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Sharing our learnings from building MCPJam and the MCP community.

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Latest

Effective MCP, Part 1: The User Value Problem

In MCP, your integration can execute perfectly while failing the user completely in practice, yet you have almost no visibility into the actual outcome.

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More from the blog

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MCPJam Inspector Web App

MCPJam web app provides easy access to testing your MCP app, ChatGPT app, and MCP server directly in the browser, no downloads required.

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Share and mock MCP app views

Save, share, and mock MCP app views with MCPJam. Track your app's UI progress, collaborate with teammates, and mock data to see your UI in different states.

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5 Tips for Building MCP Apps That Work

Practical lessons for building MCP Apps that feel native across multiple hosts. Learn how to adapt to host environments, control data flow, handle loading states, and more.

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Test Skills + MCP in MCPJam

Learn how to pair Skills with MCP servers in MCPJam. Test your skills and MCP server together in the LLM playground.

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Projects are now in MCPJam

Projects are now available in MCPJam, a new way to organize your work in the inspector. Use projects to group your servers and share them with your team.

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MCPJam 2025 Rewind - Our stories and learnings

2025 has been a great year for the MCP community and us at MCPJam. We wanted to share our story, celebrate our accomplishments this year, and our learnings.

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Submit ChatGPT apps - Passing Test Cases

OpenAI recently announced they're opening the ChatGPT app store for app submissions. Learn how to pass test cases with MCPJam's evals platform.

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Monetizing your ChatGPT app, and the Agentic Commerce Protocol

Learn how to implement instant checkout in your ChatGPT app using OpenAI's Agentic Commerce Protocol (ACP) and test it locally with MCPJam.

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How to work with MCP Tasks

A technical dive into how Tasks work at the protocol level in the November 2025 MCP spec, and how you can implement this feature in your MCP server.

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3 MCP features you probably didn't know about

Explore three underrated MCP features: progress notifications, log levels, and icons. Learn how to implement them in your MCP servers.

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Introducing ChatGPT Apps and MCP Apps Builder

Introducing a new way to build ChatGPT Apps and MCP Apps locally.

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Deploy a MCP App (UI) on Cloudflare Workers

Learn how to deploy MCP Apps with rich user interfaces on Cloudflare Workers. Complete guide with template, configuration, and deployment instructions.

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Build your first MCP App (UI)

Teams from MCP-UI, Anthropic, and OpenAI collaborated on a new standard to bring interactive UI to MCP clients. Learn how to build your first MCP App with real code examples.

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MCP Apps (UI) support preview

MCPJam built the first working client prototype that supports MCP Apps. Learn about the collaboration between MCP-UI, Anthropic, and OpenAI to create the new MCP Apps standard.

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Develop ChatGPT apps with full observability (ngrok)

MCPJam's ngrok tunneling feature enables you to observe all JSON-RPC messages sent between ChatGPT and your app via the ngrok tunnel.

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MCP server instructions - give LLMs more context on your MCP server

Learn how to write effective MCP server instructions to improve tool ergonomics and help LLMs better understand how to use your MCP server.

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Evaluating MCP servers - a quick guide

Learn how to measure and improve your MCP server's tool ergonomics using evals. Track accuracy, precision, and performance across multiple LLMs.

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Track your MCP server's token use

Learn how to optimize your MCP server's token usage to prevent performance degradation, context loss, and hallucinations. Track token use in MCPJam Playground.

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Open AI Apps SDK - Server Everything

A comprehensive reference implementation demonstrating all capabilities of the OpenAI Apps SDK.

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MCPJam OAuth Debugger: Test every step of the MCP auth flow

Test every step of the MCP auth flow with MCPJam's OAuth debugger. Pinpoint issues in your auth implementation.

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The MCP authentication checklist (November 2025 spec)

Step-by-step MCP OAuth guide. Covers the latest November 2025 spec with Client ID Metadata Documents (CIMD).

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New MCP playground - Playground V2

MCPJam's new Playground V2 brings full support for MCP-UI and OpenAI Apps SDK, free frontier models, and advanced debugging tools for MCP server developers.

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Writing MCP server unit tests

Learn how to write comprehensive unit tests for MCP servers using the MCPJam SDK and Jest. Test tools, prompts, and resources to ensure your MCP server is production-ready.

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We added frontier models to our MCP playground for free

Access GPT-5, Claude 4.5, Gemini 2.5, and more frontier models inside MCPJam's LLM playground without your own API keys.

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MCPClientManager - A Better Way to Build MCP Clients

Launching MCPClientManager, a powerful class to build real world MCP clients. Learn how to build fully capable clients.

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Progressive disclosure might replace MCP (Claude Agent Skills)

We cover the tradeoffs of progressive disclosure and MCP, and the future of MCP with Claude Agent Skills.

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Debug MCP servers at the JSON-RPC level

Learn how JSON-RPC powers MCP server communication, understand message types, and debug your MCP server effectively at the protocol level.

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A look at OpenAI's Apps SDK under the hood

Dive into the architecture of OpenAI's Apps SDK, how it uses MCP servers and widgets, and the window.openai API.

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Building with OpenAI Apps SDK

We built Apps SDK support in MCPJam's open source inspector to help you test your Apps SDK server, give you a head start.