GolemUI MCP

What it does

GolemUI is a form library where a form is a JSON object (a list of widgets plus optional named states) or the TypeScript code that builds one through its fluent gui.* API. The @golemui/gui-mcp package runs a local stdio server, golemui-mcp, so a coding assistant can check its GolemUI output before handing it to the user. One wrong property name breaks a GolemUI form at runtime.

It serves two routes. On the JSON route it checks a definition against the JSON Schemas bundled in the package, returns errors with JSON Pointer paths and suggested fixes, and checks reactive `when` expressions for common mistakes. It can also build a form from a JSON Schema or from one OpenAPI 3.x operation, and it returns single-widget specs and guides to concepts such as states and the reactive scope. On the gui.* route it returns the full factory reference in one call and type-checks a code snippet against the real @golemui type declarations. On connect the server sends instructions that tell the assistant which route to take and to finish with the matching check.

The imports and render snippet in the gui.* reference follow the GOLEMUI_FRAMEWORK setting. In v2.0.0 the code accepts react, angular, vue, lit or vanilla and quietly uses react for any other value or when the setting is unset (src/dx/dx-specs.ts). The README does not list these values. The same binary also has validate-json and check-dx subcommands for CI or git hooks. Started with any argument at all, it runs as that CLI and exits rather than starting the server (src/cli.ts), so client configs must pass no extra arguments.

What it needs

Node.js with npx. The package is fetched from npm on first launch unless it is installed as a devDependency. It needs no account, API key or GolemUI service. It is only useful in a project that builds forms with GolemUI.

Limits

It only handles GolemUI forms: it does not render forms, run your app or change your files. It returns definitions and diagnostics as tool results. When generating from a JSON Schema, only local $ref is resolved, and anything the form cannot express is reported in diagnostics rather than mapped. OpenAPI generation reads one operation's JSON request body and falls back to its parameters when there is no object body. A GOLEMUI_FRAMEWORK value outside react, angular, vue, lit and vanilla falls back to react without an error.

Who it suits

It suits developers who have an assistant write GolemUI forms, in JSON or gui.* code, and want them checked against the library's real schemas and types before the code lands. It runs locally, has no sign-in, and reads only the input it is given, plus an OpenAPI URL if you pass one. It is of no use outside GolemUI projects. Teams on another form library need that library's own tooling.