The Diametric Safety Case Manager is a desktop app for building safety cases: goal structuring notation, hazard bow ties, risk registers, FMEAs. It was a commercial product written in Haskell with a GTK interface, and was open-sourced when Diametric closed down in 2022.

This is that app running in your browser. All 41,280 lines of the Haskell Diagram Editing System (HADES) were ported one module at a time to TypeScript, keeping the original names, behaviour and look. GTK became a small web toolkit built on React and Radix, and Cairo/Pango drawing goes to a canvas.

Open it full screen →

Things to try

• Double-click a diagram in the tree on the right, then drag boxes around, double-click one to edit it, and undo with Ctrl+Z.
• Hazard Log → Bow Tie Analysis → BowTie Diagram has a hazard bow tie with controls pegged onto the threat lines.
• Your browser’s back and forward buttons move between the diagrams you’ve opened. In the embedded version above that means they navigate the frame, not this page. Weird, as promised.
• File → Open takes any .dsm file, and File → Save hands you one back. You can also drop a file onto the window.

The launch video

The source is at Daspy11/hades-web.