Reasoning & knowledge

HELMET

by Princeton NLP

What is HELMET? HELMET is a reasoning & knowledge eval made by Princeton NLP. A long-context benchmark with seven application-style categories, controllable input lengths up to 128K tokens, model-based scoring and few-shot prompts so base models can be tested too. Its study of 59 models found that needle-in-a-haystack scores do not reliably predict real long-context performance.

Page last updated 2026-10-18 · Evals Review

Editor note

A long-context benchmark with seven application-style categories, controllable input lengths up to 128K tokens, model-based scoring and few-shot prompts so base models can be tested too. Its study of 59 models found that needle-in-a-haystack scores do not reliably predict real long-context performance.

What it tests
Long-context models on recall, RAG, re-ranking, citation, long-document QA, summarisation and in-context learning.
Original source
github.com/princeton-nlp/HELMET
Last updated
Repo last commit 2026-09-19
License
MIT

Facts come only from the linked source (checked 15–16 Oct 2026). Credit belongs to the creators. We don't score or rank evals: how we review.

Reviews

No reviews yet.

Reviews are written by people who sign in with GitHub, one per account per eval. We can't confirm that each reviewer used the eval; we remove reviews that break our rules, never just for being negative, and we never add, buy or edit reviews. Averages, when shown, come only from these reviews.

Reviews from practitioners who sign in with GitHub open soon.

Related reasoning & knowledge evals

  • GPQA — Expert-level science reasoning.
  • Humanity's Last Exam — Frontier academic knowledge and reasoning.
  • LiveBench — Hard, contamination-limited tasks with verifiable ground-truth answers (no LLM judge).
  • MMLU — World knowledge and problem solving across many school and professional subjects.

All Reasoning & knowledge evals · Comparison table