build-mcp-apps

name	build-mcp-apps
description	Guide developers through creating and updating MCP servers, MCP apps, and ChatGPT apps with Skybridge. Covers brainstorming, bootstrapping, implementing tools/views, debugging, running dev servers, and preparing apps for deployment. Use when a user wants to create or update a ChatGPT app, MCP app, MCP server, or use the Skybridge framework.

Building MCP Apps

MCP apps are conversational experiences that extend AI assistants through tools and custom UI views. They are built as MCP servers invoked during conversations.

Important: The app is consumed by two users at once: the human and the AI Assistant LLM. They collaborate through the view-the human interacts with it, the LLM sees its state. Internalize this before writing code: the view is your shared surface.

Skybridge docs are the product source of truth. Use this skill's references for agent workflow, and use https://docs.skybridge.tech/ for canonical framework behavior and API details.

SPEC.md keeps track of the app's requirements and design decisions. Keep it up to date as you work on the app.

No SPEC.md? -> Read discover.md first. Nothing else until SPEC.md exists.

SPEC.md exists? -> Read SPEC.md, then follow architecture.md to design the change. Update SPEC.md, then read the relevant Implementation references below before writing code.

Setup

1. Copy template -> copy-template.md: when starting a new project with ready SPEC.md
2. Run locally -> run-locally.md: when ready to test, need dev server, use devtools to render views, or connect to ChatGPT/Claude
3. Use DevTools UI -> devtools.md: when testing tools/views through Skybridge DevTools, opening the Alpic playground, starting a tunnel, or deploying from the DevTools UI

Architecture

Design or evolve UX flows and API shape -> architecture.md

Implementation

• Fetch and render data -> fetch-and-render-data.md: when implementing server handlers and view data fetching
• State and context -> state-and-context.md: when persisting view UI state and updating LLM context
• Prompt LLM -> prompt-llm.md: when view needs to trigger LLM response
• UI guidelines -> ui-guidelines.md: display modes, layout constraints, theme, device, and locale
• External links -> open-external-links.md: when redirecting to external URLs or setting "open in app" target
• Download file -> download-file.md: when saving content to the user's filesystem
• OAuth -> oauth.md: when tools need user authentication to access user-specific data
• CSP -> csp.md: when declaring allowed domains for fetch, assets, redirects, or iframes
• Hosting assets -> hosting-assets.md: when a ChatGPT/MCP app needs static JS, CSS, images, or built UI assets hosted on Alpic

Deploy

• Prepare for production -> deploy.md: when the app is ready and needs a deployment handoff to use-alpic
• Publish to app directories -> publish.md: when ready to submit for review

Skybridge Docs

• Docs home: https://docs.skybridge.tech/
• Full API reference: https://docs.skybridge.tech/api-reference.md
• Use the API reference when implementing server APIs, tools, views, resources, UI context, or SDK behavior that is not fully specified in these local references.