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.

Sheldon prepares Forms 8283, 8949. On-demand tax watches, diagrams in chat, nested folders.
Sheldon expands support for Forms 8283 and 8949, tax watches are now on-demand, and Feather introduces diagrams in chat, nested folders, and PDF exports with QR codes. Plus, all users benefit from the latest Gemini model. Here’s everything released between September 13 and 23.
Sheldon can now prepare Form 8283 (Noncash Charitable Contributions) and Form 8949 (Sales and Other Dispositions of Capital Assets). Both forms are generated from the return data Sheldon already processes, so they appear in the output without a separate step.
A related fix ensures each form is filed once per person on a joint return. If two filers have separate K-1 income or noncash contributions, the forms come out correctly attributed rather than duplicated.
K-1 ingestion also improved. More Schedule K-1 phrasings and source-box variations are now recognized, reducing the chance a K-1 line goes unread. California Form 540 got expanded calculation coverage as well.
Sheldon, our tax prep agent, is still in private beta. Interested in early access? Get in touch.

Tax watches check a client situation for changes that affect their return. Until now, checks ran once a day. You can now trigger a check from the Workflows page whenever you want - useful when a client sends new documents and you need an immediate answer on whether anything changed.
A related fix scopes each watch to files ingested after it was set up, so earlier uploads no longer produce alerts on a watch that didn't exist when they were added.
Following last week's improvements, Tax Reviews continues to get more accurate:
When Feather's answer includes a diagram written in Mermaid syntax, it now renders as a visual diagram.
Project sources now support nested folders. You can browse into subfolders and create new ones from inside a project, which helps with larger document sets that need more than a flat list.
When you export a chat as a PDF and the chat has a public share link, the exported PDF now includes a QR code pointing to the shared version. Recipients can scan it to open the interactive version directly.
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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, Shashi Mittal, Danko Komlen, George Desipris
Published on September 23, 2026