Sphere
Lead AI Engineer
$250K–$280K
San Francisco HQ · On-site · Full-time · Posted Oct 7, 2025
About the job
Lead development of TRAM, Sphere’s AI reasoning model for interpreting global trade law and producing accurate compliance determinations.
What you'll do
- Develop features and data/retrieval pipelines to improve TRAM’s test-time accuracy; work with tax experts to guide its reasoning.
- Own TRAM’s evaluation framework and workflows.
- Work with frontier labs on fine-tuning models using proprietary data.
What they ask for
- Prior experience building AI-enabled products, particularly RAG systems.
- Experience fine-tuning base models, ideally via RFT.
- Willingness to study tax technical problems and tax research reasoning.
- Strong understanding of LLMs and reasoning models.
Nice to have
- Experience applying LLMs to legal applications.
- Experience with RAG data pipelines and collecting or curating pipeline data.
Pay
$250K – $280K (base salary)
Tools
TRAM, RAG, LLMs, RFT
AI focus
Build and improve an AI reasoning model for interpreting trade law, including data and retrieval pipelines, accuracy evaluation, and fine-tuning.
Model-written summary · the original posting is authoritative