Product UpdatesBuilding Sheldon's State Tax Engine: 98% on TaxCalcBench
Deterministic rule engines for California, Illinois, New York, and Virginia - 620 of 630 scored lines on TaxCalcBench, every gap a documented benchmark defect.

This week we added temporal awareness to RAG and launched the AI tax tool comparison page..
Welcome to our weekly update. This week we added Temporal Awareness so that answers match the right tax year. We also launched the AI Tax Assistants comparison page.
Temporal Awareness for RAG: We upgraded our Retrieval Augmented Generation (RAG) system with temporal awareness. Feather now analyzes the timing of laws, cases, and regulations, and considers the specific dates of your questions. When you ask about a rule, Feather can distinguish between current guidance and prior-year details, so answers reflect the correct time frame. Whether you need the most recent update or precedent from previous years, the system surfaces the most timely information for your research. The feature is currently in Alpha and will be released globally by the end of this week.
Tax AI Tool Comparison Page and Evaluation Framework: We launched a comparison page for AI Tax Assistants so you can explore options side by side, plus a transparent "How we evaluate" framework that shows how each tool performs on accuracy, citations, legal reasoning, and practical guidance. You can assess every solution using clear, consistent criteria.
That's all for this week's changelog.
Take care!
Product UpdatesDeterministic rule engines for California, Illinois, New York, and Virginia - 620 of 630 scored lines on TaxCalcBench, every gap a documented benchmark defect.
Product UpdatesA deterministic tax calculator built on a dedicated knowledge base and AI-generated rules - and how it went from 50% to 190/190 on TaxCalcBench.
Product Updates

Written by Sokratis Vidros
Published on February 23, 2026