[BUG] Please finally fix the JSON low surrogate issue.

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?

After a certain context length, the context crashes with every message being responded to like this:

<img width="1098" height="717" alt="Image" src="https://github.com/user-attachments/assets/af72bce3-36e6-47f8-963c-0a1013fcb7dd" />

Other issues blame this on plugins, but I know for a fact it is because of heavy use of emoji in a Telegram chat this bot is used in.

What Should Happen?

Claude Code should just keep working. If it gets this error back, it should fix errors with the JSON by itself. A restart of the complete CC harness will fix this, but that is hardly acceptable.

Error Messages/Logs

API Error: 400 The request body is not valid JSON: no low surrogate in string: line 1 column 1261392 (char 1261391)

Steps to Reproduce

The issue has been demonstrated and reproduced in other GitHub issues multiple times, where the usual guidance is to 'reduce plugins with emoji'. In this context, the problem is not plugins, it is the input itself.

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

latest

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Windows Terminal

Additional Information

_No response_