claude-code - 💡(How to fix) Fix [BUG] Keep getting context management extra inputs are not permitted [1 participants]

API Error: 400 {"error":{"message":"{"message":"context_management: Extra inputs are not permitted"}No fallback model group found for original
model_group=claude-sonnet-4-6. Fallbacks=[{'gpt-5.2': ['gpt-5.2-chat']}]. Received Model Group=claude-sonnet-4-6\nAvailable Model Group Fallbacks=None\nError doing the
fallback: {"message":"context_management: Extra inputs are not permitted"}","type":"None","param":"None","code":"400"}}

TL;DR

• The issue might be resolved by checking and handling extra inputs in the context management of the Claude Code API requests.

Guidance

• Review the API request payload to ensure it only includes permitted inputs, as the error message suggests extra inputs are not allowed.
• Verify that the /clear command is correctly implemented and effectively resets the context, as the issue persists even after running this command.
• Investigate the fallback model group configuration to ensure it is correctly set up for the claude-sonnet-4-6 model, as the error message mentions a lack of fallback model groups.
• Check the Anthropic API documentation for any recent changes to input validation or context management that might be causing this issue.

Example

• No specific code snippet can be provided without more context, but reviewing the API request payload and fallback model group configuration is a good starting point.

Notes

• The issue is reported as a regression, suggesting that a previous version of the Claude Code or Anthropic API worked correctly, which might indicate a change in the API or its validation rules.
• Without knowing the last working version, it's challenging to pinpoint the exact change causing the issue.

Recommendation

• Apply workaround: Given the information provided, applying a workaround such as checking and handling extra inputs seems more feasible than upgrading to a fixed version, as the issue's root cause is not clearly identified as a version-specific problem.