Developer builds AI spreadsheet tool that writes code and verifies its own answers

A developer created Sheet Analysis AI after an AI tool silently skipped rows in a sales spreadsheet and returned a confidently wrong total. Instead of asking a language model to calculate directly, the tool generates JavaScript code from the user's column names and sample data, then executes it locally against the full dataset. A built-in auditor cross-checks every figure multiple ways, including percent math, cross-foot totals, and claim binding, blocking any number that fails verification. The tool supports files up to 100,000 rows and runs entirely in the browser with no backend, using a bring-your-own-key model for advanced AI features. The project is open-source on GitHub, and the developer has framed it as a reusable pattern for making AI reliable with real numerical data.