visi

[!NOTE] While use of LLMs for generating code is encouraged, LLM-generated prose is severely restricted. See the LLM policy for more details.

Overview

visi is a CLI application for editing and evaluating Excel spreadsheets.

Goals

• Match Excel's execution behavior 100%, including pivot tables and macros (VBA).
  • In some cases, visi even produces more numerically accurate results
  • Excludes some functionality that require Microsoft web services
  • visi aims to match the classes of errors that Excel produces, but not the error message itself (visi may be able to improve upon Excel here)
  • Documented discrepancies
• Prioritize performance
  • Written in Rust to maximize potential performance capacity
  • Fast startup time
  • Handle large workflows

Why visi

LLMs are good at authoring spreadsheets with existing tools (such as openpyxl for Python), but in order to evaluate the formula results, you need a real spreadsheet application. Excel is unsuitable for headless evaluation of spreadsheet files, especially on non-Windows platforms (e.g. no COM automation).

visi aims to bridge this gap by providing an execution/verification layer for spreadsheets.

Installation

Homebrew (macOS/Linux)

brew install albert-yu/tap/visi

Examples

Inspect Workbook Structure

# Display summary of sheets, dimensions, and formula counts
visi info data.xlsx

# Output summary as JSON
visi info data.xlsx --json

Read Sheet Contents, Ranges, or Cells

# View first sheet as a formatted ASCII table in the terminal
visi read data.xlsx

# View specific sheet and range
visi read data.xlsx --sheet Sheet1 --range A1:C10

# Read a single cell result or raw formula
visi read data.xlsx --cell A1
visi read data.xlsx --cell A3 --raw

visi read data.xlsx --format csv
visi read data.xlsx --format json

Recalculate Formulas

You can take a spreadsheet authored with openpyxl and perform the computation with eval.

# --in-place or -i will write back to the input file
visi eval data.xlsx --in-place

# Recalculate and print to stdout,
# leaving the original workbook unmodified
visi eval data.xlsx --print --format table

Update Cells & Set Formulas

visi set data.xlsx --sheet Sheet1 --cell A1 --value 100 --output updated.xlsx

# Set multiple cell values and formulas at once
visi set data.xlsx -s Sheet1 -S A1=100 -S A2=200 -S A3="=A1+A2" -S A4="=AVERAGE(A1:A2)" -i

# Cross-sheet reference
visi set data.xlsx -s Sheet2 -S B1="=Sheet1!A3 + 50" -i

Manage Worksheets

visi sheet list data.xlsx
visi sheet add data.xlsx --name "Summary" -i
visi sheet rename data.xlsx --old "Sheet1" --new "Data" -i
visi sheet delete data.xlsx --name "OldSheet" -i

Manipulate Rows and Columns

Use --index for a 0-based offset or --label if you want to follow the UI labels.

# Insert a new row at start
visi row delete data.xlsx --sheet Sheet1 --label 1 -i
visi row insert data.xlsx --sheet Sheet1 --index 0 -i

# Delete column label 'C'
visi col delete data.xlsx --sheet Sheet1 --label C -i
visi col delete data.xlsx --sheet Sheet1 --index 2 -i

Export Sheet Data

visi export data.xlsx --sheet Sheet1 --format csv --output sheet1.csv
visi export data.xlsx --sheet Sheet1 --format json --output sheet1.json

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Development

This monorepo is structured follows:

• visi-core: embeddable spreadsheet engine that parses and executes the formulas in the workbook
• visi: Command-line application using visi-core which can edit and execute Excel files headlessly

visi aims for feature parity with Excel by using a harness that drives a real copy of Excel via AppleScript or COM automation, runs computations, and compares the results. Both the cell values and types should match exactly. See fuzz for more details.

LLM Policy

• LLMs may be used for source code generation
• No LLM-generated comments in source code
• No LLM use for writing prose, unless clearly attributed at the beginning of the content
• EXCEPTION: commit messages may be 100% LLM-authored
• AGENTS.md should automatically enforce this

License

Dual-licensed:

• Apache License, Version 2.0
• MIT License