[BUG] Diff widget only shows first file change, misses subsequent commits

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?

Description
When multiple commits are made in a single Claude Code session, the diff widget in the chat UI only shows the diff from the first file-writing operation. Subsequent commits that create or modify other files are not reflected in the diff view.

Steps to Reproduce
Start a Claude Code session
Edit an existing file and commit it (e.g., tool-instructions.md — shows +133 -25)
Create a new file in a second commit (e.g., .claude/skills/debug-deploy/SKILL.md)
Create another new file in a third commit (e.g., .claude/skills/devops-railway/SKILL.md)
All three commits are pushed to the branch successfully
Expected Behavior
The diff widget should show the aggregate diff across all commits in the session, or show multiple diff entries — including the newly created files.

Actual Behavior
The diff widget only shows +133 -25 from the first commit (tool-instructions.md). The two new skill files (74 lines and 258 lines respectively) added in commits 2 and 3 are completely missing from the diff view.

Evidence
git log confirms all 4 commits are on the branch and pushed:

26a44f9 Add devops-railway skill for Railway platform management
e87f980 Add debug-deploy skill for Railway deployment failures
e686d37 Update JIRA instructions: email now available, all ops verified
480736e Update tool-instructions.md with verified API instructions

The diff widget only shows the changes from commit 480736e.

Environment
Claude Code on the web (Claude Desktop cloud session)
Model: Claude Opus 4.6

What Should Happen?

diff should show all changes in my feature branch. this was working before I guess regression.

Error Messages/Logs

Steps to Reproduce

Steps to Reproduce
Start a Claude Code session
Edit an existing file and commit it (e.g., tool-instructions.md — shows +133 -25)
Create a new file in a second commit (e.g., .claude/skills/debug-deploy/SKILL.md)
Create another new file in a third commit (e.g., .claude/skills/devops-railway/SKILL.md)
All three commits are pushed to the branch successfully
Expected Behavior
The diff widget should show the aggregate diff across all commits in the session, or show multiple diff entries — including the newly created files.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

I am using claude desktop and don't know how to extract the version from the desktop tool

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_