Connect an assistant

Connecting takes one URL. There is no API key to create, copy or paste: the assistant sends you to a Sign Customiser consent screen, you choose the store and approve the permissions it asked for, and the connection appears in your admin where you can watch it and disconnect it.

The endpoint is the same for every client:

https://web.signcustomiser.com/mcp

What happens when you connect

1. The client fetches https://web.signcustomiser.com/.well-known/oauth-protected-resource/mcp and learns which authorization server protects the endpoint.
2. If it has never connected before, it registers itself. No secret is issued, and a self-registered client is marked as unverified on the consent screen.
3. Your browser opens the Sign Customiser consent screen. Sign in if you are not already.
4. Choose the store the assistant will act for. A connection is bound to one store for its whole life. To connect a second store, connect the client again and pick the other one.
5. Approve the permissions. They are listed in plain language, for example View customisers and Manage pricing. Approve only what you want the assistant to do; a tool whose permission you declined answers with the name of the permission it needs rather than failing silently.
6. You are returned to the client, which can now call tools.

Nothing about this flow is client-specific. If your client supports remote MCP servers with OAuth, the URL above is all it needs.

Claude

Claude on the web and Claude Desktop. Open Settings > Connectors > Add custom connector, name it Sign Customiser, and paste the endpoint URL. Claude opens the consent screen in your browser.

Claude Code. Add it from the command line:

claude mcp add --transport http sign-customiser https://web.signcustomiser.com/mcp

Then run /mcp inside Claude Code and choose Authenticate to complete the browser consent step.

ChatGPT and Codex

ChatGPT connectors. In Settings > Connectors, add a custom connector with the endpoint URL. Developer mode is required while a connector is unlisted.

Codex. Add the server to ~/.codex/config.toml:

[mcp_servers.sign_customiser]
url = "https://web.signcustomiser.com/mcp"

Codex opens the consent screen on first use.

Cursor and other mcp.json clients

Most editors and libraries read the same shape. In Cursor, that is .cursor/mcp.json in the project or ~/.cursor/mcp.json globally:

{
  "mcpServers": {
    "sign-customiser": {
      "url": "https://web.signcustomiser.com/mcp"
    }
  }
}

Clients that require the transport to be named explicitly take "type": "http" beside the URL.

MCP Inspector

The Inspector is the fastest way to see the raw wire traffic while building an integration.

npx @modelcontextprotocol/inspector

Connect to the endpoint with transport Streamable HTTP. Leave protocolEra at its default of legacy. The Sign Customiser endpoint answers the initialize family of revisions (2025-11-25, 2025-06-18, 2025-03-26 and 2024-11-05) and does not answer the 2026-07-28 server/discover family, so a run configured with protocolEra: modern fails to negotiate by design. Always record which era a result came from; “Inspector connects” on its own says nothing.

Which permissions to approve

Approve the smallest set that covers what you want to do. The scopes are listed in full on the MCP server overview, and each tool’s reference page names the one it needs.

A useful starting set for read-only exploration is View store details, View customisers and View pricing. Add Manage customisers or Manage pricing only when you want the assistant to change your storefront.

Use advanced tools (mcp:advanced) is different from the rest. It grants no data on its own. It makes the advanced catalogue visible, and every operation there still needs the matching permission above. Leave it unapproved unless you need an operation the curated tools do not cover.

Watching and disconnecting

Open Tools & Settings > MCP server in your Sign Customiser admin. It lists every connected assistant with the permissions it holds, when it last called, and a Revoke button. The same page shows how many calls each tool made and every change a connection has written.

Revoking is immediate and does not need the client’s cooperation.

When something does not connect

• The client asks for an API key. It does not support remote MCP over OAuth. A Sign Customiser API key is a different credential for a different surface, and the MCP endpoint does not accept one.
• A tool answers insufficient_scope. The connection was approved without the permission that tool needs. Reconnect the client and approve the scope it names.
• A tool the documentation lists is missing from the client’s tool list. It is one of the five advanced tools, and the connection was not granted mcp:advanced.
• Everything answers 401. The connection expired or was revoked. Reconnect from the client.