[BUG] Claude freezes on startup attempting connection to github

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 I run claude code the terminal freezes. I can see at the bottom ssh attempt to github:

The authenticity of host 'github.com (20.26.156.215)' can't be established.
ED25519 key fingerprint is SHA256:+DiY3wvvV6TuJJhbpZisF/zLDA0zPMSvHdkr4UvCOqU.
This key is not known by any other names.
Are you sure you want to continue connecting (yes/no/[fingerprint])? 

I made wrapper around a git command and this is what I see:

[Sat Feb 14 10:31:34 UTC 2026] === Container started ===                                                                                                                                                      
  [10:31:34.832810929] git status --short  (caller: claude)                                                                                                                                                         
  [10:31:34.835493429] git log --oneline -n 5  (caller: claude)                                                                                                                                                     
  [10:31:58.238519551] git worktree list --porcelain  (caller: claude)                                                                                                                                              
  [10:31:58.242034342] git -c credential.helper= pull origin HEAD  (caller: claude)                                                                                                                             
  [10:31:58.254391259] ssh -o SendEnv=GIT_PROTOCOL git@github.com git-upload-pack 'anthropics/claude-plugins-official.git'  (caller: git)                                                                       
  [10:31:58.275852634] git worktree list --porcelain  (caller: claude)  

The smoking gun is:

  git -c credential.helper= pull origin HEAD                                                                                                                                                                        
  ssh git@github.com git-upload-pack 'anthropics/claude-plugins-official.git'

This is not my project's remote. Claude Code itself is running git pull on a repo called anthropics/claude-plugins-official.git - an Anthropic-owned plugins repository. It disables credential helpers (-c
credential.helper=) and tries to fetch it over SSH.
Is this documented usage?

What's happening: Claude Code appears to have some kind of plugins/extensions system, and on startup it tries to pull updates from this repo. The SSH connection to github.com for that repo is what blocks my container.

git pull itself just fetches code - it doesn't execute anything by itself. But it's worth noting:

• It's an undocumented network call happening on every startup
• It blocks the entire application when it can't complete (your original problem)
• It uses SSH to a repo I didn't configure
• The -c credential.helper= flag suggests it expects SSH key auth or unauthenticated access

What Should Happen?

claude code should start, claude code should not freeze. claude code should inform something is wrong.

Error Messages/Logs

git -c credential.helper= pull origin HEAD                                                                                                                                                                        
  ssh git@github.com git-upload-pack 'anthropics/claude-plugins-official.git'


The authenticity of host 'github.com (20.26.156.215)' can't be established.
ED25519 key fingerprint is SHA256:+DiY3wvvV6TuJJhbpZisF/zLDA0zPMSvHdkr4UvCOqU.
This key is not known by any other names.
Are you sure you want to continue connecting (yes/no/[fingerprint])?

Steps to Reproduce

start claude code in the container without GitHub's public keys.

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.42

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_