{"name":"tengu_bg_ptyhost_zombie","slug":"tengu-bg-ptyhost-zombie","family":"flag","title":"Feature flags","noun":"feature flag","description":"Background sessions whose terminal process died are now killed and marked failed instead of hanging.","description_source":"entry","described_by":{"version":"2.1.247","anchor":"dead-background-terminal-hosts-are-cleaned-up-rather-than-hu"},"presence":{"first_seen":null,"removed_in":null,"in_current_build":false,"newest_mined":"2.1.309","builds":0,"mined_builds":150,"first_cited":{"version":"2.1.247","released_at":"2026-08-26 18:02:01","spans":1}},"aliases":[],"entries":[{"version":"2.1.247","anchor":"dead-background-terminal-hosts-are-cleaned-up-rather-than-hu","heading":"Dead background terminal hosts are cleaned up rather than hung on","line":"Background sessions whose terminal process died are now killed and marked failed instead of hanging.","released_at":"2026-08-26 18:02:01","reason":"gate cited by this entry, found in this entry's text"}],"entries_total":1,"docs":[],"docs_total":0,"gates":[],"related":[{"name":"tengu_bg_adopt_upgrade_respawn","slug":"tengu-bg-adopt-upgrade-respawn","description":"Background sessions stop needlessly restarting when your running build is already newer."},{"name":"tengu_bg_agent_action","slug":"tengu-bg-agent-action","description":"Background-agent telemetry no longer records which agent template was used"},{"name":"tengu_bg_attach_outcome","slug":"tengu-bg-attach-outcome","description":"Background attach events now record cold starts, surface and first frame details."},{"name":"tengu_bg_attach_stall_ms","slug":"tengu-bg-attach-stall-ms","description":"Default `5000` (milliseconds). How long attaching to a background session may wait for it to redraw before Claude Code restarts the session with `Session not responding`; after two such restarts it gives up, prints `Session keeps stalling at startup.` and kills the session. `0` turns the restart off; any other value is raised to at least 2000, or 12000 when a background-session launcher is configured."},{"name":"tengu_bg_attach_upgrade","slug":"tengu-bg-attach-upgrade","description":"Default `true`. Gates the background-session supervisor's prewarming: restarting idle background sessions whose recorded Claude Code version is stale onto the running version, in one delayed burst once the supervisor is ready and up to `tengu_bg_prewarm_per_sweep` (default `3`) per periodic sweep while memory is not low. Sessions launched in `exec` mode are skipped and a session on a newer version is not downgraded. Turning it off stops prewarming; the sweep still restarts sessions in its pinned set."},{"name":"tengu_bg_binary_takeover","slug":"tengu-bg-binary-takeover","description":"The background daemon can now retire a same-version instance; build is 2.1.248."},{"name":"tengu_bg_classifier_config","slug":"tengu-bg-classifier-config","description":"Background classifier gets a new, currently inactive setting to control how much recent conversation text it quotes"},{"name":"tengu_bg_classify","slug":"tengu-bg-classify","description":"A new 'Projects' recap mode for the background classifier can summarize thread status, currently unread\/off"},{"name":"tengu_bg_daemon_binary_takeover","slug":"tengu-bg-daemon-binary-takeover","description":"The background daemon can now retire a same-version instance; build is 2.1.248."},{"name":"tengu_bg_daemon_spawn_failed","slug":"tengu-bg-daemon-spawn-failed","description":"An analytics event, not a feature flag. Claude Code logs it when it fails to spawn the background daemon: when spawning a transient daemon with `daemon run --origin transient` errors, when a configured agent launcher's daemon never becomes reachable, and when the daemon's upgrade self-respawn fails to spawn. Fields include `errno_enoent`, `errno_eacces`, `errno`, `launcher_configured`, `failed_stage` or `respawn` depending on the site."}],"url":"https:\/\/changelogs.core-directive.com\/reference\/flag\/tengu-bg-ptyhost-zombie","family_url":"https:\/\/changelogs.core-directive.com\/reference\/flag.json"}