Review Mode

Use this mode to get a structured critique of an existing C4 diagram. The agent evaluates it against Simon Brown's official review checklist and the additional rules enforced by c4designer.

When it activates

• You paste an existing Mermaid / PlantUML / Structurizr diagram
• "Review this diagram", "Is this good?", "What's wrong with this?"
• "Explain what this diagram shows"

The checklist

The agent runs through:

Simon Brown's Official Checklist

• ✅ Does every diagram have a title?
• ✅ Is there a legend / key?
• ✅ Does every element have a description?
• ✅ Does every relationship have a label?
• ✅ Is the diagram consistent with other levels?
• ✅ Are acronyms and jargon explained?
• ✅ Is the scope appropriate for the target audience?

c4designer Additions

• ✅ Are all Rel labels descriptive (no "Uses", "Calls", "Reads")?
• ✅ Do all Container elements state their technology?
• ✅ Are all arrows unidirectional (no BiRel)?
• ✅ Are there any undefined aliases in Rel statements?
• ✅ Are boundaries using System_Boundary / Container_Boundary (not { appended to a container)?

Example

You:

Act as the C4 Designer in Review mode. Please critique this diagram:

[paste diagram]

Agent output:

## Review: Container Diagram for Payments Service

### Issues Found

🔴 **Critical**
- Line 12: `Rel(api, db, "Uses")` — bare "Uses" label is forbidden.
  Replace with a descriptive intent, e.g., "Reads payment records from".

🟡 **Warnings**
- The diagram has no title. Add `title Container diagram for Payments Service`.
- `Container(cache, "Redis")` — missing technology parameter.
  Should be `Container(cache, "Cache", "Redis 7", "Stores session tokens.")`.

🟢 **Good**
- All external systems are included.
- Relationships are unidirectional.

Getting an explanation instead of a critique

Act as the C4 Designer. Please explain what this diagram shows to a
non-technical stakeholder.

[paste diagram]

The agent will produce a plain-English narrative describing the architecture.