Pick the smallest tool that solves the problem
Three sane options, ordered from heavy to light.
Argilla (recommended for LLM data)
Purpose-built for LLM data. First-class support for preference ranking (DPO/ORPO), text classification, span tagging, and model-suggested labels. Argilla v2 organizes around datasets with configurable fields and questions, hosted as a Hugging Face Space or self-hosted.
Label Studio
General-purpose annotation tool covering text, image, audio, video, time-series. Heavier than Argilla, but the right pick when one team annotates several modalities.
Python script + CLI prompt
For projects under a few hundred examples, a 30-line CLI tool that lets one human approve, reject, or rewrite each example is more practical than a full annotation platform. The right tool is the one your reviewer will actually use.