Insights, tutorials, and updates about MCP Apps and ChatGPT Apps.
Run automated Playwright tests against real ChatGPT sessions to validate your Claude Connector or MCP App end-to-end. sunpeak handles auth, MCP server refresh, and iframe access so you only write assertions.
sunpeak now includes a local Claude inspector alongside ChatGPT. Test your MCP Apps in both hosts from a single dev server, switch between them with a dropdown, and ship to Claude and ChatGPT from one codebase.
Practical Claude Connector examples covering read-only data connectors, interactive UI connectors, CRUD connectors, API wrappers, and multi-resource connectors. Code patterns for each type with tool definitions, handlers, and resource components.
SSE transport is deprecated in the MCP spec. Learn how to migrate your Claude Connector from HTTP+SSE to Streamable HTTP, with code examples for the TypeScript SDK, Python SDK, and common hosting platforms.
How to deploy a Claude Connector to production. Covers hosting options (Cloudflare Workers, Vercel, Railway, VPS), HTTPS requirements, OAuth callback URLs, health checks, and going from local development to a live Claude integration.
Your Claude Connector is not working. Here is how to diagnose and fix the most common issues: connection failures, tools not called, UI not rendering, OAuth errors, token limits, and timeouts.
How to design MCP tools for your Claude Connector so Claude calls them correctly. Covers tool descriptions, Zod schemas, return types, granularity patterns, annotations, and common mistakes.
A developer guide to submitting your Claude Connector to the Connectors Directory. Covers tool annotations (the #1 rejection reason), privacy policies, OAuth callback URLs, documentation requirements, and how to test before you submit.
MCP App resources run in sandboxed iframes with no external connections by default. Learn the difference between connectDomains, resourceDomains, and frameDomains in your resource CSP, and when to use each one.
Set up a GitHub Actions workflow that runs unit tests and end-to-end Playwright tests for your MCP App on every push — no paid AI host accounts, no credits burned, no manual clicking.
Learn how TypeScript types flow through an MCP App from the Zod schema in your tool file to the useToolData generics in your React resource component. Covers Args inference, structuredContent typing, shared type files, inputPartial for streaming, and Vitest tool tests.
Step-by-step guide to deploying an MCP App to production with sunpeak. Covers sunpeak build, sunpeak start, authentication, environment variables, hosting options, and connecting your live server to ChatGPT and Claude.
MCP Apps can request their own display mode changes using useApp and requestDisplayMode. Learn how to add Expand, Pop Out, and Close buttons to your resources, handle the PiP-to-fullscreen fallback on mobile, and test every transition locally.
A developer guide to OAuth authentication for Claude Connectors. Learn when auth is required, how the OAuth flow works with Claude, how to configure callback URLs, and what the Connectors Directory submission requires.
Claude Connectors give Claude access to external data through MCP. Learn what data Claude can access, how authentication works, how to add custom connectors, and how to troubleshoot common issues like "could not load connectors directory."
The MCP Apps protocol sends tool-result, tool-cancelled, and tool-input notifications to your resource. Learn how to handle loading, error, and cancelled states in MCP App resources using sunpeak's useToolData hook, with complete UI patterns and simulation file examples for testing each state.
ChatGPT and Claude each have their own visual style. Use the host-provided CSS variables and useTheme to build MCP Apps that look native in any host, in both light and dark mode.
Most MCP App tutorials show read-only cards. useAppState lets you build interactive UIs where user actions sync back to the AI model. Here is how it works and when to use it.
Build an interactive Claude Connector from scratch. Learn the architecture, create tools and UI resources, test locally, connect to a real Claude session with ngrok, and submit to the Connectors Directory.
Build a working MCP App from scratch with sunpeak. This hands-on tutorial walks through creating a resource, writing a tool, adding test data, and running the multi-host inspector locally.
Claude Connectors connect Claude to external data sources. Claude Apps render interactive UI inside Claude. Both are built on MCP, but they solve different problems. Here is how they differ and how to build each.
ChatGPT and Claude both support MCP Apps. You can build a single React component that runs on both hosts without code changes. Here is how the cross-platform story works in practice.
Claude Apps are interactive applications that run inside Claude. They are MCP Apps built with React, rendered in sandboxed iframes, and portable across AI hosts. Here is how to build one.
Build a working ChatGPT App from scratch using sunpeak. This hands-on tutorial walks through creating a recipe card, adding mock data, and testing locally without a paid ChatGPT account.
Learn the MCP concepts behind MCP Apps: hosts, servers, Tools, and Resources, and how they combine to render interactive UI inside AI conversations.
A concrete proposal for building MCP Apps that work across ChatGPT, Claude, Goose, and VS Code. Covers the cross-host architecture decisions, what to keep portable, when to add host-specific code, and the build order that gets you there.
A concrete proposal for building a ChatGPT App from scratch: architecture, stack, local development, testing strategy, deployment, and the build order that gets you to production fastest.
MCP Apps and A2UI both solve agent UI problems, but in completely different ways. MCP Apps are coded web applications that run in AI conversations. A2UI is a declarative JSON protocol for agent-generated interfaces. Here is how to choose.
Custom GPTs and ChatGPT Apps both run inside ChatGPT, but they are built for completely different things. Custom GPTs are no-code text assistants. ChatGPT Apps are coded applications with interactive UI built on the Model Context Protocol.
MCP Apps are interactive UIs that run inside AI conversations on ChatGPT, Claude, and other hosts. Learn how MCP Apps work, how they differ from MCP servers, and how to build one with a working code example.
MCP Apps run inside ChatGPT, Claude, and other AI hosts. Picking the right MCP App framework determines how fast you ship, how well you test, and whether your app works across hosts. Here is what to look for.
sunpeak aligns its APIs around the MCP App standard while layering in ChatGPT and Claude-specific functionality as first-class citizens. MCP Apps now run in ChatGPT, Claude, Goose, and VS Code.
Learn how to debug ChatGPT Apps and MCP Apps with practical troubleshooting techniques. Covers common errors, display mode issues, tool invocation debugging, and ChatGPT App development tips using sunpeak.
Learn how to test ChatGPT Apps and MCP Apps with unit tests, end-to-end tests, and simulation files. Covers Vitest, Playwright, and CI/CD integration using the sunpeak ChatGPT App framework.
ChatGPT Apps are a new UI paradigm built on the Model Context Protocol (MCP). Building them from scratch means solving infrastructure problems every time. A ChatGPT App framework like sunpeak changes that.
A practical guide to minimizing AI-era tech debt through context window management, smaller teams, and emerging protocols like MCP and ChatGPT Apps. Given as a talk at the Austin CTO Club.
No need for a ChatGPT Plus subscription to build ChatGPT Apps. ChatGPT Apps are MCP Apps built on the Model Context Protocol. Here is how to develop locally with the sunpeak inspector.
A beginner-friendly guide to developing ChatGPT Apps on your local machine using sunpeak. ChatGPT Apps are MCP Apps built on the Model Context Protocol. No paid ChatGPT account required.
MCP has adoption, but the consumer experience is broken. Discovery, connection, and use all need browser-like simplicity—and ChatGPT Apps are the first step.
Build and deploy a ChatGPT App with just 2 commands using sunpeak. A quick-start guide to ChatGPT App development with MCP servers and ngrok deployment.
A comprehensive breakdown of ChatGPT App and MCP App display behavior across all Display Modes and screen widths. Learn about inline, fullscreen, and picture-in-picture modes for ChatGPT Apps.
A practical guide to building ChatGPT Apps (MCP Apps) based on real-world experience. Learn about MCP architecture, caching strategies, and undocumented runtime APIs for ChatGPT App development.
A complete guide to building ChatGPT Apps using the MCP Apps protocol. Covers official resources, project setup, architecture basics, display modes, testing, and how to submit to the ChatGPT App Directory.
