[BUG] claude -p handles beta flags differently than without -p

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?

claude is working when invoked in interactive mode via litellm with settings.json:

{
  "env": {
    "ANTHROPIC_BASE_URL": "https://litellm.ccri.com",
    "ANTHROPIC_AUTH_TOKEN": "sk-myomy-actualtoken",
    "ANTHROPIC_DEFAULT_SONNET_MODEL": "litellm-fips-sonnet-4-5",
    "ANTHROPIC_DEFAULT_HAIKU_MODEL": "litellm-fips-sonnet-4-5",
    "CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC": "1"
  },
  "permissions": {
    "allow": [
      "Bash(find *)",
      "Bash(ls *)"
    ],
    "deny": [
      "WebSearch",
      "WebFetch"
    ]
  }
}

but fails with API Error: 400 {"error":{"message":"{\"message\":\"invalid beta flag\"}. Received Model Group=litellm-fips-sonnet-4-5\nAvailable Model Group Fallbacks=None","type":"None","param":"None","code":"400"}} when invoked with the -p / --print flag.

What Should Happen?

claude and claude -p should handle experimental beta flags the same way.

Error Messages/Logs

claude -p "some prompt"

produces:

`API Error: 400 {"error":{"message":"{\"message\":\"invalid beta flag\"}. Received Model Group=litellm-fips-sonnet-4-5\nAvailable Model Group Fallbacks=None","type":"None","param":"None","code":"400"}}`

Steps to Reproduce

Set up connection via litellm.

Make sure ANTHROPIC_AUTH_TOKEN is NOT set as an environment variable or the shell invoking claude.

Run claude -p "some prompt", observe that settings from ~/.claude/settings.json do not get used.

If ANTHROPIC_AUTH_TOKEN is set, then the settings from ~/.claude/settings.json do get loaded, and claude -p "some prompt" does work.

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.31

Platform

AWS Bedrock

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Other

Additional Information

_No response_