15分で初めてのAIエージェントを構築する方法

mkdir my-first-agent && cd my-first-agent
npm init -y
npm install @anthropic-ai/sdk
npm install -D tsx typescript

{
  "scripts": {
    "agent": "tsx agent.ts"
  }
}

import Anthropic from "@anthropic-ai/sdk";

const client = new Anthropic({
  apiKey: process.env.ANTHROPIC_API_KEY,
});

const SYSTEM_PROMPT = `You are a precise content summarizer. When given any block of text, return a structured summary in this exact format:

**One-line summary:** <the core point in one sentence>

**Key points:**
- <point 1>
- <point 2>
- <point 3 if applicable>

**Action item (if any):** <one concrete next step, or "None">

Be specific. No filler. Under 150 words total.`;

async function summarize(text: string): Promise<string> {
  const message = await client.messages.create({
    model: "claude-haiku-4-5",
    max_tokens: 512,
    system: SYSTEM_PROMPT,
    messages: [{ role: "user", content: text }],
  });

  const block = message.content[0];
  if (block.type !== "text") throw new Error("Unexpected response type");
  return block.text;
}

const sample = `
  Hey team — following up on the Q2 review meeting.
  We agreed to push the launch to July 15th instead of June 30th
  due to the payment integration delay. Marketing needs the new
  landing page copy by June 20th or we can't start the email campaign.
  Budget for the launch campaign is confirmed at $8,000.
  Please confirm receipt.
`;

const result = await summarize(sample);
console.log(result);

ANTHROPIC_API_KEY=sk-ant-... npm run agent

**One-line summary:** Launch pushed to July 15th due to payment delay; landing page copy needed by June 20th to unblock email campaign.

**Key points:**
- Launch date moved from June 30th to July 15th
- Landing page copy deadline: June 20th (blocks email campaign)
- Campaign budget confirmed at $8,000

**Action item (if any):** Confirm receipt and deliver landing page copy by June 20th.

Classify this customer review as POSITIVE, NEGATIVE, or MIXED.
Then extract the main complaint or praise in one sentence.
Format: SENTIMENT: <label>
RESUME: <one sentence>

Extract all action items from this meeting transcript.
Format each as: [OWNER if mentioned] [ACTION] by [DEADLINE if mentioned]
If owner or deadline is not stated, leave those fields blank.
Return a numbered list. No preamble.

Rewrite this text in a direct, confident, first-person tone for LinkedIn.
Remove hedging language ("I think", "maybe", "sort of").
Keep it under 200 words. Return only the rewritten text, no commentary.

npm install -g wrangler
wrangler init my-agent-worker --template worker-typescript
cd my-agent-worker
npm install @anthropic-ai/sdk

wrangler secret put ANTHROPIC_API_KEY

import Anthropic from "@anthropic-ai/sdk";

export default {
  async fetch(request: Request, env: Env): Promise<Response> {
    const { text } = await request.json<{ text: string }>();

    const client = new Anthropic({ apiKey: env.ANTHROPIC_API_KEY });
    const message = await client.messages.create({
      model: "claude-haiku-4-5",
      max_tokens: 512,
      system: YOUR_SYSTEM_PROMPT,
      messages: [{ role: "user", content: text }],
    });

    const block = message.content[0];
    if (block.type !== "text") return Response.json({ error: "Bad response" }, { status: 500 });
    return Response.json({ summary: block.text });
  },
};

wrangler deploy