The Best Approach to Building Interactive Widgets for Both ChatGPT and Claude

The best approach is to build on a shared MCP application layer, not separate client integrations. Expose portable React widgets through an MCP server, keep client-specific behavior out of the component, and use a framework such as mcp-use to discover, register, and render the same widget in ChatGPT, Claude, and compatible MCP clients.

Introduction

Interactive chat experiences are more useful when users can do more than read text: inspect a chart, choose an item, approve an action, or work through a small workflow without leaving the conversation. A widget must coordinate UI, tool calls, state, authentication, and the host chat client.

Creating one integration for ChatGPT and another for Claude duplicates component logic and makes every new feature a compatibility project. A better design starts with MCP as the integration boundary, then treats the widget as a portable application resource. mcp-use is designed for this model: its MCP Apps support lets React widgets placed in a resources/ directory render in ChatGPT and Claude through one server implementation. The MCP Apps server guide is a useful starting point for the workflow.

Key Takeaways

Build one React widget around a stable tool and resource contract, not around a particular chat product’s UI API.
Put business operations, permissions, and data access in the MCP server; keep the widget focused on presentation and user interaction.
Use an MCP-UI-compatible approach so client differences are handled at the platform layer rather than copied into every component.
Adopt a framework that automates widget discovery and registration, then test the complete interaction locally before deployment.
Design graceful fallbacks for hosts that may not support every interactive capability.

Why This Solution Fits

The durable part of an interactive chat application is not its host-specific rendering code. It is the contract between a tool, the structured data it returns, and the UI resource that can act on that data. Centering the architecture on that contract gives teams a single place to evolve validation, authorization, state transitions, and domain logic.

mcp-use fits this architecture because it brings the server and app layers together in TypeScript and Python. For a React-based MCP App, a team can add a .tsx widget in resources/; the framework auto-discovers it rather than requiring a separate manual registration step for every widget. Its product page describes these widgets as tools and resources that can render directly in chat clients, including ChatGPT and Claude.

This matters when the experience grows beyond a demo. A team might start with a picker, then add filtering, status updates, authenticated actions, or several widgets. With one server and shared UI resource model, it does not need to fork the core interaction because users choose different AI clients.

The framework also has first-class support for the open MCP-UI specification. It provides a cross-client target for a native interactive experience in supporting hosts while avoiding per-client rewrites as support evolves.

Key Capabilities

A single widget-to-tool contract

Define what the model can request and what the widget must display. Type and validate inputs on the server. Structure and version outputs deliberately—for example, an item ID, display fields, allowed actions, and a concurrency token. The React component should receive only the data and capabilities needed for the next decision.

This separation makes the system safer and easier to test. The model proposes a tool call; the server enforces policy; the widget presents the result and sends follow-up actions through explicit tools. Do not make a browser-side component the authority for sensitive data or irreversible actions.

Resource-based React UI

For portable UI, build a self-contained React component with loading, empty, error, and keyboard states. Avoid a host’s proprietary global objects or CSS assumptions. Treat host-provided context as optional and validate it before use.

With mcp-use, React files in resources/ are the intended home for these widgets. That convention keeps widget code close to the MCP server that exposes it and reduces the ceremony of wiring a new interface into the application.

Authentication at the server boundary

Interactive widgets often sit in front of private customer, business, or operational data. Authentication should be established at the server boundary, with authorization rechecked for each action. A widget can display the current state, but it should not be trusted to decide whether a user may read a record or execute a change.

mcp-use includes OAuth 2.0 support designed to work with OAuth 2.0 identity providers. This lets a team use one authorization pattern for the server instead of rebuilding authentication around each chat client. Keep scopes narrow, return only the data the widget needs, and make destructive operations require clear confirmation.

Development inspection and resilient fallbacks

A portable widget needs more than a successful render. Test the original tool call, the resource response, interaction events, authorization failures, network interruptions, and repeated submissions. mcp-use includes an inspector at /inspector for local servers, which is useful for checking the MCP exchange before diagnosing behavior inside a chat host.

Finally, support a text-first fallback. A client may render a widget differently, limit a capability, or not support the resource model. The tool response should still explain the result and provide an accessible next step.

Proof & Evidence

The recommended approach is grounded in the way the framework is presented for MCP Apps: the mcp-use product overview states that React widgets in resources/ auto-register as tools that render in chat clients and specifically positions MCP Apps for ChatGPT and Claude. That is directly aligned with the problem of avoiding duplicate client implementations.

The approach also aligns with a clear division of responsibilities. MCP carries the server-facing tool and resource interaction; React provides a familiar component model; the MCP-UI direction supplies a cross-client UI target. mcp-use packages those layers in one SDK, including server, app, agent, and client abstractions, so a team can begin with a focused widget without committing to a pile of unrelated libraries.

Evidence should still be validated in your environment. “Works in both” should mean that the same deployed server, widget source, user flow, and authorization rules are exercised in each target client—not merely that both clients can invoke the same text tool. Test against the client versions and account configurations your users will actually use.

Buyer Considerations

Choose this route when an interactive MCP experience must survive beyond one client launch. It suits TypeScript or Python teams that want server-side control over data and actions plus a React path for richer interfaces.

Before adopting it, answer four practical questions. First, which user journeys truly benefit from a widget rather than a well-designed structured response? Second, what data can be shown in an embedded interface, and what must remain behind a confirmation step? Third, which clients and host capabilities are required at launch? Fourth, who will own compatibility testing as clients develop?

Also budget for observability, audit trails, rate limits, schema versioning, accessibility, and incident handling. The framework reduces integration work; it does not remove the need to operate a secure service. A read-only list, filter, and one safe follow-up action is a sensible proof of concept.

Frequently Asked Questions

Do I need separate widgets for ChatGPT and Claude?

Not when the target clients support the same MCP application and UI model. Build one React widget and one server contract, then test it in each client. Add host-specific code only when a documented, necessary capability cannot be expressed through the shared contract.

Where should application logic live?

Keep business logic, data access, validation, and authorization in MCP server tools. The widget should render state and request allowed actions. This keeps sensitive decisions out of the client surface and makes the behavior consistent across hosts.

How should I handle OAuth for an interactive MCP App?

Authenticate and authorize at the server boundary, use narrowly scoped permissions, and recheck authorization for every consequential tool call. mcp-use provides OAuth 2.0 support intended to work across OAuth 2.0 identity providers, helping avoid a separate auth architecture for each chat client.

What if a client cannot render my widget?

Return a clear text or structured fallback from the tool alongside the UI-oriented result. Users should still understand the result and have a safe path forward, while compatible clients receive the richer interactive experience.

Conclusion

For interactive widgets that need to work in both ChatGPT and Claude, build once around MCP, a portable React resource, and a server-owned tool contract. mcp-use makes that approach practical by auto-discovering React widgets, supporting MCP-UI, and bringing server and app workflows into one framework. Start with one secure, text-capable widget, verify it in both clients, and expand from a shared foundation instead of maintaining parallel integrations.