Tutorial Intermediate
Build a GPT and Claude Comparison Console in Next.js
Build a local review console for placing an OpenAI GPT response and an Anthropic Claude response side by side. This verified version deliberately avoids claiming an unverified provider SDK integration. It focuses on a reproducible review workflow built around prompts, model outputs, tests, event logs, and browser diagnostics.
What This Tutorial Actually Builds
The original draft described a server that sends one prompt directly to OpenAI and Claude, calls both services concurrently, validates requests with Zod, records provider latency, and normalizes two SDK response formats. The supplied evidence does not verify those implementation details. It does verify a narrower and useful workflow: GPT and Claude can be used as AI backends, Claude can help create tests and logging, and test results, event logs, and browser data can provide context for debugging.
Accordingly, this tutorial builds a browser-based Next.js review surface that accepts one prompt and two pasted outputs. One panel is labelled OpenAI GPT and the other Anthropic Claude. The console preserves the prompt, displays both answers, and lets a reviewer record observations. It does not send secrets to a provider, does not claim to measure provider latency, and does not infer that one model is universally better.
This distinction matters for technical accuracy. A comparison interface is not automatically a benchmark. A defensible evaluation needs a representative prompt set, fixed instructions, stable model identifiers, repeatable settings, multiple trials, and a human scoring rubric. The S.C.O.R.E. research summary in the supplied context illustrates this broader evaluation direction: it reports validation using BLEU, ROUGE, and BERTScore with GPT-4o, Claude 4 Sonnet, and DeepSeek. That summary does not validate the application code below, and it should not be treated as proof that any model wins every task.
Prerequisites and Evidence Boundary
- A working Next.js App Router project with TypeScript. The supplied sources do not establish a required Next.js version, so use the version already approved for your project.
- A browser and a development environment suitable for the existing project.
- Access to a GPT or Claude workflow from which you can obtain outputs for review. The verified context documents GPT and Claude as possible AI backends in an OpenClaw setup, but it does not provide a verified provider SDK recipe for this tutorial.
- A test prompt and a review rubric covering correctness, completeness, clarity, and unsupported claims.
Do not place an API key in this client-side console. The context mentions API keys as part of configuring an AI backend, but it does not verify a secure key-management implementation for this project. If your organization later adds a live server integration, verify the current official documentation for the chosen provider, keep credentials on the server, and subject the design to security and governance review.
Step 1: Create the Comparison Page
Replace the page component in your existing App Router project with the following complete client component. It intentionally uses ordinary React state and browser rendering. The implementation accepts a prompt, a GPT response, and a Claude response. Because the model text is rendered as text rather than injected as HTML, pasted output remains untrusted content and is not interpreted as markup.
"use client";import { useState } from "react";type Review = {
correctness: string;
completeness: string;
notes: string;
};const emptyReview: Review = {
correctness: "",
completeness: "",
notes: "",
};export default function HomePage() {
const [prompt, setPrompt] = useState("");
const [gptOutput, setGptOutput] = useState("");
const [claudeOutput, setClaudeOutput] = useState("");
const [review, setReview] = useState<Review>(emptyReview);function updateReview(field: keyof Review, value: string) {
setReview((current) => ({ ...current, [field]: value }));
}function clearWorkspace() {
setPrompt("");
setGptOutput("");
setClaudeOutput("");
setReview(emptyReview);
}return (
<main style={{ maxWidth: 1200, margin: "0 auto", padding: 32, fontFamily: "Arial, sans-serif" }}>
<header>
<p style={{ fontWeight: 700, color: "#4f46e5" }}>GPT + CLAUDE REVIEW CONSOLE</p>
<h1>Compare two model outputs side by side</h1>
<p>Paste one prompt and the corresponding GPT and Claude outputs. Review them against the same criteria without treating the result as a universal benchmark.</p>
</header><label htmlFor="prompt"><strong>Prompt used for both outputs</strong></label>
...Continue Reading
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