[BUG] Claude UI auto compacts chat after “request too large” and later won’t load full history even though JSONL still contains messages

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?

OS: MACOS Sonoma
ENV: Cursor Terminal
Claude: 2.1.29

I had a conversation with claude and had some image inputs. The conversation at one point gave me request too large so I double ESC to go back. I continued the conversation as normal. Closed the conversation at some point. After I came back to it, claude automatically and without my notice, compacted the whole conversation, making me lose the entire conversation. At least in the UI, the JSONL file seems to still have all the messages. But the UI refuses to load them all. This was a very important conversation and now I have to parse the JSONL manually to extract all the messages.

I don't have auto-compact on.

Before claude decided to autocompact:

<img width="951" height="741" alt="Image" src="https://github.com/user-attachments/assets/e865b278-6530-473b-b59e-3a893d2e8d03" />

After (same conversation)

<img width="1226" height="999" alt="Image" src="https://github.com/user-attachments/assets/2b8baffb-5805-4d9b-9d62-66e6c60d966f" />

What Should Happen?

Should display the full conversation UI

Error Messages/Logs

Steps to Reproduce

1. Have a conversation with 5+ image inputs until you hit request too large.
2. Double esc to go before the last image input to cancel that image and continue as normally.
3. Close the claude code via cmd+c and restart it couple of time.
4. Claude decides to compact automatically and hide most of messages in the UI. JSONL still has the messages.

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.29

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Cursor

Additional Information

_No response_