An AI-native terminal spreadsheet. Open a CSV or workbook, navigate and edit like a spreadsheet, write formulas, or just tell Claude what to change. A small, fast, single binary — part of the Fe2O3 Rust terminal suite.

A spreadsheet that stays out of your way and lets the AI do the tedious parts. Type values and formulas directly, or hit I and say "add a Total row that sums each column" — grid hands the sheet to Claude and applies what comes back. No menus, no ribbons: keyboard-driven, instant, scriptable.

• Formats — reads/writes CSV, reads xlsx/ods (via calamine) and writes xlsx (via rust_xlsxwriter), preserving formulas and their computed values.
• Formula engine — hand-rolled, no spreadsheet runtime: arithmetic, ranges (A1:B3), comparisons, & concatenation, and ~25 functions (SUM, AVERAGE, MIN/MAX, COUNT, IF, AND/OR, ROUND, CONCAT, VLOOKUP, …). Whole-sheet recalc with cycle detection (#CYCLE).
• AI editing — I → describe a change in plain English; Claude rewrites the sheet, formulas included.
• Range selection — v starts a rectangular selection; colouring, clearing colour (D) and clearing content all apply to the whole block.
• Cell colours — true-colour (24-bit) foreground/background (C) via the prism picker (or a #rrggbb/name prompt); persists to xlsx natively and to CSV via a .gcolors sidecar.
• Undo — every edit, clear, colour and AI change is undoable (u).
• Multi-sheet — Tab cycles sheets in a workbook.
• Dates — Excel date serials shown as readable YYYY-MM-DD.
• Tiny binary, blocking input — zero idle CPU.

# From a release (Linux/macOS, x86_64/aarch64)
chmod +x grid-* && sudo cp grid-linux-x86_64 /usr/local/bin/grid

# Or build from source (needs the sibling crust crate alongside)
git clone https://github.com/isene/crust
git clone https://github.com/isene/grid
cd grid && cargo build --release

grid budget.csv      # open a file
grid sheet.xlsx      # open a workbook (Tab cycles sheets)
grid new.csv         # start a fresh sheet

=A1+B2*2, ranges =SUM(A1:A10), text =A1&" "&B1, logic =IF(C1>0,"ok","no"), and: SUM AVERAGE MIN MAX COUNT COUNTA PRODUCT IF AND OR NOT ROUND ABS INT SQRT MOD POWER CONCAT LEN LEFT RIGHT MID UPPER LOWER TRIM VLOOKUP.

grid is one tool in the Fe2O3 suite of fast Rust terminal apps. It builds on crust (the TUI foundation) and pairs with viewer, which launches grid for spreadsheet files.

Public domain (Unlicense).