Spreadsheets

A grid you edit like a real sheet — arrow keys, Tab, Enter, F2, Escape, Delete, copy and paste, type to edit — with a formula bar. Formulas support cell references and ranges, arithmetic with brackets, percentages and powers, and SUM, AVERAGE, MIN, MAX, COUNT, COUNTA, IF, ROUND, ABS and & to join text. Dependent cells recompute as you type, errors show as #ERR and circular references as #CIRC.

It is seeded with realistic figures, formatted as numbers, currency and percentages, with a live chart.

Built on the Sandbox engine. These are the stages it runs, in order — the same list the builder shows live while it works.

1. 1GenerateAI call

   One forced tool call returns a self-contained HTML document (inline CSS and JS, no external resources).

2. 2Plan checksCode· Spreadsheets only.

   Derives the checks from the same prompt the build was briefed with, so the test exercises the rules that were actually asked for rather than a generic guess.

3. 3Browser testBrowser· Spreadsheets only.

   Opens the document in a headless browser and drives it — types into cells and reads the results back, because a sheet with hardcoded totals is pixel-identical to one that recalculates.

4. 4RepairAI call· Only when the browser test found a failure.

   One more pass, briefed with the exact checks that failed.

5. 5Re-testBrowser· Only after a repair.

   Runs the same checks against the repair, to find out whether it helped.

6. 6Keep or discardCode· Only after a repair.

   Keeps the repair only if it fixed more than it broke. A second opinion that scores worse is a regression, and shipping it would be worse than shipping the original.

7. 7SandboxCode

   Renders into a sandbox="allow-scripts" iframe with an opaque origin — no cookies, no same-origin, no reach into our APIs.

• Download the sheet as CSV.
• Share the link; the sheet works in the browser.

Changes you make in a shared sheet stay in that browser tab — it is a working model, not a shared, saved spreadsheet.