Cloudviz API vs draw.io + MCP

Cloudviz API

Diagrams come from the live AWS account through a read-only cross-account role with a per-customer external ID. AWS only, and API access starts at the $49 a month Team plan.

draw.io + MCP

Free, keyless and Apache 2.0, with a Docker image for self-hosting. Tool descriptions embed a 34.5 KB XML reference and a 14 KB Mermaid reference, roughly 13,000 tokens.

Cloudviz API

1. Call GET /aws/accounts/ first to get the Cloudviz account ID, then request /aws/accounts/{account-id}/{region}/{format}
2. On a 202, wait and repeat the same GET until the diagram is ready
3. Ask for jsonSnapshot or jsonDiagram (there is no plain json format) when the agent has to reason over resources
4. Use a read-only key unless the agent has to add, change or delete AWS accounts

draw.io + MCP

1. Pass mermaid to create_diagram for any type on its Mermaid list. Use xml only for icons, mockups or hand-placed layouts
2. Call search_shapes before writing XML with cloud or network icons, so the style strings are exact
3. Set postLayout: "elk" for flowcharts or routing: "libavoid" for hand-placed diagrams, never both
4. Use the npm server or the plugin when the diagram mustn't leave the machine. The hosted App sends it to draw.io's server
5. Expect the tool list to cost about 13,000 tokens before the first call