You can also bootstrap your initial schema with LLMs with the excalidraw MCP "app" [0]. But MCP "apps"[1] are quite new and not very well supported yet.
I didn't have good experience with excalidraw-mcp when it first came out a month ago; the Claude-generated diagrams were too raw/unpolished. I'm sticking to mermaid for now but I'm interested in hearing how people make exclidraw-mcp work for them