[BUG] Startup SSH connectivity check triggers hardware key prompt (YubiKey/GPG agent)

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

On every session start, Claude Code checks GitHub access by running:

ssh -T -o BatchMode=yes -o ConnectTimeout=2 -o StrictHostKeyChecking=yes git@github.com

For users who use gpg-agent as their SSH agent (via enable-ssh-support) with keys stored on a hardware token (e.g. YubiKey), this triggers a GPG pinentry prompt (touch/PIN) on every new conversation — even when the session doesn't involve any remote git operations.

While BatchMode=yes prevents interactive passphrase prompts from OpenSSH directly, it does not suppress prompts originating from the SSH agent. When gpg-agent acts as the SSH agent, it uses its own pinentry program to request user confirmation, which BatchMode cannot control.

Steps to reproduce

1. Use gpg-agent with enable-ssh-support as your SSH agent
2. Have a GPG authentication subkey on a hardware token (e.g. YubiKey) configured for github.com (https://github.com/drduh/YubiKey-Guide)
3. Start a new Claude Code session in any git repo with a GitHub remote

Observed behavior

GPG pinentry prompts the user to authorize the hardware key on every session start, adding friction to the workflow.

Environment

• SSH agent: gpg-agent with enable-ssh-support
• Hardware token: YubiKey
• Confirmed via strace -f -e trace=execve claude 2>&1 | grep -E 'gpg|git|ssh'

Proposed Solution

No user interaction required at startup. The connectivity check should either:

• Be opt-in or deferrable (only run when a remote operation is actually needed)
• Be skippable via a config flag (e.g. "skipGitHubConnectivityCheck": true)

Alternative Solutions

_No response_

Priority

Medium - Would be very helpful

Feature Category

Configuration and settings

Use Case Example

_No response_

Additional Context

_No response_