Follow Discord
Sweep 22 Oct 2026 · 21:04Z Build v2.1.309 528 read Stable v2.1.308 Latest v2.1.308 Next v2.1.309 Feeds RSS JSON llms.txt llms-full.txt Unofficial

Claude Code v2.1.248 ·

Reused session ID exits with an identifiable error code

Reusing a session ID now exits with a machine-readable session_in_use code for SDK callers.

You'll notice No documentation found Bug Fixes
JSON All of v2.1.248
You'll noticeTier: how much it should matter to you
3Useful: my rating, 1 to 5
2Signal: worth watching, 1 to 5
SDKArea: what it touches
Bug FixesKind: in v2.1.248,
Bug FixesSection of the release
What

Starting with a session ID that is already in use now exits with the machine-readable code session_in_use alongside the message, so SDK and wrapper callers can tell this apart from other startup failures. The message you see is unchanged.

Evidence

session_in_use

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Read from
Names in the bundlesession_in_use

See this entry in the whole of v2.1.248 →

Feedback