Sunpeak MCP Framework
Server-agnostic MCP testing framework and full-stack MCP App framework for ChatGPT Apps, Claude Connectors, and more.
What is Sunpeak MCP Framework?
Sunpeak MCP Framework is a Model Context Protocol (MCP) server that allows AI assistants like Claude, Cursor, and VS Code to server-agnostic mcp testing framework and full-stack mcp app framework for chatgpt apps, claude connectors, and more.
Server-agnostic MCP testing framework and full-stack MCP App framework for ChatGPT Apps, Claude Connectors, and more.
This server falls under the Developer Tools category on MCPgee, the world's largest MCP server directory with 33,000+ servers.
Features
- Server-agnostic MCP testing framework and full-stack MCP App
Use Cases
Maintainer
Works with
Installation
Manual Installation
npx sunpeakConfiguration
Configuration Details
claude_desktop_config.json
Performance
Response Metrics
Resource Usage
How to Set Up and Use Sunpeak MCP Framework
Sunpeak is a server-agnostic MCP testing framework and full-stack app framework for building cross-platform MCP Apps that run inside ChatGPT (as ChatGPT Apps) and Claude (as Claude Connectors). It replicates the ChatGPT and Claude runtimes locally so developers can write end-to-end and visual regression tests in CI without accounts or API credits, iterate with hot-module reloading, and run multi-model evals across GPT-4o, Claude Sonnet, and Gemini 2.0 Flash. Teams use Sunpeak to eliminate the manual refresh-and-click testing cycle that normally accompanies MCP App development.
Prerequisites
- Node.js 18 or higher (LTS recommended)
- npm or npx available on your PATH
- An MCP-compatible host for integration testing (Claude Desktop, Cursor, or a local MCP client)
- Optional: API keys for OpenAI, Anthropic, or Google if you want to run multi-model evals
Scaffold a new Sunpeak MCP App
Run the create command to generate a new project with the recommended directory structure, a dev server, and the Sunpeak inspector pre-configured.
npx sunpeak newExplore the project structure
Sunpeak auto-discovers tools, resources, and simulation fixtures from the filesystem. The key directories are src/tools/ for tool handlers, src/resources/ for UI components (React), and tests/simulations/ for mock data.
Start the development server
Launch the dev server with hot-module reloading. The Sunpeak inspector opens at localhost:3000 where you can toggle between ChatGPT and Claude runtimes, themes, and display modes.
npm run devScaffold tests for an existing MCP server
Point the test scaffolder at any running MCP server to generate E2E tests, visual regression tests, live tests, and multi-model eval cases.
npx sunpeak test init --server http://localhost:8000/mcpRun the full test suite
Execute all tests — Playwright-based E2E, visual regression, and model evals — without needing live ChatGPT or Claude accounts.
npx sunpeak testInspect any existing MCP server
Point the standalone inspector at any MCP server in any language to preview how its tools and resources render inside ChatGPT and Claude.
npx sunpeak inspect --server http://localhost:8000/mcpSunpeak MCP Framework Examples
Client configuration
Register a locally running Sunpeak MCP App as an MCP server in Claude Desktop for integration testing.
{
"mcpServers": {
"sunpeak-app": {
"command": "npx",
"args": ["sunpeak", "serve"]
}
}
}Prompts to try
Example Sunpeak test code and inspector usage patterns.
- "Run npx sunpeak test to execute the full test suite and show me which eval cases failed on GPT-4o-mini"
- "Use the Sunpeak inspector to show me how the show-albums tool renders in ChatGPT dark mode"
- "Scaffold tests for my MCP server at http://localhost:9000/mcp and then run just the eval cases"
- "Write a Sunpeak test that calls the search tool with query 'headphones' and asserts the result is not an error"Troubleshooting Sunpeak MCP Framework
Inspector shows a blank iframe for the ChatGPT runtime
Ensure your MCP server is running and reachable at the URL passed to --server. Check the browser console inside the inspector for CORS errors; add the inspector origin (http://localhost:3000) to your server's allowed origins.
Eval cases fail with 'model not found' errors
Multi-model evals require API keys for each provider. Set OPENAI_API_KEY, ANTHROPIC_API_KEY, or GOOGLE_GENERATIVE_AI_API_KEY in your .env file depending on which models you want to evaluate against.
npx sunpeak new hangs or fails to create the project
Ensure you are running Node.js 18+ (check with node --version). If the package download stalls, try clearing the npx cache with `npx clear-npx-cache` and retrying.
Frequently Asked Questions about Sunpeak MCP Framework
What is Sunpeak MCP Framework?
Sunpeak MCP Framework is a Model Context Protocol (MCP) server that server-agnostic mcp testing framework and full-stack mcp app framework for chatgpt apps, claude connectors, and more. It connects AI assistants to external tools and data sources through a standardized interface.
How do I install Sunpeak MCP Framework?
Follow the installation instructions on the Sunpeak MCP Framework GitHub repository. Clone the repo, install dependencies, and add the server config to your AI client.
Which AI clients work with Sunpeak MCP Framework?
Sunpeak MCP Framework works with all major MCP-compatible AI clients including Claude Desktop, Claude Code, Cursor, VS Code (GitHub Copilot), Windsurf, and Cline.
Is Sunpeak MCP Framework free to use?
Yes, Sunpeak MCP Framework is open source and available under the MIT license. You can use it freely in both personal and commercial projects.
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Set Up Sunpeak MCP Framework in Your Editor
Choose your AI client for step-by-step setup instructions.
Quick Config Preview
Add this to your claude_desktop_config.json or .cursor/mcp.json
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