SIGPIPE kills perry programs; node ignores it — claude … | head exits 141 and dies mid-write #9402

claude auto-mode defaults | head -2
  node : rc=0     perry: rc=141

Deterministic, 3/3 each.

Node installs a SIGPIPE handler (or ignores the signal) so a program whose reader closes early finishes normally and sees EPIPE on write. Perry inherits the default disposition, so the process is killed mid-write by any truncating consumer: | head, | grep -q, | less and quitting, a closed socket.

This also caused an unrelated-looking suite failure (hooks case: perry rc=-13 vs node rc=1), so it will keep producing confusing secondary symptoms until fixed.

Fix: ignore SIGPIPE at runtime startup (signal(SIGPIPE, SIG_IGN)) and let writes return EPIPE, which is what every JS runtime does. Worth pairing with a check that write errors surface as JS-visible errors rather than being swallowed.

Found by a differential stress-test of cc 2.1.112 under perry 757beace0.