[BUG] Claude CLI is slow to start

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?

Launching codex is instant whereas there is a lag when I launch claude.

What Should Happen?

For instance it shouldn't take 0.5s to display claude --version, codex --version is 10 times faster

hyperfine "claude --version" "codex --version"
Benchmark 1: claude --version
  Time (mean ± σ):     602.5 ms ±  73.0 ms    [User: 532.4 ms, System: 86.5 ms]
  Range (min … max):   561.9 ms … 801.4 ms    10 runs

Benchmark 2: codex --version
  Time (mean ± σ):      55.3 ms ±  10.9 ms    [User: 44.0 ms, System: 8.1 ms]
  Range (min … max):    47.6 ms …  96.2 ms    57 runs

Summary
  codex --version ran
   10.89 ± 2.51 times faster than claude --version

Error Messages/Logs

Steps to Reproduce

Launch claude, a lag is noticeable

Claude Model

None

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

1.0.123 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Other

Additional Information

_No response_