bilig

proompteng/bilig is an open-source project by proompteng: Formula workbooks for Node services: edit inputs, recalculate formulas, read outputs, persist WorkPaper JSON, and expose MCP tools.. Indexed here so it can be found — not resold.

It is free. Get it from the upstream repository: https://github.com/proompteng/bilig

From the project's own README (excerpt, reproduced for discovery under its MIT license):

Bilig

Keep the workbook model. Run the rule in Node.

Bilig is a TypeScript-native, headless WorkPaper runtime for Node.js services, tests, and AI agents. Set inputs, recalculate formulas, read computed outputs, persist WorkPaper JSON, restore it, and verify the result—without driving Excel or a browser grid.

Docs · Quick start · TypeScript API · MCP · Examples · Discussions

> Bilig is a headless workbook runtime, not a visual spreadsheet app or a claim > of full Excel compatibility. If an .xlsx file is your contract, start with > the compatibility report.

Quick Start

Node runtime

Prove the published package before installing it:

The evaluator edits Inputs!B2, recalculates Summary!B2, saves the WorkPaper, restores it, and compares the restored value:

verified: true means the write, formula readback, JSON export, and restored readback all passed. It is stronger evidence than a successful write call.

Use It From TypeScript

For ordinary operations, use set(), setMany(), readMany(), display(), and saveJson(). Use editManyAndReadback() when multiple inputs must be committed and verified as one edit. The complete public API is documented in packages/workpaper/README.md.

The lifecycle is deliberately small:

inputs → formula recalculation → typed readback → JSON persistence → restore verification

Why Bilig

Capability What it gives you ------------------------ ------------------------------------------------------------------------------------------- Workbook-shaped models Sheets, A1 addresses, formulas, ranges, and named expressions without a spreadsheet UI. Verified mutations Before/after computed values plus persistence and restore checks. Service-owned state Portable WorkPaper JSON for routes, queues, tests, tools, and audit…