Robustness & input perturbations

A robust system gives the same answer to the same question asked slightly differently. LLMs often don't: typos, reordered options, added whitespace or an irrelevant sentence can change the output — which means a single passing test proves little. Robustness testing makes the perturbation systematic (metamorphic relations, paraphrase sets, character-level noise) and measures the flip rate. The linked methods and findings show how small the perturbation can be and still matter.