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William Jeffries

AI engineer and independent AI-safety researcher

Summary

AI engineer with more than twelve years of experience, now conducting independent AI-safety research on agent evaluation, social behavior, and mechanistic interpretability. Built production agentic systems, evals, and monitors.

Independent AI-safety research

Public experiment · 2026

Can agents commit?

Tested Claude Code across 20 Hangman games. The agent kept its secret word in 194 of 194 checks when private working memory carried between turns, compared with 47 of 177 checks when that memory was deleted.

NeurIPS 2026 workshop submission · Under review

Who Verifies the Tools?

Studied how misleading tool-output formatters can cause agents to reach false conclusions and evaluators to accept them. The paper’s audit prompt found an OpenClaw attachment-fetching bug; an OpenClaw maintainer merged the fix before submission.

NeurIPS 2026 workshop submission · Under review

The Case for Kindergarten

Studied how absorbing basins can form in reinforcement-learning environments. Under the tested learning dynamics, models that began with betrayal tendencies reinforced betrayal, while models that began cooperatively reinforced cooperation.

GeBNLP at AACL 2026 submission · Under review

Ablating a Gender Stereotype with Noise

Tested whether concept-ablation fine-tuning could prevent a model from using a gender shortcut without retaining the ablation at inference. Replacing the concept direction with random noise produced higher out-of-distribution accuracy than replacing it with zeroes.

Experience

May 2025–present

Józef Piłsudski Institute of America

AI Engineer · Pro bono

  • Built an 11-tool LangGraph agent for archival research over a six-language archive with 87,218 scans. Tested it with evals designed to limit hallucination.
Sep 2020–Oct 2025

Parachute Health

Senior Software Engineer → Head of DevOps → AI Architect · Contract

  • Architected AI Intake, Parachute’s production agent for checking medical-documentation packets against insurance requirements. Built and maintained its golden dataset and its hallucination and accuracy evaluators using LangGraph and LangSmith.
Apr 2020–Nov 2022

Accent Trainer

Founder · Language-learning startup

  • Prototyped a CNN to detect foreign accent markers in speech, specified the labeling pipeline, and supervised the contractors and labelers who implemented it.
Jul 2014–present

Software consulting: SunGard, Stride, Contino, and independent engagements

Senior Software Engineer and Consultant

Skills

Research and ML
PyTorch, ablation, multi-seed evaluation, distribution-shift evaluation

Evals
Evaluators, eval sets, Promptim, LangSmith, and Langfuse

Education

College of William & Mary