@vantageos/mcp-architect

Turn any high-level requirement into a structured visual spec/plan with hierarchical drill-down. First ElPi Corp MCP App, built on the io.modelcontextprotocol/ui standard (stable 2026-01-26). Bilingual FR + EN.

About

Specs written as text walls are read once and abandoned. This MCP App makes them navigable.

@vantageos/mcp-architect is the first MCP App built on the io.modelcontextprotocol/ui standard (stable 2026-01-26). It decomposes any high-level requirement — a software system, a product plan, a process redesign — into a structured component tree your MCP client renders inline as an interactive drill-down. Clients without UI extension support receive the same data as clean, nested Markdown. No degradation either way.

What it does

Four tools with one shared mental model: decompose, visualize, drill deeper, export.

Every tool returns dual content: a ui:// resource for UI-capable clients and a fallback Markdown block for all others. This is non-negotiable — mandated by Critical Rule #1 of the MCP App standard.

Who it is for

• Software architects and lead developers decomposing complex requirements before sprint planning
• Product managers who need structured specs their teams can navigate, not documents they have to search
• Technical teams running MCP-capable clients (Claude Desktop, VS Code Insiders, MCPJam, ChatGPT MCP) who want visual output instead of prose

Why this is different

No other MCP server returns an interactive UI component alongside its text output. This is the first implementation of io.modelcontextprotocol/ui (stable since 2026-01-26) as a shipped, tested product — not a demo. The UI bundle is 68 KB gzipped, WCAG AA compliant, and contains zero external runtime calls.

Quick Start

npx -y @vantageos/mcp-architect

Add to mcp.json:

{
  "mcpServers": {
    "vantage-architect": {
      "command": "npx",
      "args": ["-y", "@vantageos/mcp-architect"]
    }
  }
}

No API key. No account. Then ask: "Decompose the architecture of a multi-tenant SaaS with real-time collaboration."

Examples

Software architecture: Call decompose_spec with a microservices requirement at depth: 3. Get a tree with components, modules, and tasks. Click any node to expand it via expand_node.

Product planning: Use domain: "product" to break a product brief into features, dependencies, and open decisions — each node typed (feature, task, decision).

Export to Mermaid: Call export_spec with format: "mermaid" to get a diagram you paste directly into your technical spec document.

Doctrine Flexibilité — Phase 1 / Phase 2

Phase 1 (current): stdio transport, local install, single-file UI bundle (68 KB gzipped), no remote server, no auth required. Phase 2 (planned): Remote MCP App demo via Railway, Pro tier, auth via Polar.sh. railway.json committed in repo for future activation. Activated based on adoption signal.

MIT License — Author: ElPi Corp / Laurent Perello — Source: github.com/elpiarthera/vantage-architect-mcp

Why

Specs and plans are usually returned as a wall of text. This MCP App returns them as an interactive component tree your client renders inline (Claude desktop, ChatGPT MCP, VS Code Insiders, MCPJam, …) with drill-down on every node. Clients without UI extension support fall back to a meaningful Markdown rendering — same data, no degradation.

Install

npx -y @vantageos/mcp-architect

Or in your mcp.json :

{
  "mcpServers": {
    "vantage-architect": {
      "command": "npx",
      "args": ["-y", "@vantageos/mcp-architect"]
    }
  }
}

Tools

Every tool returns dual content : a fallback markdown block + a ui:// resource (Critical Rule #1, no exception).

Quick example

await client.callTool("decompose_spec", {
  requirement: "Build a multi-tenant document collaboration SaaS with real-time editing, comments, history.",
  domain: "software",
  depth: 3,
  locale: "en"
});

In a UI-capable client, you get an interactive tree. In a plain text client, you get :

- **Build a multi-tenant document collaboration SaaS …** _(component)_ — Build …
  - **Frontend** _(module)_ — Frontend — auto-decomposition (heuristic v1.0).
    - …

Bilingual

Pass locale: "fr" to receive French node names + descriptions ; the UI also exposes a runtime EN/FR toggle (no localStorage, sandbox-safe).

Development

npm install
npm test          # 26 tests across 10 files (16 server + 8 component + 1 integration + 1 a11y)
npm run build     # server bundle (tsup)
npm run build:ui  # UI single-file bundle (vite + vite-plugin-singlefile)
npm run evals     # run evals/evals.json (16 cases)

Build & evals order

Run npm run build before npm run evals (or rely on the tsx fallback in scripts/run-evals.js). The evals harness imports built artifacts when present and falls back to live TS execution via tsx otherwise.

Standards & doctrine

• MCP server standard : ElPi Corp mcp-standard.md v1.
• MCP App standard : ElPi Corp mcp-app-standard.md v1 (10 Critical Rules).
• UI extension : io.modelcontextprotocol/ui stable 2026-01-26.
• Doctrine Flexibilité 5/5 : two alternatives documented in docs/architecture.md (Next.js web app ; Markdown export).

License

MIT © 2026 ElPi Corp / Laurent Perello

Built by: mcp-server-builder + mcp-apps-ui-builder (via gamma) | bu-mcp BU | 2026-04-26