Diagramming Code skill: what it does and how to install it

What it does. Analyses a codebase with Trailmark, selects a diagram type and generates Mermaid output from the parsed graph. It supports call graphs, class hierarchies, module dependencies, class containment, complexity heatmaps and data-flow visualisations, using Trailmark's native command when available or a bundled script.

When to use it. For visualising code architecture, call paths, complexity hotspots or data flows to sensitive functions. It is not intended for graph queries without diagrams, mutation testing triage or architecture diagrams that are not derived from code.