create-sheet

Create a workbook in open-sheet

This skill owns the workflow. The technical reference — file contract, components, references, formats — lives in the sheet-authoring skill. Read it before writing code; do not duplicate its rules here.

You only write files under sheets/<id>/. Never modify package.json, open-sheet.config.ts, or an existing workbook unless asked.

Step 0 — Pick a theme

List themes/. If any theme markdown exists, offer each theme id via AskUserQuestion plus a final "no theme — design from scratch" option. If the user picks one, read themes/<id>.md end to end, copy its palette and components, and set meta.theme.

Step 1 — Get the numbers before anything else

A spreadsheet is judged entirely on whether its numbers are right. Before structure, before layout, establish:

• Purpose — what decision does this workbook support? A budget to approve, a forecast to argue with, a register to maintain?
• Audience — a CFO wants assumptions they can change; an analyst wants the working; an ops team wants a list they can filter.
• The data — where does it come from? Ask for the file, the query, the figures. If the user has none yet, build the structure and leave explicit TODO: markers.

Never invent a figure. Not a revenue number, not a growth rate, not a headcount, not a "typical industry" benchmark. A fabricated number in a spreadsheet is indistinguishable from a real one — it will be formatted, totalled, and charted exactly like the truth, and someone will make a decision on it. This matters more here than in a slide deck or a report.

If you need a placeholder to demonstrate structure, make it obviously fake (0, or 1 with a <Note> saying so) and tell the user.

Step 2 — Clarify the shape (ask before writing code)

One AskUserQuestion call, skipping anything the user has already settled:

1. Workbook type — propose three that fit this request, with what each implies structurally:
   • "our FY26 numbers" → driver model (assumptions sheet drives a P&L) · budget vs actual (variance columns and a data bar) · exec summary (one sheet, KPI band, no working shown)
   • "track our vendors" → register (one row per vendor, filterable) · spend analysis (grouped totals, top-N) · scorecard (weighted criteria)
2. Assumptions — which numbers should the reader be able to change? This is the question that decides whether the export is a model or a picture.
3. Sheets — one sheet or several? Assumptions separate from calculations is the default and should only be collapsed for a genuinely trivial workbook.
4. Output — is this opened in Excel (the usual case), printed as a report, or read as a dashboard? It changes formats, widths, and whether to add a --html pass.