[BUG] `claude mcp` subcommand quirks

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?

1. claude mcp list -- With an an invalid settings.json file, claude mcp list reports "no MCP servers configured".
2. claude mcp add -- Not possible to add an env value which is itself an env var (as supported in .mcp.json

What Should Happen?

1. claude mcp list should exit with the same error as claude itself: "Invalid or malformed JSON`.

1. claude mcp add -e KEY=VALUE should tolerate VALUE being the notation of env vars in .mcp.json: ${FOO}

Should generate (manually added env value):

{
  "mcpServers": {
    "tailwindplus": {
      "type": "stdio",
      "command": "uv",
      "args": [
        "--directory",
        "/Users/rmichael/Documents/Personal/Source/mcp-tailwindplus/dependencies",
        "run",
        "mcp-tailwindplus"
      ],
      "env": {
        "MCP_TAILWINDPLUS_DATA": "${MCP_TAILWINDPLUS_DATA}"
      }
    }
  }
}

Error Messages/Logs

1.


 $ claude mcp list
No MCP servers configured. Use `claude mcp add` to add a server.
 $ claude
──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
 Settings Error

 /Users/rmichael/Documents/Personal/Source/mcp-tailwindplus/development/.claude/settings.json
  └ Invalid or malformed JSON


2.


 $ claude mcp add -s project tailwindplus -- uv --directory $( readlink -fn ../../mcp-tailwindplus/dependencies ) run mcp-tailwindplus
Invalid environment variable format: tailwindplus, environment variables should be added as: -e KEY1=value1 -e KEY2=value2


See above for correct `mcp.json`

Steps to Reproduce

1. claude mcp list
2. claude mcp add -e FOO='${FOO}' foo -- uv run foo

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.5 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Other

Additional Information

_No response_