COMPLETE PLUGIN
View an example
Example installation for MCP
Example session using the verified commands above.
This skill provides guidance for building MCP Apps, the official io.modelcontextprotocol/ui extension for interactive HTML interfaces inside MCP hosts. This skill should be used when the user asks to "create an MCP App", "add UI to an MCP tool", "build interactive MCP", "ui:// resource", "sandboxed iframe MCP", "interactive chat UI", "embed UI in chat", "MCP tool with interface", or needs capability negotiation, resource CSP, app-only tools, host lifecycle, or progressive text fallbacks.

Install the complete plugin to include its agents, hooks, commands, and runtime context.
Fastest path: hand this line to the coding agent doing the setup. It reads this page and installs the MCP plugin, which ships this skill with everything it relies on.
Click anywhere on the prompt to copy.
Choose a runtime, then follow its setup steps. This installs the complete MCP plugin.
COMPLETE PLUGIN
Example session using the verified commands above.
The portable SKILL.md on its own, without the plugin’s hooks, agents, commands, and companion skills. Use it only when you intentionally want the narrower path.
No required companion skills are declared.

Agent architecture specialist. Use this agent when the user asks to "design an agent", "wire up tool-calling", "add memory to my agent", "set up agent routing", "implement delegated signup", "support auth.md", or "integrate ID-JAG". Covers evals, resilient chat UIs, and delegated agent auth. Not for deploying a built agent to hosting or wiring its cron and sandbox (use devops), authoring individual skills or commands (use prompt-engineer), or auditing skill accuracy (use trainer).

UI and interface design agent. Use this agent when the user asks to "design a component", "create UI", "style a page", "set up shadcn", "implement dark mode", "review UI accessibility", "create a mockup", "design a game HUD", "build a TV app interface", or "add controller navigation". Covers design systems, ten-foot UI, and Pencil mockups. Not for performance work (use optimizer) or 3D scenes (use creative-developer).

Creative 3D web developer for Three.js and React Three Fiber, including diegetic and world-space UI. Use this agent when the user asks to "create a 3D scene", "build a Three.js demo", "write a shader", "add physics to a scene", "build a WebGL prototype", or "optimize 3D performance". Covers R3F, Drei, GLSL, TSL, and 3D asset pipelines. Not for 2D interface design (use designer).

MCP specialist. Use this agent when the user asks to "set up an MCP server", "build an MCP App", "connect Claude Code to my database via MCP", "fix this MCP connection error", or "publish my MCP server to npm". Covers MCP Apps, JSON Render, PostgreSQL/Redis/MongoDB/GitHub/Vercel servers, and the Tool Search Tool. Not for general third-party API integrations (use integration-expert) or agent tool-calling logic (use agent-builder).

Third-party service integration specialist. Use this agent when the user asks to "wire up this webhook", "integrate with this API", "sync data from X on a schedule", or "send transactional emails" — with signature verification, rate limiting, and error handling. Not for money-movement integrations (use payments) or MCP server setup (use mcp).
Pass the canonical page to a teammate or keep it close for later.
This skill should be used when tracking API spend, analyzing billing data, monitoring service costs, running budget reports, or optimizing agent spend across Anthropic, Vercel, Railway, and other platforms. Invoke when asked about "cost tracking", "billing analysis", "spend report", "API costs", "usage monitoring", "budget vs actual", "cost optimization", or "which agents cost the most".