[BUG] Update notification appears before brew cask is updated, causing "latest version already installed" error

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report
• [x] I am using the latest version of Claude Code

What's Wrong?

Claude Code shows an update notification prompting users to run brew upgrade claude-code, but the Homebrew cask hasn't been updated yet. When users run the suggested command, they get:

Warning: Not upgrading claude-code, the latest version is already installed

This happens because Homebrew casks are automatically updated every 3 hours, but Claude Code's update notification appears immediately when a new version is released on npm. This creates a window (up to ~3 hours or more on weekends) where users are told to upgrade but can't.

Reference: https://github.com/Homebrew/homebrew-cask/pull/243791

What Should Happen?

For Homebrew installations, the update notification should not appear until the new version is actually available in the Homebrew cask.

Error Messages/Logs

$ brew upgrade claude-code && claude --version
Warning: Not upgrading claude-code, the latest version is already installed
2.1.1 (Claude Code)

Steps to Reproduce

1. Install Claude Code via Homebrew (brew install claude-code)
2. Wait for a new Claude Code version to be released
3. Within ~3 hours of release, Claude will show "Update available! Run: brew upgrade claude-code"
4. Run brew upgrade claude-code
5. See the warning that the latest version is already installed

Claude Model

Not applicable (this is about the CLI update notification, not model behavior)

Is this a regression?

No

Claude Code Version

2.1.1 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Other

Additional Information

This issue affects all users who installed via Homebrew. The Homebrew maintainers confirmed they check for updates every 3 hours automatically, so the fix should be on Claude Code's side to account for this delay when detecting the installation method and displaying update notifications.

Possible solutions:

• Detect if Claude was installed via Homebrew and delay the update notification by ~4 hours (I noticed that even though the cask was updated on Brew, there was still at least a 30 minutes delay before I could upgrade).
• Query the Homebrew API to check if the new version is available before showing the notification, cache the result and retry every ~15 minutes to avoid excessive API calls.
• Change the notification text for Homebrew users to mention the potential delay