open-sheet
A spreadsheet framework built for coding agents: a model is written as React components, and open-sheet resolves cell addressing, formula references and recalculation and exports a live, working .xlsx file that recalculates when a value changes.
open-sheet lets a coding agent describe a financial or data model in React rather than by writing spreadsheet formulas directly, then handles cell addressing, formula references, recalculation and export to a live .xlsx workbook. Rather than writing a cell address such as SUM(B2:B13) by hand, a reference is expressed through a typed API, such as picking a column from a named table, and resolved to an address at compile time, so inserting a row does not silently break a formula the way a hand-written address can.
When a value cannot be computed it is marked with an explicit not-evaluated placeholder rather than a plausible-looking number. Because it still writes live Excel formulas, the resulting workbook recalculates in Excel's own engine using Excel's own numbers, and a reviewer looking at a change reviews the source as a normal code diff rather than a binary spreadsheet diff.
It is described as the third medium in a series alongside an open-slide and an open-doc project, and installs with a single command that scaffolds a new project through its command-line interface.