Under the hood
Forked slash-command subagents now register in a task registry and share an abort controller with their caller
What
When a slash command runs as a forked subagent (a separate agent process spun off to handle it), it now registers itself into a taskRegistry with an abort controller linked to the caller, and marks its status as 'failed' or 'completed' when it finishes. This replaces the previous, simpler cleanup call.
Why
This gives Claude Code a more structured way to track and cancel forked subagent tasks tied to slash commands, including propagating cancellation from the caller.