Worktree/branch auto-naming gets stuck on one name ("spreadsheet-sync") across unrelated sessions in the same repo

Summary

The auto-generated git worktree/branch name (and the session title that inherits it) gets stuck
on a single stale slug for a given repo, regardless of what the session actually does.

Evidence

In one local repo, 10 of ~18 recorded worktree sessions since 2026-08-30 all carry the name
spreadsheet-sync-<hash>, while every other repo/session gets a distinct, content-appropriate
name (e.g. karpathy-second-brain, tailscale-device-m1pro, nuc-temperature-warning).

Checking what those 10 "spreadsheet-sync" sessions actually did shows the name is completely
decoupled from content — none of them involved a spreadsheet:

• job-scraper Playwright fix
• iCloud backup false-backlog nag
• Patroni docs page-break formatting
• storage/census work reconciling data to .tsv (the only even-adjacent one)

Suspected trigger

Sessions that open with a slash command (e.g. /ss, a session-start checklist) rather than an
immediately distinctive task prompt seem to correlate with hitting the stale name — one of the
affected sessions' first logged action was literally /ss health check, same as a fresh session
that also landed on spreadsheet-sync. Guess: when the namer has no distinctive task content yet,
it falls back to a cached/previous name for that repo instead of generating fresh, and that stale
value never gets invalidated.

Expected behavior

Each new worktree/session should get a name generated fresh from its own task content (or a
random codename), not a name recycled from an unrelated earlier session in the same repo.

Environment

• Claude Code desktop app
• macOS