[BUG] IS_SANDBOX=yes and port 27017 blocked on "Full" network access cloud environment

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?

On a cloud environment configured with Network Access set to "Full", IS_SANDBOX=yes is present in the environment and outbound TCP on port 27017 is blocked. This prevents the backend server from connecting to MongoDB Atlas.

What Should Happen?

A "Full" network access environment should allow all outbound TCP ports (including 27017) and should not behave like a sandbox environment.

Error Messages/Logs

echo $IS_SANDBOX → yes
timeout 5 bash -c "echo > /dev/tcp/89.192.9.15/27017" → 27017 BLOCKED
MongoClient.connect({ serverSelectionTimeoutMS: 8000 }) → FAILED: Server selection timed out after 8000 ms

Steps to Reproduce

1. Create a cloud environment on claude.ai/code with Network Access set to "Full"
2. Start a session
3. Run: echo $IS_SANDBOX
4. Run: timeout 5 bash -c "echo > /dev/tcp/<mongo-host>/27017" && echo "OPEN" || echo "BLOCKED"
5. Observe IS_SANDBOX=yes and port blocked despite Full network setting

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.145 (Claude Code)

Platform

Other

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Other

Additional Information

_No response_