[BUG]

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?

Title: /ultrareview returns "Could not determine the diff base" twice in a row, both runs counted against free quota

Body:

## What happened

Ran /ultrareview from Claude Code CLI on the main branch of a local
git repo. Both runs returned only an error and produced no review
findings, but both counted against my 3-free-runs quota.

The error returned by the remote agent both times:

{ "error": "Could not determine the diff base in the bundled repo.
This usually means the bundle was incomplete —
try committing locally and rerunning." }

The local stdout reported Scope: 1 file changed, 9 insertions(+), 1 deletion(-)
on both attempts, so the bundler did detect the diff — but the remote
reviewer couldn't anchor it to a base ref.

Between the two attempts I made no local changes, did not branch, and
the relevant commits were already pushed to origin/main. So the second
run failed identically without any user-side variable changing.

## Sessions

• Run 1: https://claude.ai/code/session_01XgfPt2QwYTe5g6kaZxe1wU
• Run 2: https://claude.ai/code/session_01AiDgFiCCypa8ujcHYAyxJg

## What I expected

• Either the run produces findings, or
• The run errors out without consuming a quota credit.

## What I'd like

The two failed runs refunded to my free quota.

## Environment

• Claude Code CLI
• Model: Claude Opus 4.7 (1M context)
• Platform: macOS (Darwin 23.4.0)
• Branch: main, all commits pushed to origin before each run

What Should Happen?

## What I'd like

The two failed runs refunded to my free quota.

## Environment

• Claude Code CLI
• Model: Claude Opus 4.7 (1M context)
• Platform: macOS (Darwin 23.4.0)
• Branch: main, all commits pushed to origin before each run

Error Messages/Logs

Steps to Reproduce

Steps to reproduce

1. From a local git repo with all commits already pushed to origin/main,

on the main branch, run /ultrareview in Claude Code CLI.

1. Wait for the cloud review to complete (~5 min). It returns only:

{ "error": "Could not determine the diff base in the bundled repo.
This usually means the bundle was incomplete —
try committing locally and rerunning." }

1. Quota counter decrements (e.g. "Free ultrareview 1 of 3" → "2 of 3").
2. Rerun /ultrareview without changing any local state. Get the same

error. Quota decrements again.

Both attempts reported Scope: 1 file changed, 9 insertions(+), 1 deletion(-)
in the local launch output, so the diff was detected client-side — the
break happens server-side when the remote agent tries to anchor that diff
to a base ref.

The local repo's origin/main was up-to-date and accessible via HTTPS;
no unusual branching, submodules, or detached HEAD state.

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

claude code

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_