[BUG] /resume doesn't find recent conversations — sessions-index.json stops being updated

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?

sessions-index.json stopped being updated around Feb 3. It only contains 2 entries, but there are ~25 .jsonl conversation files in the project directory, including sessions from Feb 4–19 that /resume can't find.

Project path: confirmed same directory for all sessions
sessions-index.json: 2 entries, last modified Feb 3
Actual .jsonl files: ~25+, most recent modified Feb 19 (23MB) and Feb 20 (308MB)
/resume returns no results for the unindexed sessions
Running Claude Code in VSCode extension
Possible contributing factor: one session file (b7f728e3.jsonl) grew to 308 MB — unclear if the large file size caused the index to stop updating.

What Should Happen?

/resume should list all prior conversations for the current project directory. Conversation .jsonl files exist on disk but are not indexed in sessions-index.json, so /resume cannot find them.

Error Messages/Logs

No error messages. /resume silently returns no results. Inspecting sessions-index.json shows only 2 entries (last updated Feb 3), while the project directory contains ~25 .jsonl conversation files dated through Feb 19. One session file grew to 308 MB — unclear if related.

Steps to Reproduce

Use Claude Code in VSCode extension on a project over multiple sessions (mine had ~25 sessions over ~4 weeks)
Run /resume
Only 2 old sessions appear — recent sessions are missing
Check ~/.claude/projects/<project-path>/sessions-index.json — only 2 entries
Check ls -lt ~/.claude/projects/<project-path>/*.jsonl — many more .jsonl files exist that aren't indexed

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.49

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

VS Code integrated terminal

Additional Information

Running Claude Code via VSCode extension, not CLI. Sessions started accumulating around Jan 21. The sessions-index.json was last written Feb 3 with 2 entries. After that, new .jsonl files kept being created but the index was never updated. One session file (b7f728e3) grew to 308 MB — possibly related to index writes failing.