[BUG] Claude Desktop SSH: Password auth fallback removed in claude-ssh version cee98937, breaking connections that worked in 9e5781db

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?

Claude Desktop's SSH remote connection to a Linux server stopped working after the app auto-updated on April 15, 2026. The claude-ssh binary updated from version 9e5781db to cee98937, and the new version no longer falls back to password authentication when keyboard-interactive auth fails.

Before the update (working, March 31 – April 14):

1. Connects with keyboard: true
2. keyboard-interactive fails: "All configured authentication methods failed"
3. Retries with password auth → succeeds
4. Connected

After the update (broken, April 15):

1. Connects with keyboard: true
2. keyboard-interactive fails: "All configured authentication methods failed"
3. No retry — immediately gives up
4. "Connection failed"

The ssh.log shows this pattern clearly. Every connection from March 31 through April 14 shows the "Retrying with password auth" line followed by success. After April 15 at 07:24 when ClaudeSSHManager initialized with the new version, zero retries occur across 20+ connection attempts.

The server's sshd_config has not changed. The server is reachable (regular SSH from terminal works fine). The other two Claude Code projects (local repos, no SSH) work fine in the same app.

What Should Happen?

Claude Desktop should fall back to password auth when keyboard-interactive fails, as it did in claude-ssh version 9e5781db.

Error Messages/Logs

# Working (April 14, version 9e5781db):
[SSH2Connection] Connection error: All configured authentication methods failed
[SSH2Connection] Retrying with password auth (keyboard-interactive not available)
[SSH2Connection] Connected to tarsadmin@192.168.10.7:22

# Broken (April 15, version cee98937):
[SSH2Connection] Connection error: All configured authentication methods failed
[RemoteServerController] Connection failed (120240ms): All configured authentication methods failed

Steps to Reproduce

1. Have a Linux server where keyboard-interactive auth is unavailable but password auth works
2. Set up SSH remote connection in Claude Desktop (was working before update)
3. App auto-updates, claude-ssh changes from 9e5781db to cee98937
4. All SSH connections fail — "All configured authentication methods failed"
5. No password auth fallback is attempted (previously the app would show "Retrying with password auth")

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

claude-ssh 9e5781db566ba58c6c90b9ea712abbeb62c99eb5

Claude Code Version

2.1.101 (remote CLI), Claude Desktop MSIX latest

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

ssh.log