[BUG] Connection lost mid-response since Aug 9-10, persists after update to 2.1.227 and model switch

Preflight Checklist

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

What's Wrong?

Since around August 9-10, 2026, I've been getting frequent "Connection lost mid-response" errors during Claude Code sessions. The response stream cuts off unexpectedly mid-generation.

This started happening after a period of normal use, and has persisted even after:

• Updating to version 2.1.227
• Switching the active model to Sonnet

Since it occurs across different models and after updating, it doesn't seem tied to a specific model or to being on an outdated client version.

What Should Happen?

The response stream should complete normally without dropping mid-generation.

Error Messages/Logs

API Error: Connection lost mid-response. The response above may be incomplete.

Steps to Reproduce

1. Start a normal Claude Code session (claude in terminal or VSCode extension)
2. Work through a multi-turn conversation involving tool calls / longer responses
3. At some point during a response, the stream cuts off with "Connection lost mid-response"
4. This happens frequently — multiple times per session

Note: Not tied to a specific file or command that I've been able to isolate. Started around Aug 9-10, 2026. Persists after updating to 2.1.227 and after switching the active model to Sonnet, so it doesn't appear to be model- or version-specific.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.227

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_