ultraplan: Remote session create failed with 403 on Max subscription

Bug Report

Command: /ultraplan

Error: Remote session create failed: Request failed with status code 403

Environment

• Claude Code version: 2.1.150
• OS: Windows 11
• Auth method: claude.ai
• Subscription: Max (confirmed via claude auth status)
• Repo visibility: Private (GitHub App installed, repo explicitly added)

Steps to reproduce

1. Run /ultraplan <any prompt> from a git repo with GitHub App installed
2. Session creation fails immediately with 403

What was tried

• Re-authenticated CLI (claude auth login)
• Added private repo to GitHub App repository access
• Removed orphaned npm global installation
• Verified Max subscription via claude auth status — returns "subscriptionType": "max"

Expected behavior

Remote session should launch on claude.ai/code

Actual behavior

Remote session create failed: Request failed with status code 403 — every attempt