[BUG] `Update available` banner suggests brew upgrade when `brew cask` is already at latest

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 CLI persistently shows:

Update available! Run: brew upgrade claude-code

Running brew upgrade claude-code returns:

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

brew info claude-code confirms the installed version matches the latest available cask version. The CLI's internal version check appears to compare against a newer release (presumably npm?) that the brew cask hasn't published yet.

What Should Happen?

The banner should either:

• Not appear when the install method's latest version is already installed
• Suggest the correct upgrade path for the detected install method (e.g., npm install -g @anthropic-ai/claude-code if brew is behind)
• Include the target version number so the user can assess whether it matters

Environment:

• claude-code 2.1.68 (installed via brew cask)
• macOS (Apple Silicon)
• brew cask also reports 2.1.68 as latest

Error Messages/Logs

Steps to Reproduce

Type brew info claude-code into a terminal?

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.68 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

iTerm2

Additional Information

_No response_