Your LLM-as-judge is lying to you

A model grading your agent’s output is the only thing that scales for subjective quality — and it’s a biased instrument you’re reading as a ruler. Here are the biases that actually move scores (position, verbosity, self-preference, leniency), why raw agreement with a human hides them, and how to validate and harden a judge with code — including why you should be reporting Cohen’s kappa, not accuracy.

July 8, 2026 · 10 min · 1958 words · Loop & Retry