[BUG] Cowork Windows: WebFetch egress proxy blocks all domains regardless of "All domains" allowlist setting

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?

The WebFetch tool in Cowork returns EGRESS_BLOCKED for all domains, even when the Domain allowlist is set to "All domains" and the network egress toggle is enabled. The allowlist setting has no effect — every domain is blocked regardless.

Related macOS issue: #30861 — this appears to be the same underlying bug on Windows.

What Should Happen?

WebFetch should successfully retrieve content from any domain when the allowlist is set to "All domains." The egress proxy should respect the user's configured allowlist setting.

Error Messages/Logs

{"error_type":"EGRESS_BLOCKED","domain":"en.wikipedia.org","message":"Access to en.wikipedia.org is blocked by the network egress proxy."}

Same error returned for every domain attempted, including vengapaging.com, fusioninvoice.com, xagle.com, torqueforks.com, and others.

Steps to Reproduce

1. Open Claude Cowork desktop app on Windows
2. Go to Settings → Capabilities → Code execution and file creation
3. Enable "Allow network egress" toggle
4. Set Domain allowlist to "All domains" (UI confirms: "Claude can access all domains on the internet.")
5. Start a Cowork session
6. Ask Claude to use WebFetch on any URL (e.g. https://en.wikipedia.org/wiki/Wikipedia:Signs_of_AI_writing)
7. Observe EGRESS_BLOCKED error regardless of allowlist setting

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Latest (Cowork desktop app, updated 2026-04-14 — exact version unknown, claude --version N/A in Cowork)

Platform

Other

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

This bug is in the Claude Cowork desktop app (Windows), not the Claude Code CLI. The "Terminal/Shell" and "Platform" fields above don't map cleanly to Cowork — Platform is "Other" and the terminal field is N/A.

Steps to reproduce:

1. Open Cowork on Windows
2. Settings → Capabilities → Code execution and file creation
3. Enable "Allow network egress," set Domain allowlist to "All domains"
4. In a Cowork session, use the WebFetch tool on any domain

The setting is confirmed correctly configured (screenshot attached in mind — "Claude can access all domains on the internet." shown in the UI). Despite this, every WebFetch call returns EGRESS_BLOCKED.

The macOS version of this bug is tracked in #30861. This confirms the issue is cross-platform.