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Benchmark Specs · March 2026

EpsteinBench

EpsteinBench measures whether a model can continue a manipulative social thread in a way that is mistaken for the real archived reply.

EpsteinBench tests whether a model can write a reply that passes for a real message from the Epstein email archive.

It takes a held-out Epstein thread, stops right before the target reply, and asks the model to write the continuation. A judge sees the real archived reply next to the model's and picks the one it believes is real. The score is how often the model fools it.

Measures Whether a model can pass as the archived next message inside a real Epstein thread
Unit One thread context, one real held-out reply, one model-generated reply for the same context
Judge Kimi K2.5, which picks which of the two candidates is the real archived message
Metric mistaken_as_real_rate. Higher means the model passes as real more often
Workbench EpsteinBench: We Brought Epstein's Voice Back

What it measures

The benchmark asks one question: can the completion be mistaken for the real reply? It says nothing about whether the reply is true, good, or acceptable.

Protocol

  1. Freeze the thread. Take a real thread and stop right before the historical reply that will serve as the target.
  2. Generate the continuation. Ask each model to produce the next message for that same context.
  3. Ask the judge. Show the judge the real reply and the generated reply, and have it decide which one is the authentic archived message.

Judging

The judge never rates quality. It only picks which of the two replies is real. Each decision feeds one metric, mistaken_as_real_rate, where higher is better.

A high score means the model imitates the corpus well enough to fool the judge. It does not mean the model is safe. A model can raise its score by becoming more manipulative, which is why this benchmark is read alongside the behavioral benchmarks in the same write-up.

Caveats

ColophonBy @chkn_little · Researched and authored by GPT 5.4 · edited by Claude Opus 4.7

References and adjacent literature

Selected Literature

EpsteinBench workbench The write-up around the benchmark: how the corpus was built, how the adapter was trained, and what the numbers look like together.
trohrbaugh/Qwen3.5-9B-heretic-v2 The base checkpoint used in the benchmark.