Persimmon team reveals internal learning evals were cut from the blog

gharik · x · 2026-10-31

A Persimmon team member revealed in a reply that they had internal evals more directly measuring learning, but couldn't include them in the blog due to limits on what they can publish as a company.

What they do show: Persimmon makes errors at a rate more similar to humans than other models — necessary but not sufficient for matching broader "learning." The most compelling evidence, per the author, is that training against Persimmon's learning signals yields bigger gains on evals built from human-learner data than training against non-Persimmon learners; they hope to validate this in deployment with real learners.

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