Where did my agent session go after I closed the window?

It is still on disk. Claude Code writes every session transcript under ~/.claude/projects/, keyed by working directory, so claude --resume in that directory lists your past sessions and reopens the one you pick, with full history. claude --continue skips the picker and resumes the most recent one.

Two things to know: the picker is scoped to the directory you run it from, so resuming from the wrong path shows an empty list, and transcripts are cleaned up after a retention period (30 days by default, cleanupPeriodDays). See I lost my Claude Code session. crystl keeps its own searchable conversation history per shard, and a shard you closed by accident can be brought back whole with undo-close, covered under “I closed a shard by accident” above.