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The wrapper backgrounds claude under `set -m` so the child gets its own process group for the watchdog to reap. But a background process group that calls tcsetattr (the TUI's raw-mode switch) draws SIGTTOU and suspends, so interactive `claude` hung on a blank screen while the wrapper blocked in `wait`, and Ctrl+C then killed the suspended child via the cleanup trap. bash 3.2's non-interactive `fg` cannot transfer tty ownership (no tcsetpgrp), so foregrounding after the fact just re-suspends in a loop; supervision and a foreground TUI are mutually exclusive in pure bash. With a tty, exec the real binary and get out of the way. The watchdog path still covers non-tty runs (scripts, pipes, agent spawns), which is where orphan reaping actually matters. Verified under a pty harness: a stub TUI doing the same tcsetattr now runs to completion with its exit code propagated; the non-tty watchdog path and real-binary passthrough are unchanged. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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Problem
Interactive
claudehung on a blank screen the moment the wrapper went live. The wrapper backgrounds claude underset -mso the child gets its own process group for the watchdog to reap, but a background process group that callstcsetattr(the TUI's raw-mode switch) draws SIGTTOU and suspends unconditionally. The wrapper then blocked inwaitforever, and Ctrl+C killed the suspended child via the cleanup trap.Why not
fgbash 3.2's non-interactive
fgcannot transfer tty ownership (notcsetpgrpaccess), so foregrounding the job after launch just re-suspends it in a SIGTTOU loop. Reproduced under a pty harness. Supervision and a foreground TUI are mutually exclusive in pure bash 3.2.Fix
When stdin is a tty,
execthe resolved binary before any job-control machinery. Interactive runs become byte-identical to bareclaude(signal flow, exit codes). The watchdog path still covers non-tty runs (scripts, pipes, agent spawns), which is where orphan reaping actually pays rent.Verification
tcsetattr: previously suspended forever, now runs to completion with exit code propagated through the wrapper--versionreturns 2.1.220, exit 0🤖 Generated with Claude Code