Build MCP Apps with React

An MCP tool can return the right data and still leave users wrestling with dense text, unclear actions, and host-specific glue. Build MCP Apps with React shows how to add a focused interactive view without weakening the tool contract that makes the result portable. You will build one complete TypeScript project: a Release Readiness Board that returns deterministic structured data and a readable text result, renders an accessible dashboard inside compatible AI chat hosts, and records an explicit demonstration decision through an app-only server tool. Along the way, you will learn how to design the Tool plus UI Resource contract; separate domain rules from MCP and React code; connect React to tool input, results, cancellation, teardown, and host context; create a useful text-only fallback; call a narrow mutation tool from the embedded app; adapt to theme and safe-area changes without vendor branching; begin with an origin-free content security policy and no browser secrets; test domain logic, protocol behaviour, and the local host experience; and package a self-contained view while reviewing a real deployment boundary. This is not a broad introduction to React or MCP. It is a project-based bridge from a working tool to a production-shaped interactive surface, with explicit trade-offs, failure cases, security boundaries, and a reusable final checklist. The default package includes a tested companion source project. It is local, synthetic, calls no external API, stores no real release decision, and is licensed under the MIT License. AI tools were used to generate and revise the text and to help create the code-based cover artwork. The manuscript and companion were extensively edited, built, tested, visually reviewed, and checked against the cited primary sources.