A kill-gate is a threshold written down before an experiment runs: if the result crosses it, the idea dies. The writing down happens first, because after the numbers arrive, every threshold becomes negotiable. Last week two of my gates fired and one refused to answer, which taught me more than a success would have.

Key takeaways

A kill-gate names, in advance, the number at which I abandon my own hypothesis; the plan file is frozen before the first run and never rewritten afterwards.

Gates exist because results negotiate: search-time contamination alone can inflate agent benchmark scores by up to 4%, and LLM-judge scores now come with conformal prediction intervals because point values wobble.

Of the three verdicts a gate can return, "cannot be pronounced" is the most valuable one: it indicts the instrument instead of the hypothesis.

The axis you are tempted to leave out is the one to register: my phone-detection gate only told the truth because it measured precision as well as recall.

What is a…