You'll notice
Useful3 Signal2
If your session id is taken, Claude Code starts under a fresh one instead of colliding.
What's wrong with this entry?
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What
When Claude Code restarts a session and finds its session id already in use by another conversation, it now generates a fresh id and continues instead of colliding. It warns "session id was taken by another conversation; starting under a fresh id".
Details
- Triggered when the stored session row is marked as taken, has no recorded CLI version, and is not a resume fork.
- Both the session id and the resume session id are rewritten to the new id, and the taken marker is cleared.
Evidence
session id was taken by another conversation; starting under a fresh id
Strings lifted out of the shipped bundle, so the claim above can be checked against them.