breaking-apart-systems

To decompose a vague system description into a formal architecture, this Skill guides you through a C4-based decomposition flow, breaking down the system into Container and Component levels with gated approvals at each step.

Generate Mermaid C4 diagrams from a design document by invoking the decomposition flow, which creates a companion file named design-doc-name-c4-diagrams.md to host all the generated architecture diagrams.

You need C4 architecture decomposition when formalizing architecture after a design document review, when internal structure is unclear, or when planning milestones that require explicit container and component diagrams.

Integrate C4 architecture diagrams back into a design plan by linking the generated decomposition outcomes and decisions directly into the source design document's Plan section, ensuring traceability with project milestones.

No, you cannot use this flow without a design document, because the process requires reading a source design document to generate the companion Mermaid diagram files and integrate the decomposition outcomes back into the Plan section.

The best way to formalize system architecture after a design review is using a gated C4 decomposition flow that breaks the system down level-by-level and integrates the resulting Mermaid diagrams directly into your design plan.