Typed plan
A plan names the cells to change and what they should contain before the edit.
Early test version / read-only website
Make workbook changes inspectable.
Check what is inside a spreadsheet before changing it. This website can inspect a file and show a summary. It does not change your file or publish an output.
Verified-email sign-in for read-only inspection. No workbook mutation or publication.
What works now and what is still being built · Technical word meanings
example local command
$ invariantbook inspect ./model.xlsx
reading held local bytes …
✓ file size and document checks
✓ values redacted by default
✓ repeatable text summary
! inspection is not recalculation
observable ≠ authorized01 / A narrow path
A safer change has a visible shape.
A tool can suggest an edit. The software must check the request, inspect the result, and get any needed approval before a changed file can be released.
Held snapshot
The software reads one fixed copy of the file. It does not open links found inside it.
Candidate
A candidate is a draft copy with proposed edits. It is not an approved output.
Checks stay visible
The change list shows what happened. Failed checks and unfinished requirements stay visible.
02 / The boundary
Useful now. Honest about next.
This early version can inspect a spreadsheet. The complete edit, check, approve, and publish process is still being built. A passed inspection does not mean an edit is safe.
Available in the reviewed core
Observe, bound, compare.
- Read-only local inspection with fixed diagnostics.
- Typed plans, contracts, policies, and approval checks.
- Finite candidate values and semantic diff observations.
- Receipt observations with canonical references.
Not claimed by this page
Permission is still a separate step.
- Real recalculation through an engine adapter.
- Complete transaction verification and publication.
- Approval authentication or signed authority.
- General workbook fidelity beyond the maintained subset.
Pitch structure follows Guy Kawasaki’s 10/20/30 guidance: ten slides, a short delivery, and readable type. The implementation keeps that spirit without turning hypotheses into traction claims.