Docs

Claude (web / desktop / mobile)

1. Open Settings → Connectors → Add custom connector
2. Paste the connector URL above and click Add
3. Complete the OAuth login (email one-time code) and authorize
4. In a new chat open + → Connectors → Tool access → choose Loaded tools; Claude has no direct link to this setting, and future chats will then default to loading One
5. Now ask Claude to query data, search or call models right in the chat

ChatGPT (Pro / Business / Enterprise)

1. Settings → Apps → Advanced → enable Developer mode
2. Add a connector, paste the connector URL, choose OAuth
3. Sign in, authorize, and use it in any conversation

Note: free ChatGPT doesn't support custom connectors yet (an OpenAI platform limitation).

Claude Code

The first tool call opens a browser for the OAuth login. An API key works too:

Codex CLI

Cursor / Windsurf / other MCP clients

Add this to mcp.json:

{
  "mcpServers": {
    "justone": {
      "url": "https://justoneconnector.com/api/mcp"
    }
  }
}

Agent frameworks / scripts (API key)

Create an API key in the dashboard and send it in the request header — no OAuth needed:

POST https://justoneconnector.com/api/mcp
Authorization: Bearer jc_sk_xxxxxxxx
Content-Type: application/json
Accept: application/json, text/event-stream

{"jsonrpc":"2.0","id":1,"method":"tools/list"}

The OpenAI Agents SDK, Vercel AI SDK and LangChain all mount remote MCP servers with this config.