[BUG] Claude DEEP RESEARCH STUCKS

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?

Claude Deep Research stucks. Its researching for hours and then just a error message appears that says something went wrong or it creates the report with the only output "test".

<img width="3829" height="1832" alt="Image" src="https://github.com/user-attachments/assets/3c5e9079-3d4f-46d1-b14a-2aab346451d2" />

<img width="3840" height="2064" alt="Image" src="https://github.com/user-attachments/assets/6449c2b2-d892-4e14-bf95-09aa8b8c35ee" />
<img width="2221" height="1288" alt="Image" src="https://github.com/user-attachments/assets/6d80c59f-cea3-4d7f-8c1e-1937c64a65e8" />
<img width="3713" height="1813" alt="Image" src="https://github.com/user-attachments/assets/c3567991-2c68-469e-a409-97d0ebeec906" />

What Should Happen?

I have done hundreds of deep researches with Claude and it always takes only a few minutes, max 15-20, not more. But today and yesterday it just doesn't work. I tried many times, different Claude accounts but nothing worked.

Error Messages/Logs

Something went wrong or ONLY "test" in the Research Report. See screenshots...

Steps to Reproduce

Just deep research

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.76

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Other

Additional Information

_No response_