Open-Weights AI Capability Frontier (Epoch Capabilities Index)

## What this measures

The best Epoch Capabilities Index score among models whose weights are publicly downloadable, released up to the end of each month.

## Why it matters

Open-weights models are what any company can run on its own hardware at low cost. When they catch up with the frontier, capability stops being scarce and adoption gets cheaper and wider.

## How to read it

Read it against the overall frontier (ai.capability.eci_frontier) and the gap between them (ai.capability.eci_open_gap).

## What it does not say

"Open weights" means the model can be downloaded, not that its training data or code are open. Licences on open-weights models vary. Benchmark scores are not workplace performance.

## Source

Epoch AI, Epoch Capabilities Index (epoch.ai/eci); models in Epoch's "Open weights" accessibility group. Licensed CC BY 4.0. Palanor computes the monthly running maximum.