Frontier model size estimates

The Artificial Analysis Intelligence Index and Epoch Capabilities Index provide audited capability signals, while the No-CoT Time Horizon supplies the primary parameter-scaling branch; API price and compute are lower-weight checks. For Fable and Sol, the public estimate is the geometric mean of parameter-count forecasts from a 20-person poll of researchers and engineers. The goal is to make otherwise opaque frontier-model parameter counts inspectable, adjustable, and reproducible instead of presenting one unexplained guess.