Renders Mermaid diagrams as interactive viewers inside Claude Desktop, VS Code, and other MCP clients. Supports 13 diagram types including flowcharts, sequence diagrams, class diagrams, Gantt charts, and ER diagrams. The viewer includes pan and zoom controls plus a split-view source editor where you can modify diagram code and send it back to the LLM to continue the conversation with your changes. Context auto-syncs as you type so Claude always sees your latest edits. Useful when you need to iterate on diagrams collaboratively with the AI rather than copying Mermaid syntax back and forth. Install via .mcpb extension bundle or run through npx with stdio transport.
claude mcp add --transport stdio finfin-mermaid-mcp-app uvx mermaid-mcp-app