Cardzen with Claude Code and the Claude API

Claude Code and apps built with the Claude API can use Cardzen through MCP. These are developer clients. The Cardzen tools you can use depend on your plan and the permissions you approve.

Claude Code

1. Add Cardzen in your terminal:

   claude mcp add --transport http cardzen https://mcp.cardzen.ai/mcp
   

2. Start Claude Code with claude.

3. Enter /mcp, select Cardzen, and complete Cardzen sign-in and permission approval in your browser.

4. Try asking: “Which of my cards should I use for groceries?”

Claude Code handles the browser authorization flow. You do not need a Cardzen API key or a manually configured bearer token. See Claude Code's MCP documentation for more about its MCP commands.

Claude API

Anthropic's MCP connector lets a Messages API request use Cardzen tools. Your application must obtain a Cardzen OAuth user access token through a separate authorization flow, store it securely, and refresh it as needed. Do not put a real token in public code or documentation.

Send the HTTP header anthropic-beta: mcp-client-2025-11-20. Add this JSON fragment to your Messages API request:

{
  "mcp_servers": [
    {
      "type": "url",
      "url": "https://mcp.cardzen.ai/mcp",
      "name": "cardzen",
      "authorization_token": "YOUR_CARDZEN_ACCESS_TOKEN"
    }
  ],
  "tools": [
    {
      "type": "mcp_toolset",
      "mcp_server_name": "cardzen"
    }
  ]
}

This is a fragment, not a complete request. Supply model, max_tokens, and messages, and authenticate separately with the Anthropic API. See Anthropic's MCP connector documentation for the full API requirements.

For Claude's standard connector, see Set Up Cardzen in Claude. Review MCP Privacy and Security and MCP Limits and Troubleshooting for access and connection details.