debugging
5 min read
A failure with no witnesses: one query pipeline that silenced all three channels
A jq command over a saved MCP result printed nothing and exited 0 — no data, no error, no failure. Every one of those was manufactured by the caller: a wrong schema emptied stdout, a defensive 2>/dev/null ate the one diagnostic line, and | head laundered jq exit code 5 into 0. A Unix pipeline has three signal channels; habits acquired as defenses can close all three at once.