Requirement Diagram

Mermaid Studio provides language support for SysML-style requirement diagrams inside IntelliJ IDEA and other JetBrains IDEs. Requirement diagrams document and visualize system requirements, their relationships, and how they are satisfied by design elements, which is valuable for requirements traceability in engineering projects.

Syntax Highlighting

Syntax highlighting integrates directly with IntelliJ’s color scheme system, so diagram colors always match your editor theme.

Armada Dark

Islands Dark

Islands Light

IDE Support

Requirement diagrams have full IDE support:

• Syntax highlighting - Color-coded requirements, elements, and relationships
• Code completion - Suggestions for requirement types and verification methods. Relationship-type completion in the verb slot is a plain text list (no leading icon), so it doesn’t visually compete with the other identifier completions.
• Live templates - 15 abbreviations covering the six requirement variants, element blocks, and the seven relationship verbs (plus a generic verb-picker).
• Refactoring - Rename requirements and elements across the diagram
• Find usages - Track where requirements are referenced
• Code Vision - See relationship counts at a glance
• Color provider - Preview and pick colors for styling
• Navigation bar - Quick access to requirements in large documents
• Structure view - Hierarchical overview of requirements
• Code folding - Collapse requirement definitions
• Formatting - Auto-format your diagram code
• Inspections - Detect undefined references and missing properties
• Brace matching - Navigate between requirement boundaries

Live templates

A set of 15 context-aware live templates scaffolds the six requirement variants, element blocks, and the seven relationship verbs. Type a short abbreviation, accept it from the completion popup, and tab through the template variables.

Individual abbreviations can be toggled under Settings > Tools > Mermaid Studio > Live Templates in the Requirement Diagram group. See Live Templates for the cross-cutting mechanics (triggering, contextual visibility, configuration).

Requirement declarations

The six requirement-variant templates share the same body shape (id, text, risk, verifymethod). risk and verifymethod are populated from enum() pickers, so Tab walks you through valid values.

Abbreviation	Expansion
req	Generic requirement declaration
reqf	functionalRequirement
reqi	interfaceRequirement
reqperf	performanceRequirement
reqphy	physicalRequirement
reqdc	designConstraint

Elements

Abbreviation	Expansion
elem	element declaration with type and docRef

Relationships

The generic rel template uses a verb picker so you can choose any of the seven relationship verbs on insert. The seven hard-coded templates pre-pick the verb for you.

Abbreviation	Expansion
rel	Relationship with verb picker
rels	satisfies relationship
relt	traces relationship
relc	contains relationship
reld	derives relationship
relr	refines relationship
relcp	copies relationship
relv	verifies relationship

Quick Syntax Reference

Requirement types:

• requirement - Functional requirement
• functionalRequirement - Functional requirement (explicit)
• performanceRequirement - Performance constraint
• interfaceRequirement - Interface specification
• physicalRequirement - Physical constraint
• designConstraint - Design limitation

Requirement properties:

requirementDiagram
    requirement Example {
        id: REQ-002
        text: Description of the requirement
        risk: low
        verifymethod: analysis
    }

Risk levels: low, medium, high

Verification methods: analysis, inspection, test, demonstration

Relationship types:

• - satisfies -> - Element satisfies requirement
• - traces -> - Requirement traces to another
• - contains -> - Requirement contains sub-requirements
• - derives -> - Requirement derives from another
• - refines -> - Requirement refines another
• - copies -> - Requirement copies another
• - verifies -> - Element verifies requirement

For the complete syntax reference, see the Mermaid.js Requirement Diagram documentation.