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Short Answer

If Claude Code returns 400 ValidationException, Extra inputs are not permitted, or an error related to cache_control.scope on the AWS Claude official route, set CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS=1 before starting Claude Code. This disables Claude Code experimental beta request fields so unsupported extra fields are not rejected by the AWS Claude / Bedrock route. Use export for a quick test, then put the setting in ~/.claude/settings.json for persistent use.

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When This Applies

  • Claude Code is already configured with LaoZhang API
  • The request uses the AWS Claude official route or a Bedrock-related route
  • The terminal or request log shows 400 ValidationException
  • The error contains Extra inputs are not permitted
  • The error points to cache_control.scope, cache_control, scope, or another extra request field
  • The API key, balance, and model ID look correct, but Claude Code is rejected before a normal model response
This error is usually a request-field compatibility issue. It does not automatically mean the account balance, model permission, or API key is wrong. Disable experimental beta request fields before rotating keys.

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Steps To Fix

1

Stop the current Claude Code process

If Claude Code is already running, exit it first. The environment variable must be present before Claude Code starts.
2

Export the compatibility setting

Run this in the same terminal where you will start Claude Code:
export CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS=1
3

Start Claude Code again

Start Claude Code from the same terminal:
claude
If the 400 error disappears, the issue was likely caused by Claude Code experimental beta fields being rejected by the AWS Claude / Bedrock route.

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Persistent settings.json Configuration

To avoid setting the variable every time, add it to ~/.claude/settings.json: 
{
  "env": {
    "CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS": "1"
  }
}
If ~/.claude/settings.json already contains your LaoZhang API base URL, token, and model, merge the new key into the existing env object instead of replacing the file: 
{
  "env": {
    "ANTHROPIC_BASE_URL": "https://api.laozhang.ai",
    "ANTHROPIC_AUTH_TOKEN": "sk-your-laozhang-api-key",
    "ANTHROPIC_MODEL": "claude-sonnet-4-6",
    "CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS": "1"
  }
}
Do not share screenshots that expose the full ANTHROPIC_AUTH_TOKEN, API key, or AccessToken. If support needs the configuration, send a masked version plus the full error text.

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Why This Fix Works

Some Claude Code versions may add experimental beta fields to the request body. The AWS Claude official route or Bedrock-related route may strictly validate the payload and reject unsupported fields with errors such as:
  • 400 ValidationException
  • Extra inputs are not permitted
  • Errors related to cache_control.scope
CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS=1 tells Claude Code not to send those experimental beta request fields, making the request shape closer to what the route accepts. This setting fixes field compatibility only; it does not replace checks for model access, balance, API key validity, or model ID correctness.

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If The Error Continues

  1. Restart the terminal or restart Claude Code after changing the setting.
  2. Check that CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS is under the top-level env object in ~/.claude/settings.json.
  3. Update Claude Code to the current available version and retry.
  4. Confirm that the model ID is still available in the console.
  5. Make sure you are using a LaoZhang API key and a token group that works with Claude Code.
  6. Check usage logs to see whether the failure is request validation, model access, or balance related.

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Still Need Help

If disabling experimental beta fields does not fix the issue, send support:
  • Account email or username
  • Claude Code version
  • Operating system and terminal type
  • Model ID
  • Whether the AWS Claude official route is being used
  • Full error text, especially the field name after ValidationException
  • Request time, status, and Request ID from LaoZhang API usage logs
  • A masked ~/.claude/settings.json, without the full API key or AccessToken