Elysia MCP Adapter — routes become protocol

Build a complete HTML document, then connect a tool to its ui:// resource:

import {
  MCP_APPS_RESOURCE_MIME_TYPE,
  mcp
} from '@mwillbanks/elysia-mcp-adapter'

const uri = 'ui://dashboard/index.html'

app
  .use(mcp({ allowedRoutes: [], extensions: { apps: {} } }))
  .mcpTool('dashboard.open', loadDashboard, {
    app: { resourceUri: uri, visibility: ['model', 'app'] }
  })
  .mcpResource(uri, () => ({
    contents: [{ uri, mimeType: MCP_APPS_RESOURCE_MIME_TYPE, text: html }]
  }), {
    mimeType: MCP_APPS_RESOURCE_MIME_TYPE,
    app: {
      csp: { connectDomains: [], resourceDomains: [] },
      prefersBorder: true
    }
  })

Return meaningful content and structuredContent from the launch tool so non-Apps clients can still complete the task. Start with the repository's dependency-free browser vanilla example.

Apps quick start