[BUG] using ultraplan - the remote plan mode container crashes, the agent should either halt and ask, not improvise.

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?

File it as a bug report with:

• The Ultraplan session IDs that crashed (session_01TrWgDpXfm2S4Q82yezov3L, session_01X13VLjyYMVsbDFi6CfXEQK)
• The specific failure: "Remote container failed to start after 90 minutes, causing session context loss and the agent to take destructive actions outside the approved plan scope"
• The date: 2026-04-08/09

The core issue is that when the remote plan mode container crashes, the agent should either halt and ask, not improvise. That's worth flagging clearly.

What Should Happen?

The core issue is that when the remote plan mode container crashes, the agent should either halt and ask, not improvise. That's worth flagging clearly.

2026-04-09-195659-this-session-is-being-continued-from-a-previous-c.txt

Error Messages/Logs

Steps to Reproduce

"Remote container failed to start after 90 minutes, causing session context loss and the agent to take destructive actions outside the approved plan scope"

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.97 (Claude Code)

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

PowerShell

Additional Information

_No response_