[BUG] Invalid agent configuration generated

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?

Same as the following issue:
https://github.com/anthropics/claude-code/issues/6019

Fix was mentioned by user on #6019: needed to relogin using /login. Worked immediately after this.

I spent almost a half hour trying to figure out the cryptic error that had no additional information or recent reports.

Reporting this so devs know the bug is still present, ambiguous, and wasting peoples' time.

What Should Happen?

Claude should generate subagent from description. If an error occurs, it should include description of the actual underlying cause, not just a symptomatic error.

Error Messages/Logs

Invalid agent configuration generated

Steps to Reproduce

Run claude
Use /agents
Attempt to create new subagent
Select recommended option of Claude generating based off a description

Claude Model

Opus

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.1.119

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Other

Additional Information

_No response_