[BUG] ultraplan 404 preventing the session from starting

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?

ultraplan is giving the following error when using 2.1.96 (Claude Code)

session creation failed — Bundle upload failed: status 404 after 3 attempts. Please setup GitHub on https://claude.ai/code. See --debug for details.

Using --debug did not provide any additional information other than the same error shown above
I asked claude code to help me figure out the issue and it walked me through all of the necessary steps

• web-setup is working and gh is configured properly
• https://claude.ai/code loads as expected in the web-setup and we can see the repo that we are doing work in
• we verified that the Claude is installed in github
• we verified that my claude subscription is Pro which should have access to ultraplan usage
• Claude suggested that I open this bug saying this

File a bug report at github.com/anthropics/claude-code/issues with:

Claude Code version: 2.1.96
Error: Bundle upload failed: status 404 after 3 attempts
Steps: installed GitHub App, ran /web-setup, fresh session, still fails
Repo: private repo under personal account (jdesrochers/web-apps)

After the error happens the claude session goes into regular plan mode which is not what I want. Really want to try out the new ultraplan for my project

IMPORTANT NOTE: the repo that I am trying to use is a personal "private" repo. Claude did not indicate this would be a problem. The fact that I can see the repo when in https://claude.ai/code tells me this should not be related but I wanted to mention this just in case

What Should Happen?

ultraplan should work

Error Messages/Logs

Details in the bug.  Here is the error

session creation failed — Bundle upload failed: status 404 after 3 attempts. Please setup GitHub on https://claude.ai/code. See --debug for details.

Steps to Reproduce

1. Run claude --debug
2. Run /ultraplan <prompt>

NOTE: I am pasting in the contents for the prompt that I wrote out first. However, I also tried just typing a simple prompt and the same thing happens but wanted to provide the additional context

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Claude Code v2.1.96

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_