[BUG] archive_session MCP tool reports success but doesn't persist

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?

Called archive_session on 26 sessions via the ccd_session_mgmt MCP server. Every call returned a success message (e.g. "Archived session local_<uuid> ("Thread inactivity logger")"). After restarting the app, all 26 sessions still show isArchived: false in list_sessions and remain in the active sidebar.

What Should Happen?

Sessions should actually be archived — removed from the active sidebar and moved to the Archived list, with isArchived: true in list_sessions.

Steps to Reproduce

1. Call list_sessions → note a session with isArchived: false
2. Call archive_session with that session's ID
3. Observe the success message returned
4. Call list_sessions again (or restart the app)
5. Session still shows isArchived: false

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Claude Code Version

2.1.181

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Other (Claude Desktop app)