[BUG] Claude code fails when sharing image only

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 am using claude code in windows app to build websites via github and vercel. At a certain point I only shared a screenshot (no text) after a long session. The session became unusable after that with API Error: 400 messages: text content blocks must be non-empty. Even if I tried just simple hello messages, it wont allow me to do anything in that session.

What Should Happen?

It should have thrown an error and told me not to paste just screenshot.

Error Messages/Logs

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

Steps to Reproduce

Try pasting just screenshot in a long ongoing claude code sesson

Claude Model

Opus

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

latest

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Other

Additional Information

just using code under claude code session