[BUG] Claude CoWork showing Content Security Policy error after Mac OS update

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?

Claude CoWork stopped being able to access the API. This used to work, but seems to have stopped after I updated my macOS to Tahoe 26.3.1

I get ECONNRESET.

Regular Claude chat works fine. This seems related to the VM.

I don't have any firewalls or VPNs.

What Should Happen?

CoWork should be able to connect to the API.

Error Messages/Logs

2026-03-12 16:06:57 [error] Uncaught Error: Minified React error #418; visit https://react.dev/errors/418?args[]=text&args[]= for the full message or use the non-minified dev environment for full errors and additional helpful warnings.
2026-03-12 16:07:29 [error] Connecting to 'https://a-api.anthropic.com/v1/m' violates the following Content Security Policy directive: "connect-src 'self' https://api.segment.io https://*.segment.io https://*.segment.com https://a-cdn.anthropic.com https://*.google.com https://*.facebook.com https://*.facebook.net https://*.doubleclick.net". The action has been blocked.
2026-03-12 16:07:29 [error] Fetch API cannot load https://a-api.anthropic.com/v1/m. Refused to connect because it violates the document's Content Security Policy.
2026-03-12 16:07:29 [error] Error sending segment performance metrics TypeError: Failed to fetch

Steps to Reproduce

Open Claude Code and switch to CoWork tab.

Claude Model

Not sure / Multiple models

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

1.1.6452 5afc23

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

According to @MarshallOfSound is a red herring, per bug https://github.com/anthropics/claude-code/issues/18006