CSV / formula prefix / safe output

Separate CSV formula safety boundaries

Review formula prefixes, quotes, tabs, newlines, neutralization and data preservation with synthetic cells. No real CSV or spreadsheet is handled; only a local review note is produced.

See the decision Save review note

Five output boundaries

CSV quoting and escaping do not remove every condition under which a spreadsheet can interpret a cell as a formula. Keep formula detection and data preservation separate.

formula prefix ≠ quote ≠ neutralize / classify → decide → preserve

Boundary	Review
formula prefix	Review the formula-execution condition for cells beginning with =, +, - or @.
quote	Keep CSV quote boundaries separate from formula detection.
tab / newline	Record row and column boundary changes separately from a formula prefix.
neutralize	State the data-preservation trade-off when changing a leading character.
preserve	Keep original value, changed value and decision distinct.

Safe review order

Classify formula prefixes separately from CSV quotes.
Check whether tabs or newlines change row and column boundaries.
Keep original and changed values before choosing neutralization.
Approve the safe-output note before returning to a real CSV.

This page does not upload, parse or execute a real CSV and accepts no user data. It uses synthetic cells only.

Six synthetic cases

case	result
`formula-prefix`	Formula prefix
`quote-boundary`	Quote boundary
`tab-newline`	Tab and newline
`neutralize-prefix`	Neutralize policy
`preserve-data`	Preserve data
`unsupported-real-csv`	Reject