Juris MCP Server
The central hub of the YAML-driven UI platform. Parses YAML component specs and generates live HTML preview pages using the Juris.js reactive runtime — no build step, no compilation. Components are interpreted directly in the browser.
Stack: Node.js · ES modules · Juris.js runtime · Hono · MCP SDK
Port: 3005 (REST + runtime file serving)
MCP Tools
generate_preview— generates a live HTML page from a YAML spec; runs in the browser via runtime interpretationvalidate_yaml— validates YAML syntax before preview generation
MCP Resources
juris://manifest— server capabilitiesjuris://components— full component registry (17 components)juris://labels— text substitution dictionaryjuris://help— usage documentationjuris://runtime/*— individual runtime JS files served on demand
Component Registry
17 components in the live Juris registry (counted from juris-mcp-server source, 2026-08-10). Lit and Stencil export registries mirror each other at 14 components each; see docs/component-parity-assessment.md for the parity matrix.
| Namespace | Focus | Count |
|---|---|---|
ds |
Design system primitives (switch, input, icon-toggle, info-badge) | 4 |
md |
Material Design 3 components (icon, button, card, icon-button, toggle-icon, toggle) | 6 |
layout |
Page and grid structures (flex, grid) | 2 |
marketing |
Landing page / content blocks (hero, cta) | 2 |
custom |
widget | 1 |
| (unprefixed) | div, repeat | 2 |
Role in the Platform
Juris is the prototyping layer. Where Lit and Stencil require a compilation pipeline, Juris gives immediate visual feedback from a YAML spec — critical for rapid iteration. The runtime files it serves at /runtime/{filename} are also consumed by the preview pages generated by the other servers.
Also used as the underlying runtime for sudoku-juris, the standalone proof-of-concept that validated Juris as a capable reactive runtime outside the YAML platform context.
See research-yaml-platform for platform architecture.