A tool call is one action Claude takes, such as fetching a web page. Claude Code can move a slow tool call to the background (detach it), so the conversation carries on while the call finishes. This feature has changed in several ways:
- Questions after detaching: once a call is in the background, Claude Code records that the session has let go of it. If that call later tries to ask you something, such as the
WebFetchquestion about where content came from, the question is refused instead of shown. - Prompts on screen: a call is not moved to the background while it has a question waiting on your screen.
- Headless sessions: before, detaching was always blocked in non-interactive sessions, meaning runs with no one at the keyboard, such as scripts. It is now allowed there when a further check passes.
- Message to Claude: the note telling Claude that the result "just landed in that call's own row" on your screen is now included only in interactive sessions.
Claude gets wording that matches how the session is actually being run. Background calls no longer stall waiting for an answer that nobody can give. Scripted runs may also be able to send slow tool calls to the background.
tengu_tool_detach Not enough to sayNothing here resolved what this flag was doing on this version, so nothing here should be read as on or off.
This account: no value returned · anonymous baseline: no value returned · compiled default in v2.1.287: on
These values were read against a different version of Claude Code, so treat them as the nearest reading available instead of one taken on this release.
Read once, for one account on one subscription tier, against v2.1.287. It isn't a statement about your account. What a flag value here can and cannot tell you
The extra check that lets non-interactive sessions detach tool calls is not described, so it is unclear whether headless detaching actually…