[BUG] Sandbox setting silently ignored on missing dependencies

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?

When configured explicitly to start in sandbox mode when socat is not installed, claude starts in normal mode, instead.

What Should Happen?

Claude should fail to start since it cannot enter sandbox mode, as required by the configuration.

Error Messages/Logs

N/a

Steps to Reproduce

On a Linux host:

1. Ensure that the socat utility is not installed (e.g. on Ubuntu, use sudo apt remove socat).
2. Create a file called settings.json with: {"sandbox": {"enabled":true}}.
3. Run clade with claude --permission-mode acceptEdits --verbose --settings ./settings.json
4. Check if sandbox mode is enabled with /sandbox, which shows the current state before hitting return.

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.0.54 (Claude Code)

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

iTerm2

Additional Information

Given users can reasonably expect claude to obey such an explicit setting, I believe that this is a significant security problem, as the same users may have configured permissions for claude that are too risky without sandboxing.