[BUG] messages.170.content.1.text: cache_control cannot be set for empty text blocks

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?

I keep get error messages and cant keep use sessions.

What Should Happen?

Should be able to just attach screenshot without text.

Error Messages/Logs

API Error
API Error: 400 messages.170.content.1.text: cache_control cannot be set for empty text blocks
Vad ska jag välja här

API Error
API Error: 400 messages: text content blocks must be non-empty
vilken ska jag välja i dropmenyn?

API Error
API Error: 400 messages: text content blocks must be non-empty

Steps to Reproduce

1. attach screenshot without text

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

dont know

Claude Code Version

2.1.146 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

<img width="1380" height="712" alt="Image" src="https://github.com/user-attachments/assets/8b2749a8-0d6a-4433-bb18-4eaa80acce75" />