Claude Message Batches API in TypeScript (50% Off)

Turn yesterday's support tickets into batch requests, one per ticket.

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

const client = new Anthropic();

type Ticket = { id: number; subject: string; body: string };

const SYSTEM = `Classify the support ticket. Reply with JSON only:
{"category": "billing" | "bug" | "how-to" | "feature", "urgent": boolean}`;

function toRequests(tickets: Ticket[]) {
  return tickets.map((t) => ({
    custom_id: `ticket-${t.id}`, // must match ^[a-zA-Z0-9_-]{1,64}$
    params: {
      model: "claude-haiku-5-5",
      max_tokens: 100,
      system: SYSTEM,
      messages: [{ role: "user" as const, content: `${t.subject}\n\n${t.body}` }],
    },
  }));
}

Submit the batch, then poll until processing_status is "ended".

export async function submit(tickets: Ticket[]) {
  const batch = await client.messages.batches.create({ requests: toRequests(tickets) });
  return batch.id; // persist this
}

export async function waitForBatch(batchId: string, everyMs = 60_000) {
  for (;;) {
    const batch = await client.messages.batches.retrieve(batchId);
    const c = batch.request_counts;
    console.log(`${batch.processing_status}: ${c.succeeded} ok, ${c.errored} errored, ${c.processing} pending`);
    if (batch.processing_status === "ended") return batch;
    await new Promise((r) => setTimeout(r, everyMs));
  }
}

Stream results, save successes, and sort failures into retry-now and fix-first.

export async function collect(batchId: string) {
  const retry: string[] = [];
  const invalid: string[] = [];

  for await (const item of await client.messages.batches.results(batchId)) {
    const ticketId = Number(item.custom_id.replace("ticket-", ""));

    switch (item.result.type) {
      case "succeeded": {
        const block = item.result.message.content[0];
        const text = block.type === "text" ? block.text : "";
        await saveClassification(ticketId, JSON.parse(text)); // validate in real code
        break;
      }
      case "errored":
        // invalid_request_error means the request itself is wrong: fix before resending
        (item.result.error.type === "invalid_request_error" ? invalid : retry).push(item.custom_id);
        break;
      case "expired":
      case "canceled":
        retry.push(item.custom_id); // never sent to the model, not billed
        break;
    }
  }
  return { retry, invalid };
}