. Share without it:

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Add the connector

1

Open your connectors

In Claude, open Settings, then Connectors under the Customize heading in the left column.
2

Add → Add custom connector

The Add dropdown is at the top right of the connectors panel.
The Add dropdown in Claude's connectors panel, showing Browse connectors and Add custom connector

Settings → Connectors → Add → Add custom connector

3

Fill in the dialog

Leave Advanced settings alone. Those two fields are an OAuth Client ID and Secret, which a HeyMCP tunnel doesn’t use — see Authentication.
Claude's Add custom connector dialog with a name and a HeyMCP tunnel URL filled in

The custom connector dialog, filled in with a HeyMCP tunnel URL

4

Add

Claude connects, discovers your tools, and the connector appears in the list marked Custom.
Watch your HeyMCP inspector while you do this. You should see INIT, NOTIF and LIST rows appear within a second or two, fingerprinted as Claude.ai. If nothing appears, the request never reached your tunnel and the problem is the URL, not your server.

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Plan requirements

On Team and Enterprise, the owner hovers Custom and picks Web when adding. Members see the connector labelled “Custom” and click Connect.

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Claude reaches you from Anthropic’s cloud

The connector is fetched by Anthropic’s infrastructure, not by your browser. Two things follow:
  • Your tunnel must be running. A URL that works in your browser because something is cached will not work for Claude.
  • Claude.ai is not subject to browser CORS on the MCP route.

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Try it

Start a conversation and ask Claude to use one of your tools. The CALL row appears in the inspector as it happens, with the arguments Claude chose. This is where the classic finding shows up: ask for something with a time in it and watch Claude send "7pm" for a parameter with no format constraint. schema/no-format

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It’s not showing up

Claude.ai is the least forgiving client to debug because it says nothing at all. Work through this in order — it’s ordered by how often each one is the answer.
Before touching Claude, look at the Handshake tab in your inspector, or run heymcp probe localhost:8000.Two findings block Claude.ai completely and are invisible from your side:
  • transport/content-type — your MCP route answers with something other than application/json or text/event-stream. This is the single most common cause of a connector that silently never works.
  • transport/accept-sse — your server rejects Accept: text/event-stream.
Claude never reached the edge. Check the URL character by character, confirm it ends in /mcp, and confirm heymcp share is still running in your terminal.
Your server accepted initialize and then something went wrong. Expand the INIT← row in the inspector to see exactly what it answered. An OPAQUE row here usually means an HTML error page where JSON was expected.
Claude can see them and is choosing not to use them. Check the handshake report for tool/no-description and tools/description-length — Claude.ai caps descriptions at about 1024 characters and will truncate or drop anything longer.
Claude.ai can’t send one. Restart the tunnel without it.
When a tool works in Claude Code and not in Claude.ai, the difference is almost always a limit: Claude Code accepts ~8192-character descriptions and 128-character names, Claude.ai accepts ~1024 and 64.