[BUG] API Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"messages.38.content.4.text: cache_control cannot be set for empty text blocks"},"request_id":"req_011CaBYDzZjcqizdjVBjSgZ4"}

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 yesterday, there has been a persistent error that prevents the use of the Windows app, causing every session to crash without any possibility of recovery. Every input is met with this API error.

API-Fehler
API Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"messages.38.content.4.text: cache_control cannot be set for empty text blocks"},"request_id":"req_011CaBYDzZjcqizdjVBjSgZ4"}

<img width="1252" height="727" alt="Image" src="https://github.com/user-attachments/assets/66ad1878-3471-425e-a520-333d0c77b281" />

What Should Happen?

Find Error in code and structure

Error Messages/Logs

API-Fehler
API Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"messages.38.content.4.text: cache_control cannot be set for empty text blocks"},"request_id":"req_011CaBYDzZjcqizdjVBjSgZ4"}

Steps to Reproduce

I open a new session because the previous one has crashed again. I enter a question or instruction, optionally upload an image for analysis, and every single time I receive an error message for every command.

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Version 1.3109.0 (35cbf6)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

<img width="1252" height="1359" alt="Image" src="https://github.com/user-attachments/assets/e8164fd0-a4c3-4162-9a66-81464381a265" />