### Check for existing issues

- [x] I have searched the existing issues and checked that my issue is not a duplicate.

### What happened?

Claude Code always gets API error in the new release, v1.83.10 and also v1.83.14. ```shell API Error: 400 {"error":{"message":"{\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"This model does not support effort level 'xhigh'. Supported levels: high, low, max, medium.\"},\"request_id\":\"req_011CahKFpUAzcJVuufFxtJyK\"}. Received Model Group=claude-opus-4.6\nAvailable Model Group Fallbacks=None","type":"None","param":"None","code":"400"}} ``` ```shell API Error: 400 {"error":{"message":"{\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"adaptive thinking is not supported on this model\"},\"request_id\":\"req_011CahftyYjeUQQMbHbZ5QtJ\"}. Received Model Group=claude-haiku-4.5\nAvailable Model Group Fallbacks=None","type":"None","param":"None","code":"400"}} ``` After an investigation, it seems that for supporting opus-4.7, the newly introduced function, _translate_legacy_thinking_for_adaptive_model, in litellm/llms/anthropic/experimental_pass_through/mess…