Graphviz DOT Diagram Generator
Important: Use
```dotas the code fence identifier, NOT```graphviz.
Quick Start: Choose digraph (directed) or graph (undirected) → Define nodes with attributes (shape, color, label) → Connect with -> or -- → Set layout (rankdir, spacing) → Wrap in ```dot fence. Default: top-to-bottom (rankdir=TB), cluster names must start with cluster_, use semicolons.
Critical Syntax Rules
Rule 1: Cluster Naming
❌ subgraph backend { } → Won't render as box ✅ subgraph cluster_backend { } → Must start with cluster_
Rule 2: Node IDs with Spaces
❌ API Gateway [label="API"]; → Invalid ID ✅ "API Gateway" [label="API"]; → Quote the ID ✅ api_gateway [label="API Gateway"]; → Use underscore ID
Rule 3: Edge Syntax Difference
digraph: A -> B; → Directed arrow graph: A -- B; → Undirected line
Rule 4: Attribute Syntax
❌ node [shape=box color=red] → Missing comma ✅ node [shape=box, color=red]; → Comma separated
Rule 5: HTML Labels
✅ shape=plaintext for HTML labels ✅ Use < > not " " for HTML content
Common Pitfalls
| Issue | Solution |
|---|---|
| Nodes overlapping | Increase nodesep and ranksep |
| Poor layout | Change rankdir or add {rank=same} |
| Edges crossing | Use splines=ortho or adjust node order |
| Cluster not showing | Name must start with cluster_ |
| Label not displaying | Check quote escaping |
Output Format
markdown```dot digraph G { [diagram code] } ```
Related Files
For advanced layout control and complex styling, refer to references below:
- syntax.md — Layout control (rankdir, splines, rank), HTML labels, edge styles, cluster subgraphs, and record-based nodes
