VisiMark for VS Code
The numbers in your Markdown, checked on every commit.
VisiMark makes calculations explicit, changes reviewable, and numerical
correctness enforceable — while keeping the document as plain Markdown. This
extension is where that starts: the wrong number is squiggled as you type, and
gone by the time you save.
The problem, in four lines
Someone raised the on-call hours from 12 to 20 and updated nothing that
depends on it. The table still renders perfectly. GitHub does not complain.
Your Markdown preview does not complain. A reviewer may not notice.
| Item | Qty | Rate | Net |
|--------------------|----:|-------:|--------:|
| Discovery workshop | 2 |1800.00 | 3600.00 |
| On-call support | 20 | 260.00 | 3120.00 |
```vmark #lines
Net = Qty * Rate
net_total = SUM(Net)
```
Net of tax the engagement comes to **6720.00**<!--vmark=lines.net_total--> PLN.
VisiMark complains. In the editor, 3120.00 and 6720.00 are squiggled, each
with the value it should hold shown beside it, and the status bar reads
VisiMark: 3 stale. The same document through the CLI, in CI:
$ visimark check invoice.md
STALE lines.Net · On-call support 3120.00 ≠ 5200.00 Qty * Rate
STALE lines.net_total 6720.00 ≠ 8800.00 SUM(Net)
STALE 1 prose anchors bound to the values above
3 problems (3 stale, 0 errors)
Note the last line: the bolded total in the prose is bound to the formula
too, and drifts with it.
In the editor
Live checking. Stale values, ambiguous dates, mixed units, unknown names
and circular definitions are squiggled as you type. Nothing is written.
Inline truth. A stale value shows what it should be, right beside it,
without the file changing.
Repair. Every stale value is brought up to date when you save — only the
computed cells and anchored values, never your prose or input columns. Also
on demand, as Fix All Stale Values, a Quick Fix on one cell, or "Format
Document". Turn off visimark.format.fixOnSave to keep it strictly manual;
autosave never triggers it.
Hover. Over a computed cell: the formula behind it, what it depends on,
and — if it is stale — what it computes versus what the cell says. Over a
function name: signature, parameters, return type, precision, rounding, and
the errors it can raise.
Explain. Every sheet in the document as a plain-text summary — inputs,
rules, and the order they evaluate in. What a reviewer reads instead of
re-deriving the arithmetic by hand:
#lines
inputs: Item, Qty, Rate
rules:
Net = Qty * Rate precision 2 (derived)
scalars:
net_total = SUM(Net) precision 2 (derived)
order: Net → net_total
A lens on every block reading 2 formulas · 2 stale, one click from
fixing that sheet or explaining it.
Quick fixes for the rest: rewrite an unambiguous date to ISO, wrap a
column reference in SUM(...), correct a misspelled name.
Written by an agent, checked by a machine
This matters most when the Markdown is written or edited by an AI agent.
Agents are reliable at writing formulas and unreliable at the arithmetic those
formulas describe: Net = Qty * Rate is something an agent gets right,
5200.00 is something it guesses. Write the formula instead of the number and
the number stops being a claim and becomes a derivation — visible in the
editor, readable in a diff, and enforceable in CI by the same engine.
Getting started
Open any Markdown file and add a vmark block. There is nothing to install
and nothing to configure — the engine ships inside the extension, no separate
runtime, no node_modules, no project setup. To fail a build on a document
that contradicts itself, add visimark check to CI.
Commands: Fix All Stale Values · Fix Sheet · Explain Sheet · Show Report ·
Restart Server.
Settings: visimark.enable, visimark.format.fixOnSave,
visimark.format.fixDates, visimark.inlayHints.enable,
visimark.codeLens.enable, visimark.statusBar.enable.
A VisiMark document is ordinary Markdown. It renders correctly on GitHub, in
VS Code preview, and through pandoc to both HTML and Word, with no plugin.
Documentation and the CLI →
