claude-code - 💡(How to fix) Fix [BUG] claude code prefilling assistant messages when using claude model 4.6+ [1 participants]

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anthropics/claude-code#52433Fetched 2026-04-24 06:07:23
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Error Message

Error Messages/Logs

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Preflight Checklist

  • I have searched existing issues and this hasn't been reported yet
  • This is a single bug report (please file separate reports for different bugs)
  • I am using the latest version of Claude Code

What's Wrong?

使用claude code时,用claude opus或sonnet 4.6及以上模型时报错This model does not support assistant message prefill. The conversation must end with a user message。经过初步排查,cc初始时出现此问题可通过/clear解决,说明是会话问题 ,而会话中出现此问题推测是由于网络问题导致api的response没能一次性返回,而cc不会补全对话,所以触发了prefill特性。

What Should Happen?

应当给出提示并自动补全被中断的会话

Error Messages/Logs

Steps to Reproduce

切换任一claude opus或sonnet 4.6及以上模型,在模型给出回复时配置网络模拟api无法一次性返回response遇到中断的情况。

Claude Model

Other

Is this a regression?

Yes, this worked in a previous version

Last Working Version

No response

Claude Code Version

v2.1.118

Platform

Other

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Terminal.app (macOS)

Additional Information

No response

extent analysis

TL;DR

The issue can be potentially resolved by ensuring the API response is returned in a single chunk to prevent the conversation from being interrupted.

Guidance

  • Verify the network configuration to ensure it can handle the API response without interruptions.
  • Check the Claude Code version (currently v2.1.118) for any known issues related to API response handling.
  • Test the model with a stable network connection to see if the issue persists.
  • Consider implementing a retry mechanism or a more robust error handling system to handle cases where the API response is interrupted.

Example

No code snippet is provided as the issue does not contain sufficient information about the specific code implementation.

Notes

The issue seems to be related to the network connection and the way the API response is handled. However, without more information about the code and the specific error messages, it's difficult to provide a more detailed solution.

Recommendation

Apply workaround: Implement a retry mechanism or a more robust error handling system to handle cases where the API response is interrupted, as the root cause of the issue seems to be related to network interruptions rather than a specific version issue.

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