Visimark MCP server

VisiMark

The numbers in your Markdown, checked on every commit.

Markdown is a fine way to write a document and a terrible way to keep its arithmetic honest. Change a 12 to a 20 in an invoice, forget the totals that depend on it, and the document still renders perfectly. GitHub does not complain. Your Markdown preview does not complain. A reviewer may not notice.

VisiMark makes those numbers verifiable. It turns the calculations in a document into explicit formulas, recomputes them, reports exactly what no longer agrees, and fails CI when a document contradicts its own arithmetic.

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 = Price * Qty is something an agent gets right, 50.00 is something it guesses. Write the formula instead of the number and the number stops being a claim and becomes a derivation — reviewable in a diff, re-runnable, enforceable in CI. The agent writes, VisiMark verifies, Git records the result.

A VisiMark document is an ordinary Markdown file. It renders correctly on GitHub, in VS Code preview, and through pandoc to both HTML and Word, today, with no plugin — verified, not assumed. What VisiMark adds is that every computed number in it carries the formula that produced it, that a machine can prove the two still agree, and that a change to either shows up as a small, readable diff.

A wrong invoice that renders clean

docs/example-invoice-drift.md is a real B2B invoice after someone raised the on-call hours from 12 to 20 and updated nothing that depends on it. It renders as a clean, plausible invoice on GitHub, in a Markdown preview, anywhere — which is the entire argument for this project. Every number in it carries the formula that produced it; the syntax follows further down. Here is visimark check reading the same file a reviewer just skimmed and approved:

$ visimark check docs/example-invoice-drift.md
docs/example-invoice-drift.md

  STALE   lines.Net       · On-call support         3120.00 ≠ 5200.00    Qty * Rate
  STALE   lines.VAT       · On-call support          717.60 ≠ 1196.00    Net * vat
  STALE   lines.Gross     · On-call support         3837.60 ≠ 6396.00    Net + VAT
  STALE   lines.Gross     · Discovery workshop      4428.50 ≠ 4428.00    Net + VAT
  STALE   lines.net_total                          23300.00 ≠ 25380.00   SUM(Net)
  STALE   lines.vat_total                           5359.00 ≠ 5837.40    SUM(VAT)
  STALE   lines.gross_total                        28659.00 ≠ 31217.40   SUM(Gross)
  STALE   lines.gross_total                        28659.00 ≠ 31217.40   SUM(Gross)
  STALE   schedule.Amount · Signature               8597.70 ≠ 9365.22    Share * lines.gross_total
  STALE   schedule.Amount · Delivery of backend    11463.60 ≠ 12486.96   Share * lines.gross_total
  STALE   schedule.Amount · Acceptance              8597.70 ≠ 9365.22    Share * lines.gross_total
  STALE   schedule.covered                         28659.00 ≠ 31217.40   SUM(Amount)
  STALE   terms.early_pay_total                    28085.82 ≠ 30593.05
  ST

Shortened. The full README is on GitHub.