Dexterity Sheets

Start in three steps

1. Install. Download DexteritySheets-Setup.exe and double-click it. No administrator rights, nothing else to install. If Windows says "Windows protected your PC", click More info → Run anyway (the installer isn't code-signed yet).
2. Sign in. Open Dexterity Sheets and go to File › Shared. The office server is found on its own; enter the user name and password IT gave you.
3. Share and edit together. Open any workbook from wherever you keep it (your D: drive, a project folder, the network drive) and click Share › Share…. The file stays where it is and keeps everyone's edits; your team sees each other's changes almost instantly.

What it does for you

A look around

What's new

Everything in 1.4.1

Dexterity Sheets is built on the open-source GridCraft spreadsheet. Every improvement made there is merged in automatically, tested, and delivered to every desk by the built-in updater, usually within hours.

Questions

It looks and works the way you expect: the same ribbon tabs, the same shortcuts, 500+ functions (VLOOKUP, XLOOKUP, SUMIFS, IFS, dynamic arrays…), tables, conditional formatting, charts, filters and printing. It reads and writes real .xlsx files that Excel opens without complaint. Dates and numbers follow your Windows settings (dd-mm-yyyy, 12,34,567) like Excel does.

No. Everything runs on the office network: your files stay in your folders, and the office server passes edits between PCs and keeps the history. Nothing goes to anyone's cloud. The office server goes online to fetch new versions; a PC that has no office server reads this repository's releases page itself (only that, checksummed; switch it off in the updates dialog if you prefer).

Both changes are kept in Edit History. The one the server received last is the value everyone sees, and everyone ends up with exactly the same workbook. People editing different cells never get in each other's way, and Undo only takes back your changes.

Keep working. Your edits are kept on your PC and go through as soon as the office server can be reached again; the status bar shows how many are waiting. Nothing the server has confirmed can be lost: it writes every change to disk before anyone else sees it.

Yes, and that's the normal way to work. Open the file from wherever it is saved (D:\Projects\…, your Desktop, the network drive), then click Share › Share…. Nothing is moved or copied anywhere for you to look after:

• Your teammates find it in File › Shared, listed as your file, and edit it with you live.
• Your file is saved with everyone's edits as they happen, so it is always the team's latest. Ctrl+S saves it at once and also keeps a version.
• When the work is done, Share › Stop sharing hands the file back to you with every edit in it. Everyone else is told, and keeps a copy in their window.

A file that isn't shared is just a file: open and save .xlsx and .csv anywhere, like any spreadsheet.

They join the live workbook instead of editing a copy of their own, so a file on the network drive never splits into two versions. If you close a shared file and open it again later, it rejoins and catches up with what the team did meanwhile.

It is never overwritten. If another program (Excel, a copy from email) saves over a shared file, Dexterity Sheets stops writing to it and says so. Everyone's edits are still in the shared workbook: use Save As to keep them as a file.

Only people with an account on the office server. IT gives each person a role: viewer (read only), editor (edit, create, share) or admin. Every change is recorded with the name of the person who made it.

You don't have to do anything. When a new version is out, the status bar shows Update to X.Y.Z: click it and Dexterity Sheets installs the update and reopens (unsaved workbooks are asked about first). You can also use Automate › Check for Updates…, which asks the office server and this repository's releases page and tells you what each answered. A PC with no office server still gets updates this way, a few seconds after it starts and once a day.

That message appears for any program that isn't code-signed yet. Click More info → Run anyway. Every release lists SHA-256 checksums and is built and tested automatically from the code in this repository.

For IT

From the latest release:

File	What it is
DexteritySheets-Setup.exe	The installer for everyone: double-click. Per-user, no administrator rights, no extra runtimes. /quiet or /passive for silent installs, /log <file> for a log.
dexterity-sheets-<version>-windows-x64.msi	The same installer as an MSI, for deployment tools: msiexec /i … /qn
dexterity-sheets-<version>-windows-x64-portable.zip	Runs without installing
DexSheetsServer-Setup.exe	The office server, for the one always-on PC: double-click. Installs the server as a Windows service and the Server Manager. /quiet for silent installs.
DexSheetsServer-<version>-x64.msi	The same server installer as an MSI, for deployment tools
SHA256SUMS	Checksums of all of the above

Before any release is published it has passed the full test suite, a live three-window co-editing test, and installer tests: the app's two installers are installed, started, asked to calculate and uninstalled; the server's two are installed, checked for a running service, the firewall rules and a locked data folder, opened in the Server Manager, and uninstalled.

1. On the office PC that stays on, run DexSheetsServer-Setup.exe from the latest release and click Install (Windows asks for administrator rights once). It installs the server as a Windows service that starts with Windows and restarts itself if it ever stops, and opens the firewall for the office network only.
2. The Dexterity Sheets Server Manager opens. Create the first administrator account.
3. Add your team on the People page, one by one, or many at once on Add many people: type them into the list, paste rows copied from Excel, or click Download template, fill it in, and Import from file. Every row is checked before anything is created; passwords left empty are made for you. Then Save the sign-in sheet to hand the passwords out.

Everything else is in the Server Manager too, so the job can be handed to anyone:

Page	What it does
Server	Running or stopped, with Start / Stop / Restart; the name, computer name and addresses teammates use; whether the firewall is open (and a button to open it); the data folder and its size; the server log
People	Everyone who can sign in: change a role, reset a password (a readable one is made and shown once), disable or remove. The last administrator can't be locked out.
Add many people	The bulk list described above
App updates	Fetch new versions of Dexterity Sheets from this GitHub repository automatically, or add an .msi by hand; every PC on the network is offered it
Backup and restore	One .zip with every account, shared workbook, edit history and version; restoring keeps the data it replaces
Installed versions	Which Dexterity Sheets version each PC runs, its channel and when it was last seen, with a count per version
Releases	Each installer's channel (stable or testing), status (OK, known issue, deprecated, blocked) and the note people running it see; which version stable and testing PCs are offered and where a blocked version rolls back to; whether updates are offered, installed on their own or never offered
Feedback	Problem reports sent with Help › Report a Problem, grouped by version and feature, each readable in full (with its logs when included); Open GitHub issue fills in a new issue without names of people or PCs
System health	Failed updates, starts after a crash or forced shutdown, and errors, per version over 7 and 30 days, and the latest 50
Feature adoption	The 30 most used commands and the rarely used ones over 7, 30 or 90 days, for all versions or one (command names only)

Roles: Editor (edit, create and share), Viewer (read only), Administrator (also manages shared workbooks). The data lives in C:\ProgramData\Dexterity Sheets\Server, readable only by administrators; uninstalling never deletes it. Full guide: docs/collaboration.md.

Share	Open the file from wherever it is saved and click Share › Share… (or File › Shared › Share the current workbook). The file stays where it is: the app of the person who shared it saves everyone's edits into it a second after each change, and on Ctrl+S. File › Shared › New shared workbook starts an empty one.
Who can open it	Everyone at the office, or named people, each as an Editor or a Viewer, optionally until an end date; choose whether viewers may save a copy. Copy link gives a link for a chat or e-mail that opens the spreadsheet in the app after checking the reader's access.
Where your edits are	The status bar says saved on the server, saving N edit(s), offline or out of step, reloading; a workbook being shared shows Sharing · uploading until the server has it.
Opening a shared file	Opening a file that is being shared joins the live workbook, so a file on the network drive never splits into two versions. Reopening your own shared file rejoins it and brings the file up to date.
Stop sharing	Share › Stop sharing (keep my file): the file gets every edit and is just a file again; everyone else is told and keeps a copy in their window. If another program changed the file while it was shared, it is never overwritten: the app says so and the edits stay in the shared workbook (Save As keeps them).
See each other	Other people's selections are outlined in their colour with their name; "(typing)" while they edit a cell. Click a name in the status bar to jump to them.
Who changed it	The status bar shows who last changed the active cell. Click it, or Review › Edit History (Excel's Show Changes), for that cell's history or the whole workbook's, filterable by person.
Versions	Review › Versions: keep a labelled version ("Issued for review Rev B"), open any version as a separate copy, or restore one for everyone (the current state is kept first). Ctrl+S keeps a version too.
Offline	Edits made while the server can't be reached are kept and sent on reconnect; the status bar shows how many are waiting.

What the server keeps on disk, and why nothing acknowledged can be lost, is in docs/collaboration.md.

For developers

A test harness drives Microsoft Excel itself (through COM, as a black box) and compares: formula results, number-format display, typed entry, CSV import/export, and files written by each application opened in the other.

Check	Result
Files written by Dexterity Sheets opened in Excel	15/15 open, 0 repair prompts
Excel recalculating our files	0 differences
Function results vs Excel (295 formulas + dynamic arrays)	343/344
Number-format display text	409/422
Typed entry vs Excel with Indian regional settings	42/42

Dates (dd-mm), digit grouping (12,34,567) and currency follow the Windows regional settings, as Excel does on the same PC; files stay locale-independent.

What Dexterity Sheets does and does not do yet, feature by feature against official GridCraft and the latest Excel, is in docs/dexterity-parity-audit.md; the screen-by-screen check that nothing is a placeholder is docs/dexterity-ui-audit.md. How shared workbooks are kept intact (the blank-shared-workbook investigation, the sync states and the regression tests) is in docs/dexterity-p0-persistence.md; what is planned next, in docs/dexterity-roadmap.md.

An engine-first Rust workspace (from GridCraft) with Dexterity's layer on top:

Crate	Job
core, numfmt, formula, functions, model, calc, xlsx, chart, engine	the spreadsheet: values, number formats (now with regional settings), parser, 500+ functions, copy-on-write workbook model, dependency-graph recalculation, XLSX/CSV, charts, the command registry
ui-egui, apps/gridcraft	the Windows desktop app (DexteritySheets.exe)
collab	LAN co-authoring: workbook diff/patch, the wire protocol, client, server, discovery, accounts, audit trail, versions, update distribution
apps/gridcraft-server	DexSheetsServer.exe: the server (as a Windows service), accounts CLI, GitHub release fetcher
apps/gridcraft-server-manager	DexSheetsServerManager.exe: the server's control panel (people, bulk import from a template, service, firewall, updates, backups)
ui-egui/src/collab_ui.rs	everything sharing looks like in the window

How live editing works. Each window compares its workbook with the last state it synchronised and sends the difference as a patch of absolute assignments (cells with their style, sheet settings key by key, the sheet list). Because patches come from comparing workbooks, every way of changing one (commands, paste, fill, sort, undo, scripts) is shared without per-feature code. The server numbers each patch, writes it to an append-only log (fsync), records the audit lines, and broadcasts it. Every window shows server state + its own not-yet-acknowledged patches, so all copies converge on the server's order. Remote patches are also applied to each window's undo history, which is why Undo only takes back your own edits.

Every 6 hours the Upstream sync workflow checks storytold/gridcraft and, when there is something new:

1. Checks it's safe: it refuses if upstream rewrote its history or main is broken.
2. Merges into a candidate, never straight into main. Dexterity's files stay ours, branding is re-applied, and our small hooks into GridCraft's code are put back even when upstream moves code around (reapply_overlay.py, verified by check_overlay.py).
3. Tests that exact candidate: format, lint, every engine test, the collaboration tests, and three app windows editing one workbook live.
4. Builds and tries the installers: DexteritySheets-Setup.exe and the .msi are each installed, started, asked to calculate, and uninstalled; the server's DexSheetsServer-Setup.exe and .msi are installed as a running service, checked, and uninstalled.
5. Releases it (draft → upload → verify → publish), then refreshes this README, the screenshots, the demo animation and the website. Every PC is offered the update.
6. Anything that needs judgement becomes a pull request or an issue for a person. Nothing untested is ever released.

Details: packaging/dexterity/UPSTREAM.md. Versions: packaging/dexterity/VERSION is Dexterity Sheets'; Cargo.toml keeps GridCraft's.

RULES.md is binding for every change, by people, workflows or AI agents. What enforces it:

Guard	When	What it stops
Upstream sync	every 6 hours	GridCraft changes reaching users untested: each is merged on a candidate, fully tested, built and installer-tested before release
Excel watch (workflow)	daily	a new Microsoft Excel release going unnoticed: each one becomes an excel-release issue listing its Excel items, and with an ANTHROPIC_API_KEY secret an agent proposes the implementation as a pull request
Docs check (docs_check.py)	every push and PR	a user-visible change without a CHANGES.md line; the README or landing page naming a file a release doesn't ship; broken images and links; "coming soon" or placeholder text in the app
Performance gate (perf_gate.py, budgets)	every push and release	start-up, memory, idle CPU, typing, opening and scrolling a 2-million-cell file, memory given back after closing
Installer tests	every release	an installer that doesn't install, start, work and uninstall cleanly (app and server)

CHANGES.md is written once per change; the release notes, this README's "What's new" and the landing page are generated from it.

Rust 1.95+ with the MSVC toolchain; WiX 5 for the installer.

cargo build --release -p gridcraft -p gridcraft-server -p gridcraft-server-manager -p gridcraft-cli
#   target\release\DexteritySheets.exe         the app
#   target\release\DexSheetsServer.exe         the office server
#   target\release\DexSheetsServerManager.exe  its control panel
#   target\release\gridcraft-cli.exe     headless CLI (eval, convert, run commands)
pwsh packaging/windows/package.ps1 -Arch x64     # app and server Setup.exe + MSI, portable zip

Tests:

cargo test --release -p gridcraft-collab                         # patches, convergence, real TCP server
py -3 packaging/dexterity/tests/lan_e2e.py target/release        # 3 windows + server, 19 checks
py -3 packaging/dexterity/tests/update_e2e.py old.msi new.msi target/release/DexSheetsServer.exe work
py -3 packaging/dexterity/tests/installer_smoke.py dist 1.2.3   # both installers: install, start, uninstall
py -3 packaging/dexterity/tests/server_installer_smoke.py dist 1.2.3   # server installers (as administrator)
py -3 packaging/dexterity/tests/server_manager_shots.py target/release media   # Server Manager screenshots
py -3 packaging/dexterity/tests/screenshots.py target/release    # regenerates docs/images + demo frames
py -3 packaging/dexterity/make_demo.py                           # docs/readme/demo.webp from the frames

License and credits

Dexterity Sheets is built from GridCraft by the ArtCraft team and contributors, dual-licensed under MIT or Apache-2.0; notices in NOTICE, assets in ATTRIBUTION.md. Thank you to everyone who built GridCraft.

Dexterity Sheets is not affiliated with or endorsed by the ArtCraft team and ships none of its trademarks. Microsoft Excel is a trademark of Microsoft Corporation; Excel was used only as a black-box reference, and no Microsoft code, artwork or files are included.