[BUG] Claude Code silently deletes conversation transcripts after 30 days by default

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?

cleanupPeriodDays defaults to 30, causing Claude Code to silently delete
~/.claude/projects/<project>/<sessionId>.jsonl files older than 30 days on
startup. There is no first-run disclosure, no warning before deletion, and the
setting is not surfaced in /config. I lost months of conversation history
before realizing this was happening.

Repro: Use Claude Code for >30 days without setting cleanupPeriodDays. Old
transcripts disappear.

Evidence on my machine: ~/.claude/history.jsonl shows 14 sessions / 1,315
prompts for one project from March–April. Only the current session's .jsonl
survives in ~/.claude/projects/. The cutoff matches the 30-day default
exactly. My settings.json does not override the default.

Impact: The code and git history remain, but the reasoning trail — design
discussions, debugging context, analysis — is gone. For research work that
context is the artifact.

What Should Happen?

Requested:

1. Change the default to non-destructive (disabled, or very long retention).
2. Disclose at first run; require opt-in for auto-deletion.
3. Soft-delete to a trash folder instead of unlink().
4. Surface the setting in /config.

Workaround for others: add "cleanupPeriodDays": 3650 to
~/.claude/settings.json immediately.

Error Messages/Logs

Steps to Reproduce

Use Claude Code for >30 days without setting cleanupPeriodDays. Old transcripts disappear.

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.150

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Other

Additional Information

_No response_