[BUG] Cowork — "Additional allowed domains" allowlist non-functional

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?

Description:
The "Additional allowed domains" field under Organization Settings → Capabilities → Code execution with "Domain allowlist" set to "Package managers only" appears to have no effect. All custom domain entries are silently ignored by the sandbox proxy. Network egress to allowed domains is

What we tried:
Added every variation: *.docs.google.com, docs.google.com, *.google.com, google.com — none worked
Started fresh Cowork sessions after each change
"Allow all domains" works correctly (immediately after setting and restarting Claude Cowork, so it's also not a caching issue), confirming the infrastructure is fine

_Working:_
curl https://pypi.org/ → 200
curl https://github.com/ → 200

_Blocked (403 from proxy / no response):_
curl https://docs.google.com/ → blocked
curl https://google.com/ → blocked
curl https://www.google.com/ → blocked

Again, all of these blocked curls work as soon as "All domains" are allowed, so it's not an infra issue.

Conclusion:
The "Package managers only + additional domains" mode works for the baseline, but custom entries added via the UI are never applied. The field appears broken.

What Should Happen?

Network egress is allowed to allowed domains in whitelist

Error Messages/Logs

Steps to Reproduce

1. In Admin Settings → Capabilities → Code execution, set domain allowlist to "Package managers only" and add one or more custom domains (e.g. google.com, *.google.com, docs.google.com)
2. Start a new Cowork session
3. Run the following curl commands:

These work (package manager baseline):
curl https://pypi.org/       # → 200
curl https://github.com/     # → 200

# These are blocked despite being in the allowlist:
curl https://google.com/             # → blocked
curl https://www.google.com/         # → blocked
curl https://docs.google.com/        # → blocked

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Claude 1.1.8629 (befdfc) 2026-03-24T22:13:01.000Z

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Other

Additional Information

Claude Cowork