Here are three runs of the same command against the same missing file, measured on 2026-09-04 in bash on Windows. $ node tools/antiai_gate.mjs --file /nonexistent-xyz.md > /dev/null 2>&1 ; echo $? 1 $ node tools/antiai_gate.mjs --file /nonexistent-xyz.md 2>&1 | tail -1 > /dev/null ; echo $? 0 $ node tools/antiai_gate.mjs --file /nonexistent-xyz.md 2>&1 | tail -1 > /dev/null ; echo ${ PIPESTATUS [0] } 1 ...