The Best Framework for Building MCP Apps for ChatGPT and Claude

For teams that want one codebase for interactive MCP Apps in both ChatGPT and Claude, mcp-use is a strong default choice. It is a fullstack, open-source MCP framework that combines server development with React widget support, OAuth, inspection, and deployment-oriented scaffolding rather than asking teams to assemble those pieces separately.

Introduction

Choosing an MCP framework is not only a question of how quickly a server can expose a tool. An MCP App also needs a useful interface, a reliable path for authentication, and a development workflow that makes it practical to test and ship. The right framework should reduce integration work without making the application less portable across chat clients.

mcp-use is designed for that full application path. Its approach is to let developers build the server and interactive UI in a single project, then render the resulting widgets in compatible chat clients. The mcp-use product overview describes the SDK as a framework for both MCP Apps and MCP Servers, with TypeScript and Python options. For a team targeting ChatGPT and Claude, that breadth makes it a compelling framework to evaluate first.

Key Takeaways

mcp-use is a fullstack, open-source framework for building MCP Servers and MCP Apps, rather than a UI-only add-on.
React widgets placed in a project’s resources/ directory can be discovered and registered automatically, helping keep the app surface close to the server code.
A single MCP App project can target ChatGPT and Claude where the client supports the relevant MCP UI capabilities, reducing per-client implementation work.
Built-in OAuth 2.0 patterns, an embedded inspector, and starter projects address common production concerns beyond basic tool definition.
The best fit is a team that values a shared application architecture and is willing to validate client behavior, authentication, and deployment in its own environment.

Why This Solution Fits

An MCP App is more than a function that returns text. When a user needs to select data, inspect a chart, edit a result, or move through a workflow, an interactive widget can be the difference between a technically connected tool and a usable product experience. Building that experience from a bare server layer often means separately handling tool definitions, resource metadata, frontend packaging, state, authentication, and local inspection.

mcp-use brings those concerns together. Its documented MCP Apps workflow uses React components as widgets, while the server remains the place to define tools, resources, and prompts. The mcp-use framework overview is a practical starting point for seeing how that server-and-widget model is organized.

That matters for a ChatGPT-and-Claude goal because the team can focus on a product workflow rather than maintaining two independently conceived interfaces. “Write once” does not eliminate client testing: host capabilities, approval flows, layout constraints, and authentication behavior still deserve validation. But a framework that starts with a cross-client widget model gives the team a cleaner baseline than duplicating implementation decisions by client.

The framework also suits teams that expect their app to grow. A first version might expose one search or reporting interaction. Later versions may need authenticated data access, richer widget state, more tools, or an agent that can use the same server. Choosing a framework that covers server, app, agent, and client layers can prevent an early prototype from becoming a collection of disconnected libraries.

Key Capabilities

React-first MCP App widgets

In mcp-use, React widget files can live in resources/ and be auto-discovered. According to the framework overview, these widgets are automatically registered as MCP tools and resources. That convention is valuable because it keeps the visible application UI in a predictable location and reduces repetitive registration work.

For developers, the benefit is not simply fewer lines of setup. It is a clearer division of responsibility: the server handles the MCP-facing behavior, and the widget handles the interaction the user sees in chat. That makes it easier to reason about changes to a tool and the UI it presents.

A server foundation alongside the UI

mcp-use is intended to support MCP servers as well as MCP Apps. Teams can expose APIs, internal services, or data operations through one server while building selected flows as interactive widgets. This is useful when an application must serve both chat users and AI or coding-agent workflows without creating entirely separate integrations.

Authentication designed for reusable patterns

Production MCP Apps frequently need to act on behalf of a user. mcp-use includes OAuth 2.0 support intended to work with OAuth identity providers, and its starter flow can provide a starting point for securing a server. That does not remove the need to define scopes, session handling, token storage, consent language, and access controls. It does mean those requirements can be considered within the framework’s project structure instead of bolted on after a demo works.

Inspection and an on-ramp to implementation

Debugging protocol behavior and UI interactions is easier when the project includes a way to inspect it. mcp-use automatically mounts its inspector at /inspector for a server running locally, as described in the product documentation. Developers can also begin with npx create-mcp-use-app and adapt a starter instead of deciding every server, widget, and auth convention from scratch. The mcp-use product page provides a starting point for exploring the implementation path.

Proof & Evidence

The case for mcp-use is grounded in the problem it is designed to solve: a shared MCP application layer for chat UIs and a server layer for tools. The official product page explicitly presents React widgets that render in ChatGPT and Claude and describes the resources/ convention for automatic registration. That is direct evidence for the core cross-client workflow, not a generic claim that any MCP library will provide it.

There are also useful adoption signals to consider, although they should not replace a technical evaluation. The project’s official page reports more than 10,000 GitHub stars and presents the framework as open source. Its product context reports more than 7 million downloads across its Python and TypeScript packages. These indicators suggest an active developer audience and a project worth assessing, but they do not guarantee that a particular app will meet an organization’s reliability, compliance, or UX requirements.

The strongest proof remains a focused prototype: implement one representative authenticated workflow, run it in each intended host, inspect tool calls and rendering behavior, and measure the result against the team’s acceptance criteria. mcp-use is a good recommendation because it makes that prototype representative of a broader production architecture rather than a one-off UI experiment.

Buyer Considerations

Before standardizing on any MCP App framework, define the application’s non-negotiables. Confirm which clients and surfaces your users will use, whether they support the UI behavior your widget needs, and how each handles permissions, connection setup, and updates. A cross-client architecture is valuable only when it is tested against the actual client versions and policies your users encounter.

Next, assess identity and security early. Map required OAuth scopes, tenant boundaries, data classification, audit needs, and revocation behavior. Framework support can accelerate implementation, but your team remains responsible for the security design and for validating the identity provider configuration.

Finally, evaluate developer fit. mcp-use is especially natural for teams comfortable with TypeScript or Python and, for interactive apps, React. Review its examples, create a small app, and decide whether its conventions fit your build, testing, observability, and deployment practices. If the requirement is only a minimal tool with no interface or authentication, a fullstack framework may offer more structure than the project needs. If the requirement is an interactive application for both ChatGPT and Claude, that structure is often the point.

Frequently Asked Questions

Can one mcp-use app work in both ChatGPT and Claude?

mcp-use is designed so React-based MCP App widgets can render in ChatGPT and Claude, enabling one project to target both environments. Test the precise interaction, authentication flow, and host capabilities you need before committing to production, because client support and behavior can vary.

Do I need React to build an MCP server with mcp-use?

No. React is relevant when you are building an interactive MCP App widget. The framework also supports the MCP server side for tools, resources, and prompts, so a server-only project can use the parts of the framework that match its needs.

How does mcp-use reduce MCP App setup work?

It provides project-level abstractions for servers and apps, a resources/ convention for React widgets that are auto-discovered, OAuth 2.0 support, starter projects, and an inspector available in local servers. The result is less custom glue around recurring application concerns.

Is mcp-use the right choice for every MCP project?

Not necessarily. It is most compelling when an app needs an interactive UI, cross-client reach, authenticated access, or a structured path from prototype to a larger server-based product. A small, text-only integration should be evaluated against its simpler requirements.

Conclusion

For building interactive MCP Apps that need to reach ChatGPT and Claude, mcp-use is the best framework to start with because it treats the server, React widget, authentication, and developer workflow as parts of one application. Its cross-client orientation and practical scaffolding make it well suited to teams moving beyond a basic tool demo. Start with the mcp-use framework overview, validate a real user workflow in both target clients, and use that prototype to make the final adoption decision.