For content you produce every week, use Claude Sonnet 5.

Claude API, TypeScript

Start from this.

Edit the parts in capitals, then run it.

import Anthropic from "@anthropic-ai/sdk";
import { readFileSync } from "node:fs";

const client = new Anthropic();
const brandGuide = readFileSync("BRAND_GUIDE.md", "utf8");

export async function draftEmail(lead: { name: string; company: string; trigger: string }) {
  const res = await client.messages.create({
    model: "claude-sonnet-5",
    max_tokens: 4000,
    output_config: {
      effort: "low",
      format: {
        type: "json_schema",
        schema: {
          type: "object",
          properties: { subject: { type: "string" }, body: { type: "string" } },
          required: ["subject", "body"],
          additionalProperties: false,
        },
      },
    },
    system: [{ type: "text", text: brandGuide, cache_control: { type: "ephemeral" } }],
    messages: [{ role: "user", content: `Write a first-touch email to ${lead.name} at ${lead.company}. Reason to write: ${lead.trigger}.` }],
  });
  const text = res.content.find((b) => b.type === "text");
  return JSON.parse(text && text.type === "text" ? text.text : "{}");
}