What probably matters to youSection of the release
What
When the background backend is run as a daemon (CLAUDE_BG_BACKEND=daemon), startup now tries to acquire a controlling terminal for the worker, gated by tengu_bg_worker_ctty which defaults to on. Normal interactive sessions never reach this. If the gate is off it only checks whether a terminal was already acquired.
Details
Outcomes recorded are acquired, already, failed, ffi_unavailable, not_a_tty, unsupported and switched_off.
Failures and the case where the native binding is unavailable are also sent through a separate error-reporting path, not just logged.
Evidence
bg_worker_ctty
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
Read from
Names in the bundleCLAUDE_BG_BACKEND=daemon
Feature flag
tengu_bg_worker_cttyNot enough to say
Nothing 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 v2.1.251: on