Persimmon
Persimmon is an API-only (closed weights) language model from Humans&, released September 10, 2026. Its makers disclosed about 550B parameters.
The first step in helping someone is understanding them; this is true for both humans & AI. People are unpredictable, behave differently in different social contexts, and change over time. Any model of human behavior needs to represent that variation.
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Lab
Humans&
Released
September 10, 2026
Weights
API-only (closed weights)
Parameters
550B disclosed
Context
–
Price / M tokens
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Epoch ECI
not yet rated
Benchmark results
Epoch AI has not published results for Persimmon yet. New models are usually evaluated within days to weeks.