infrastructure-unsupported-params-d-when-using-a-non-anthropic-model-provider-e-g-verc-b91d0a2f

THEN Set 'litellm.drop_params=true' in your proxy configuration to automatically drop unsupported parameters like 'thinking'. Alternatively, allow the 'thinking' parameter dynamically by sending 'allowed_openai_params': ['thinking'] in your request.

In proxy config:
litellm_settings:
  drop_params: true

Or in request:
{
  "model": "vercel_ai_gateway/anthropic/claude-sonnet-4.5",
  "allowed_openai_params": ["thinking"]
}