Under the hoodTier: how much it should matter to you
2Useful: my rating, 1 to 5
2Signal: worth watching, 1 to 5
Background ShellsArea: what it touches
Internal ChangesKind: in v2.1.301,
Internal ChangesSection of the release
What
Claude can run a shell command in the background, meaning the command keeps running while Claude carries on with other work. Its output is saved to a file. When Claude Code reports such a command back to Claude, the report can include three extra details: the task's ID, the path of its output file, and a note about the working folder (the directory the command runs in).
Claude Code now keeps the task ID and output path only when both of these are true:
The ID belongs to a background shell task that Claude Code actually started.
The output path is a plain, complete path of at most 4096 characters, with no . or .. parts, ending in /<taskId>.output.
The working folder note is rewritten into a fixed wording. If it does not match the expected form, a generic message replaces it. That message says, among other things, that folder changes made by the background command do not carry over to later commands.
Why
These details end up in text Claude reads. Checking them stops a forged file path or a misleading folder note from being slipped into Claude's view of a background command.
