Integration surface
MCP server
Designesy design intelligence over the Model Context Protocol: seventeen tools, one endpoint, one MCP App, no wrapper.
The Designesy MCP server runs natively on the same Vercel project as this site. It speaks the 2026-07-28 Streamable HTTP spec: stateless, no sessions, no handshake. Any MCP-compatible client can connect.
Endpoint
https://www.designesy.org/api/mcp
Transport
Streamable HTTP · POST · JSON or SSE response · stateless
Registry
io.github.LE-VAI/designesy-org on registry.modelcontextprotocol.io
Published on the MCP Registry
Discoverable by any MCP-compatible client. Search designesy on the registry or connect directly.
Conformance
WCAG 2.2 AA
0 violations
axe-core 4.12.1, automated rules for WCAG 2.0 and 2.1 at A and AA, and 2.2 at AA · 70 pages, light and dark · measured 2026-10-11
DTCG 2025.10
100 A
/export/dtcg · 9 of 10 checks pass, 1 does not apply (t07: no custom types) · designesy_tokens_score, 2026-10-11
Contract score
100 A
45-check engine 1.3.0 · 38 PASS / 0 FAIL / 3 WARN / 0 SKIP / 4 MANUAL · scored 2026-10-12
Tools
Seven read-only tools fetch public machine exports from designesy.org. Nine executable tools run live verification: the 45-check score engine, DTCG token validation, Lottie motion validation, drift scoring, AI-readiness scoring, guardrails generation, monitor scoring, design-system comparison, and the composite report. One accessibility framework provides the WCAG 2.2 Playwright + axe-core script template. All tools return JSON.
Client configuration
Copy-paste the config for your client. Most modern clients support Streamable HTTP natively: just point them at the endpoint. For stdio-only clients, use the mcp-remote bridge.
Claude Code (CLI)
- .mcp.json (project root, shared)
- ~/.claude.json (your own; claude mcp add writes here for this project, add --scope user for every project)
{
"mcpServers": {
"designesy": {
"type": "http",
"url": "https://www.designesy.org/api/mcp"
}
}
}Claude Code (the CLI agent) supports Streamable HTTP natively via type: "http". Or skip the JSON: claude mcp add --transport http designesy https://www.designesy.org/api/mcp. This is separate from Claude Desktop (below).
Cursor
- .cursor/mcp.json (project) or ~/.cursor/mcp.json (global)
{
"mcpServers": {
"designesy": {
"url": "https://www.designesy.org/api/mcp"
}
}
}Cursor supports Streamable HTTP directly: just provide url. It auto-detects HTTP vs SSE. No type field needed.
ZCode
- .zcode MCP config (User or Workspace scope)
{
"mcpServers": {
"designesy": {
"url": "https://www.designesy.org/api/mcp"
}
}
}ZCode supports HTTP, SSE, and stdio. Add via Settings → MCP Servers (type: HTTP), or paste this JSON in full config mode.
VS Code + Copilot
- .vscode/mcp.json
{
"servers": {
"designesy": {
"type": "http",
"url": "https://www.designesy.org/api/mcp"
}
}
}VS Code with GitHub Copilot supports HTTP MCP servers. Note: key is "servers", not "mcpServers". VS Code tries HTTP Stream first, falls back to SSE.
Claude Desktop (stdio-only; needs the mcp-remote bridge)
- ~/Library/Application Support/Claude/claude_desktop_config.json (macOS)
- %APPDATA%\Claude\claude_desktop_config.json (Windows)
{
"mcpServers": {
"designesy": {
"command": "npx",
"args": ["mcp-remote@latest", "https://www.designesy.org/api/mcp"]
}
}
}Claude Desktop's JSON config is stdio-only: a url field silently deletes the entire mcpServers block (bug #37286). Use the mcp-remote npm package as a stdio bridge. Alternatively, add the server via Settings → Connectors → Add custom connector (no JSON editing, supports public HTTPS directly).
How it works
Runtime
Vercel Node.js serverless · mcp-handler 2.x (Vercel's official MCP adapter) · @modelcontextprotocol/server (SDK v2) · Zod 4 · stateless 2026-07-28 spec native · 300-second max duration (Pro Plan)
Caching
5-minute in-memory cache on read-only tools. Vercel Fluid Compute reuses warm instances, so cache hits are common. The tools that score a URL (designesy_score, drift, readiness, guardrails, monitor, compare and report) call the site's own engines, which cache each result for 24 hours per URL. A designesy_score receipt carries retrieved_at, the time the page was read.
No Python
The server is native TypeScript. It runs in the same Vercel runtime as this site, with no child processes, no mcp-proxy bridge, and no external dependencies beyond the MCP SDK.
The seven read-only tools fetch the same public machine exports that any HTTP client can fetch directly. The MCP server adds structured tool schemas, Zod validation, and a single public endpoint with no key or sign-in, useful for agents that prefer the MCP protocol over raw HTTP.
Quick test
Verify the endpoint is live with a single curl:
curl -X POST https://www.designesy.org/api/mcp \
-H "Content-Type: application/json" \
-H "Accept: application/json, text/event-stream" \
-d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}'The response is one server-sent event carrying a JSON-RPC 2.0 result that lists all seventeen tools with their schemas. The Accept header must name both types; without it the endpoint answers HTTP 406.