Kroki-MCP

What is Kroki-MCP?

Kroki-MCP is a command-line tool and MCP (Model Context Protocol) server that converts textual diagrams – like PlantUML and Mermaid – into images using a Kroki backend. It supports both local and remote Kroki servers and offers flexible configuration with multiple output formats. It is intended for developers and teams who want to generate diagram images programmatically or integrate diagram generation into MCP-aware environments.

How to use Kroki-MCP?

Kroki-MCP is installed and run via the Go toolchain or Docker. Invoke it with kroki-mcp and specify output format (--format), mode (--mode, either sse or stdio), and Kroki host (--kroki-host). To use it as an MCP server, add a configuration entry in your MCP client’s settings file (e.g., claude_desktop_config.json) pointing to the kroki-mcp command with appropriate arguments.

Key features of Kroki-MCP

• Two operation modes: SSE (server-sent events) and STDIO (stdin/stdout)
• Output formats: PNG (default), SVG, JPEG, and PDF
• Configurable Kroki backend host (default: https://kroki.io)
• Extensible design for additional diagram types and formats
• MCP integration via github.com/mark3labs/mcp-go
• Supports both local and remote Kroki servers

Use cases of Kroki-MCP

• Convert text-based diagrams (e.g., PlantUML, Mermaid) to images in CI/CD pipelines
• Provide diagram generation as an MCP tool within MCP-aware assistants or editors
• Render diagrams from source code repositories for documentation previews
• Test diagram rendering by pointing to a local Kroki server in a Docker development environment

FAQ from Kroki-MCP

What transports does Kroki-MCP support?

Kroki-MCP supports two transports: SSE (Server-Sent Events) and STDIO (standard input/output). The default mode is STDIO.

What output formats are available?

Supported output formats are PNG (default), SVG, JPEG, and PDF. Use the --format flag to choose one.

Can I use a local Kroki server instead of the public one?

Yes. Use the --kroki-host flag to specify a custom Kroki server URL. For example, --kroki-host http://localhost:8000.

How do I run Kroki-MCP inside an MCP client?

Add a kroki-mcp entry to your MCP client’s configuration file, specifying the command (e.g., go or the binary path) and args including run, the module path, -m stdio, -f png, and --kroki-host. Example configuration is provided in the README.

What are the runtime dependencies?

Kroki-MCP requires Go 1.22 or later to build/run from source. A Dockerfile and docker-compose.yml are provided for containerized development and deployment. No additional runtime dependencies are mentioned beyond these and the network access to a Kroki server.