Calling a language model API

struct Insights: Decodable {
    let title: String
    let mood: String       // one word, e.g. "reflective"
    let reflection: String // a follow-up question
}

import Foundation

enum InsightsService {
    static func generate(for entryText: String, apiBase: URL) async throws -> Insights {
        // We call OUR backend (apiBase), which holds the secret key. See next lesson.
        var request = URLRequest(url: apiBase.appendingPathComponent("reflect"))
        request.httpMethod = "POST"
        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
        request.httpBody = try JSONEncoder().encode(["entry": entryText])

        let (data, response) = try await URLSession.shared.data(for: request)
        guard let http = response as? HTTPURLResponse, http.statusCode == 200 else {
            throw URLError(.badServerResponse)
        }
        return try JSONDecoder().decode(Insights.self, from: data)
    }
}

import Anthropic from "@anthropic-ai/sdk";
const anthropic = new Anthropic(); // reads ANTHROPIC_API_KEY from env

export default async function handler(req, res) {
  const { entry } = req.body;

  const message = await anthropic.messages.create({
    model: "claude-opus-4-8",
    max_tokens: 300,
    system:
      "You analyze a journal entry. Reply with ONLY minified JSON of the form " +
      '{"title": string, "mood": one word, "reflection": a short question}. No prose.',
    messages: [{ role: "user", content: entry }],
  });

  // Claude returns text; it's our JSON string.
  res.status(200).json(JSON.parse(message.content[0].text));
}