[BUG] Subagents don't return an Agent ID when they're interrupted

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?

Sometimes a subagent goes on for a very long time, and I either need to stop the session or give some more info.

So I have to exit or press escape. Hoping I could resume it later.

But as Claude told me itself:

● You're right, I apologize. That agent did extensive work before being interrupted. Unfortunately when a task is interrupted, I don't receive the agent ID to resume it. Let me check if there's any output file or way to recover its findings:

What Should Happen?

Subagents should always be resumable. Doesn't matter if they decided to end their own session or if I did.

Error Messages/Logs

Steps to Reproduce

1. Start a subagent
2. Press escape
3. Ask claude to resume
4. Failure

Claude Model

Opus

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.1.4

Platform

Anthropic API

Operating System

Other Linux

Terminal/Shell

Other

Additional Information

_No response_