在 Cloudflare 上部署 Agent

/agents/support-agent/user_123
        └─ 固定路由到 user_123 这个实例

npm create cloudflare@latest -- --template=cloudflare/agents-starter
cd my-agent
npm install
npm run dev

npx wrangler deploy

import { Agent, routeAgentRequest } from "agents";

type State = {
  messages: Array<{ role: "user" | "assistant"; content: string }>;
};

export class SupportAgent extends Agent<Env, State> {
  initialState: State = { messages: [] };

  async onRequest(request: Request): Promise<Response> {
    const { message } = await request.json<{ message: string }>();

    const history = [...this.state.messages, { role: "user" as const, content: message }];
    const result = await this.env.AI.run("@cf/meta/llama-3.1-8b-instruct", {
      messages: history,
    });

    const reply = (result as { response?: string }).response ?? "";
    this.setState({
      messages: [...history, { role: "assistant", content: reply }],
    });

    return Response.json({ reply });
  }
}

export default {
  async fetch(request: Request, env: Env) {
    return (
      (await routeAgentRequest(request, env)) ??
      new Response("Not found", { status: 404 })
    );
  },
};

{
  "name": "support-agent",
  "main": "src/index.ts",
  "compatibility_date": "2026-01-01",
  "durable_objects": {
    "bindings": [{ "name": "SupportAgent", "class_name": "SupportAgent" }]
  },
  "migrations": [{ "tag": "v1", "new_sqlite_classes": ["SupportAgent"] }],
  "ai": { "binding": "AI" }
}

// 读取
const count = this.state.count ?? 0;

// 写入（会持久化）
this.setState({ ...this.state, count: count + 1 });

// SQLite，适合结构化数据
this.sql`CREATE TABLE IF NOT EXISTS events (id TEXT PRIMARY KEY, payload TEXT)`;
this.sql`INSERT INTO events (id, payload) VALUES (${id}, ${JSON.stringify(payload)})`;

import { WorkflowEntrypoint, WorkflowStep } from "cloudflare:workers";

export class ResearchWorkflow extends WorkflowEntrypoint<Env, { topic: string }> {
  async run(event: WorkflowEvent<{ topic: string }>, step: WorkflowStep) {
    const plan = await step.do("plan", async () => {
      return await makePlan(event.payload.topic);
    });

    const docs = await step.do(
      "retrieve",
      { retries: { limit: 3, delay: "10 seconds", backoff: "exponential" } },
      async () => await retrieve(plan.queries)
    );

    const report = await step.do("write", async () => {
      return await writeReport(plan, docs);
    });

    await step.do("save", async () => {
      await this.env.BUCKET.put(`reports/${event.instanceId}.md`, report);
    });

    return { report };
  }
}

// 写入
const embedding = await this.env.AI.run("@cf/baai/bge-m3", { text: chunks });
await this.env.VECTORIZE.upsert(
  chunks.map((text, i) => ({
    id: `${docId}-${i}`,
    values: embedding.data[i],
    metadata: { docId, title, page: i },
  }))
);

// 查询
const q = await this.env.AI.run("@cf/baai/bge-m3", { text: [question] });
const matches = await this.env.VECTORIZE.query(q.data[0], {
  topK: 8,
  returnMetadata: "all",
});