[BUG] Xcode Claude Agent reports "Please authenticate" when ~/Library/Keychains is blocked in Xcode's Agent File & Folder Access settings

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?

When ~/Library/Keychains is set to "No Access" in Xcode's agent file permissions (Settings → Intelligence → Permissions → Control File & Folder Access), Claude Agent can't read its OAuth credential from the login keychain. It then reports this as the user not being signed in, instead of as a Keychain access error, causing confusion that is difficult to troubleshoot even by the AI agent itself.

Symptoms:

• Settings → Intelligence → Claude Agent shows the account as signed in.
• Signing in succeeds and creates the "Claude Code-credentials" Keychain item.
• Claude chat (Claude Sonnet) in Xcode works normally.
• Every Claude Agent prompt immediately returns: "Please authenticate with Claude Agent by going to Settings → Intelligence → Claude Agent → Sign In. After signing in, create a new conversation for the authentication settings to take effect."
• Signing out and back in, deleting the Keychain item, reinstalling the Claude Agent component, and reinstalling Xcode don't help, because the permission rules persist across reinstalls.

This sends users on a long chase through OAuth, browser, and Keychain troubleshooting when the actual cause is a single permission rule.

Expected Behavior

Either:

• the agent reports that it can't read its credential from Keychain because of the file access rules, and says which folder needs access; or
• Xcode warns when a rule blocks a path the agent needs to authenticate.

Actual Behavior

The agent says the user isn't authenticated, even though Settings shows them as signed in.

Workaround

Set ~/Library/Keychains to Read & Write (or click "Reset to Default…"), or turn off Control File & Folder Access. Then sign in again and start a new conversation.

Error Messages/Logs

Error Message: "Please authenticate with Claude Agent by going to Settings → Intelligence → Claude Agent → Sign In. After signing in, create a new conversation for the authentication settings to take effect."

Steps to Reproduce

1. In Xcode → Settings → Intelligence → Permissions, turn on Control File & Folder Access.
2. Set ~/Library/Keychains to No Access.
3. Sign in to Claude Agent under Settings → Intelligence → Claude Agent.
4. Start a new Claude Agent conversation and send any message.

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.220 (bundled by Xcode)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Other

Additional Information

Environment

• Claude Agent (Claude Code) version: 2.1.220 (bundled by Xcode)
• Xcode: 27
• macOS: 27
• Hardware: Apple Silicon (arm64) M1 Pro
• Plan: Claude Max

Also reported to Apple via Feedback Assistant