[BUG] Cowork mode: WebFetch egress proxy blocks most websites (Facebook, Netlify, etc.) AND Chrome extension fails to connect — no fallback path to view any web content

[fassai]

Preflight Checklist

• I have searched existing issues and this hasn't been reported yet
• This is a single bug report (please file separate reports for different bugs)
• I am using the latest version of Claude Code

What's Wrong?

Bug Description

Cowork mode's WebFetch tool is blocked by the egress proxy on most websites — not just niche domains, but major platforms like Facebook, Netlify app deployments, and others. The EGRESS_BLOCKED error fires broadly, making Cowork unable to read web content that both Claude Chat and Claude Code CLI handle without issue.

The natural fallback — Claude in Chrome browser extension — also fails to connect in Cowork. The setup prompt appears but the connection never establishes, returning "Claude in Chrome is not connected".

These two independent failures combine to make Cowork effectively unable to access the web at all.

Tested Examples

URL | WebFetch Result | Chrome Extension -- | -- | -- facebook.com | ❌ EGRESS_BLOCKED | ❌ Not connected *.netlify.app (user-deployed sites) | ❌ EGRESS_BLOCKED | ❌ Not connected (likely many more) | ❌ EGRESS_BLOCKED | ❌ Not connected

Steps to Reproduce

1. Open Cowork mode in Claude Desktop
2. Ask Claude to fetch any commonly used website (Facebook, a Netlify-deployed site, etc.)
3. WebFetch returns EGRESS_BLOCKED error: "Access to [domain] is blocked by the network egress proxy."
4. Ask Claude to try via Chrome extension instead
5. Chrome extension returns "Claude in Chrome is not connected"
6. User is completely stuck — no path to view web content

Expected Behavior

Cowork should be able to access publicly available websites, at minimum matching the capability of Claude Chat (which fetches URLs with no restrictions). The Chrome extension should connect reliably as a fallback, matching Claude Code CLI behavior.

Environment

• Claude Desktop: Latest version (March 2026)
• Plan: Max
• OS: (fill in your OS)
• Chrome: (fill in your version — go to chrome://version)

Impact

This is a fundamental capability gap that makes Cowork the least capable Claude product for any task involving web content, despite being positioned as the most feature-rich.

Suggested Fix

1. Expand the egress proxy allowlist — The current blocklist is too aggressive. Publicly accessible websites (especially major platforms and user-deployed sites) should not be blocked. Match the URL fetching capability of Claude Chat.
2. Fix Chrome extension connection in Cowork — The Claude in Chrome extension connects fine via Claude Code CLI (claude --chrome) but fails in Cowork. These should use the same connection path.
3. At minimum, provide a clear error message — When WebFetch is blocked AND Chrome is unavailable, tell the user explicitly instead of failing silently on Chrome.

---

Reported from Cowork session, March 16, 2026. Tested live with multiple domains.

What Should Happen?

Cowork should be able to access publicly available websites. At minimum it should match Claude Chat's URL fetching capability. The Chrome extension should connect reliably as a fallback, matching Claude Code CLI behavior with claude --chrome.

Error Messages/Logs

WebFetch error:
{"error_type":"EGRESS_BLOCKED","domain":"animated-dusk-d9080a.netlify.app","message":"Access to animated-dusk-d9080a.netlify.app is blocked by the network egress proxy."}

Chrome extension error:
"Claude in Chrome is not connected. The user was prompted to set up the Chrome extension but dismissed the dialog."

Steps to Reproduce

1. Open Cowork mode in Claude Desktop
2. Ask Claude to fetch any website (e.g. https://animated-dusk-d9080a.netlify.app/ or https://facebook.com)
3. WebFetch returns EGRESS_BLOCKED
4. Ask Claude to try via Chrome extension instead
5. Claude in Chrome returns "not connected" — setup prompt appears but connection never establishes
6. No alternative path exists to view any web content

Claude Model

Opus

Is this a regression?

No, this never worked

Last Working Version

No response

Claude Code Version

2.1.45 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

No response

[github-actions]

Found 3 possible duplicate issues:

1. [BUG] Cowork macOS: MITM egress proxy blocks all non-API domains regardless of allowlist settings #30861
2. [BUG]Cowork network egress allowlist not working - custom domains blocked with 403 blocked-by-allowlist #30112
3. [BUG] WebFetch returns 403 on Wikipedia and other sites despite successful preflight check #22846

This issue will be automatically closed as a duplicate in 3 days.

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🤖 Generated with Claude Code

[github-actions]

This issue has been automatically closed as a duplicate of #30861.

If this is incorrect, please re-open this issue or create a new one.

🤖 Generated with Claude Code

[github-actions]

This issue has been automatically locked since it was closed and has not had any activity for 7 days. If you're experiencing a similar issue, please file a new issue and reference this one if it's relevant.