[BUG] MCP URL must be parsable

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

I can't authenticate with a remote mcp server.

    "groundcover2": {
      "type": "http",
      "url": "https://mcp.groundcover.com/api/mcp",
      "headers": {
        "X-Timezone": "America/Chicago",
        "X-Tenant-UUID": "b620cbde-2750-4d10-aa9e-67554c700c3b",
        "X-Backend-Id": "groundcover"
      }
    }

What Should Happen?

I should be able to authenticate with the remote mcp server.

Error Messages/Logs

│ Groundcover2 MCP Server                                                                                                                                                   │
│                                                                                                                                                                           │
│ Status: ✘ failed                                                                                                                                                          │
│ URL: https://mcp.groundcover.com/api/mcp                                                                                                                                  │
│ Config location: /Users/paymahn/.claude.json                                                                                                                              │
│                                                                                                                                                                           │
│ Error: [                                                                                                                                                                  │
│   {                                                                                                                                                                       │
│     "validation": "url",                                                                                                                                                  │
│     "code": "invalid_string",                                                                                                                                             │
│     "message": "Invalid url",                                                                                                                                             │
│     "path": [                                                                                                                                                             │
│       "client_uri"                                                                                                                                                        │
│     ]                                                                                                                                                                     │
│   },                                                                                                                                                                      │
│   {                                                                                                                                                                       │
│     "code": "custom",                                                                                                                                                     │
│     "message": "URL must be parseable",                                                                                                                                   │
│     "fatal": true,                                                                                                                                                        │
│     "path": [                                                                                                                                                             │
│       "client_uri"                                                                                                                                                        │
│     ]                                                                                                                                                                     │
│   }                                                                                                                                                                       │
│ ]                                                                                                                                                                         │
│                                                                                                                                                                           │
│ ❯ 1. Authenticate                                                                                                                                                         │
│   2. Reconnect                                                                                                                                                            │
╰───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯
   Esc to go back

Steps to Reproduce

1. make a groundcover account (it's not free)
2. set up the mcp
3. try to auth

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

1.0.124 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

iTerm2

Additional Information

_No response_