What
In headless mode (running Claude Code without its interactive screen, for example from the SDK or another program), Claude Code reads instructions one after another from its input. Some requests can now be answered ahead of earlier input that is still being processed:
- A Stop request is answered straight away while other work is in flight, for example during a file download. Messages you sent before the Stop that are still waiting are cancelled rather than run.
- A turn handoff can be accepted early when no model reply is pending.
- A request to prefetch attachments is answered early.
Before, every request was handled strictly in the order it arrived.
Why
Programs driving Claude Code get a much faster Stop while a turn is still downloading attachments, and messages queued before the Stop no longer run after it.
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubt
Exactly which kinds of earlier input may be overtaken is not fully settled.