Compaction creates new conversation files, causing confusing behavior with --resume

[glazari1]

Description

When conversation compaction occurs, Claude Code creates a new conversation file with a parentUuid field pointing to the original conversation, rather than summarizing in-place within the same file.

This causes confusing behavior when using --resume (-r): users see multiple conversation options even when they have always used -r to continue the same conversation.

Steps to Reproduce

1. Start a conversation in a project with claude -r
2. Work for an extended period until compaction is triggered
3. Exit and run claude -r again
4. Multiple conversation options are shown, even though the user never explicitly started a new conversation

Expected Behavior

One of the following:

• Compaction should summarize in-place within the same conversation file
• OR --resume should only show the most recent conversation in a compaction chain (following parentUuid links)

Actual Behavior

• Each compaction creates a new .jsonl file with a different UUID
• --resume shows all these files as separate conversation options
• Users are confused because they always used -r but see many conversations

Evidence

In a test project with consistent -r usage, 33 conversation files were found. Many shared the same parentUuid, indicating they were created from compaction events, not user-initiated new conversations.

Example files sharing the same parentUuid:

• 15792f2e-...
• 3743cd26-...
• 5631b1e5-...
• 831d2d34-...
• 97867fdc-...
• d6189c54-...

Environment

• Claude Code CLI
• Linux (Debian 12 in LXC container)