Nous Research launches Hermes Index to benchmark agentic AI models

Nous Research wants to settle an argument the AI industry keeps having: which model actually gets work done, and what does it cost to find out. The open-source AI lab launched the Hermes Index on October 6, 2026. It ranks frontier models on how well they perform as agents inside the company’s Hermes Agent framework. It also tracks how much each task costs to run. How the Hermes Index works The index measures model performance and cost across four test suites. It averages scores across those benchmarks and calculates a mean cost per task for each model. The centerpiece is a new benchmark called Hermes Bench. It contains 150 tasks spread across 25 categories. The index also folds in other established evaluations, including Terminal-Bench 4.0 and SkillsBench. All of this runs through Hermes Agent, which Nous Research started on February 25, 2026. The lab describes it as an evaluation harness focused on user-aligned model performance. The leaderboard: who won and what it cost Nous Research tested 14 different models in the first edition of the index. Claude Opus 5.5 led the rankings with a score of 63.31. Its average cost came in at $4.99 per task. In second place sat GPT-6 Astra, whic...