Reference

Design MCP

Design MCP is the builder automation surface. It gives MCP clients structured access to app design, Cessy reference knowledge, validation, workspace changesets, page preview, and selected operations.

Endpoints

EndpointAuthority
/api/design-mcp-readonly?tenantId=<tenant-id>&appId=<app-id>App-scoped read-only inspection and reference access.
/api/design-mcp?tenantId=<tenant-id>&appId=<app-id>App-scoped full design access for trusted builder sessions.
/api/design-mcpTenant-wide API-key workflows and legacy automation.

Use the app-scoped endpoint whenever possible. It gives the MCP client the current app context and avoids tenant-wide ambiguity.

Auth

Design MCP supports bearer API keys and OAuth.

MethodUse
OAuthHuman builders in Claude, Codex, ChatGPT, or compatible MCP clients.
API keyCI, scripted migrations, and trusted automation.

Read-only Design MCP requires design:read or design. Full Design MCP requires design.

Tool families

Design MCP includes tools for:

  • reference knowledge
  • app and model introspection
  • workspace changesets
  • validation
  • task runs
  • page preview and browser QA
  • page design system inspection
  • testing
  • design resources
  • tool discovery
  • design changes
  • credentials, adapters, environments, permissions, and operational support where enabled

Tool availability can depend on endpoint, auth scope, app context, and server configuration.

Safe usage

For onboarding and review, connect read-only first. For mutation work, ask the agent to create or use a focused workspace, validate changes, and summarize impact before promotion.

Do not use Design MCP for normal runtime user workflows. Published app operation belongs to Runtime MCP or Runtime APIs.