Claude API のレスポンスを Cloudflare R2 にアーカイブする実装メモ — 監査・再現性・障害分析の3軸設計

// 何もしていない素朴な実装（archive なし）
export default {
  async fetch(request: Request, env: Env, ctx: ExecutionContext) {
    const body = await request.json<ChatRequest>();
    const anthropic = new Anthropic({ apiKey: env.ANTHROPIC_API_KEY });
 
    const response = await anthropic.messages.create({
      model: "claude-sonnet-4-6",
      max_tokens: 4096,
      messages: body.messages,
    });
 
    return Response.json(response);
  },
} satisfies ExportedHandler<Env>;

// archive を組み込んだ実装
import Anthropic from "@anthropic-ai/sdk";
 
interface Env {
  ANTHROPIC_API_KEY: string;
  ARCHIVE_BUCKET: R2Bucket;
  ARCHIVE_META: D1Database;
}
 
export default {
  async fetch(request: Request, env: Env, ctx: ExecutionContext) {
    const body = await request.json<ChatRequest>();
    const anthropic = new Anthropic({ apiKey: env.ANTHROPIC_API_KEY });
 
    const response = await anthropic.messages.create({
      model: "claude-sonnet-4-6",
      max_tokens: 4096,
      messages: body.messages,
      metadata: { user_id: body.user_id },
    });
 
    // 先にレスポンスを返してしまう
    const httpResponse = Response.json(response);
 
    // 副作用は裏で走らせる
    ctx.waitUntil(
      archiveResponse({
        env,
        request: body,
        response,
        userId: body.user_id,
      }),
    );
 
    return httpResponse;
  },
} satisfies ExportedHandler<Env>;
 
async function archiveResponse(args: {
  env: Env;
  request: ChatRequest;
  response: Anthropic.Message;
  userId: string;
}) {
  const { env, request, response, userId } = args;
  const requestId = response.id; // msg_01HXYZ...
  const now = new Date();
  const yyyy = now.getUTCFullYear();
  const mm = String(now.getUTCMonth() + 1).padStart(2, "0");
  const dd = String(now.getUTCDate()).padStart(2, "0");
  const hh = String(now.getUTCHours()).padStart(2, "0");
  const key = `claude-archive/${yyyy}/${mm}/${dd}/${hh}/${requestId}.json`;
 
  const record = {
    schema_version: "v1",
    request_id: requestId,
    ts: now.toISOString(),
    model: response.model,
    request: maskPII(request),
    response,
    client: { site: "claudelab", version: env.BUILD_VERSION ?? "dev" },
  };
 
  await env.ARCHIVE_BUCKET.put(key, JSON.stringify(record), {
    httpMetadata: { contentType: "application/json" },
    customMetadata: {
      userId,
      model: response.model,
      stopReason: response.stop_reason ?? "unknown",
    },
  });
 
  // メタデータインデックスを D1 に書く
  await env.ARCHIVE_META.prepare(
    `INSERT INTO archive_index
       (request_id, user_id, ts, model, stop_reason, input_tokens, output_tokens, r2_key)
     VALUES (?, ?, ?, ?, ?, ?, ?, ?)`,
  )
    .bind(
      requestId,
      userId,
      now.toISOString(),
      response.model,
      response.stop_reason,
      response.usage.input_tokens,
      response.usage.output_tokens,
      key,
    )
    .run();
}

function maskPII(request: ChatRequest): MaskedRequest {
  return {
    ...request,
    messages: request.messages.map((m) => ({
      ...m,
      content: typeof m.content === "string"
        ? maskText(m.content)
        : m.content,
    })),
  };
}
 
function maskText(text: string): string {
  return text
    // メールアドレス
    .replace(/[\w.+-]+@[\w.-]+\.[A-Za-z]{2,}/g, "<email>")
    // 電話番号（日本国内・国際フォーマット）
    .replace(/\+?\d[\d\-\s]{8,}/g, "<phone>")
    // 16 桁のカード番号らしき並び
    .replace(/\b(?:\d[ -]?){13,16}\b/g, "<card>")
    // Stripe のセッショントークン
    .replace(/cs_(?:live|test)_[a-zA-Z0-9_]+/g, "<stripe_session>");
}

# 1. D1 で「この時間帯の 429/529 を起こしたリクエスト」を抽出
wrangler d1 execute claudelab-archive \
  --command "SELECT request_id, r2_key
             FROM archive_index
             WHERE ts BETWEEN '2026-05-24T02:00:00Z'
                          AND '2026-05-24T02:30:00Z'
               AND stop_reason = 'unknown'" \
  --remote --json | jq -r ".result[0].results[] | .r2_key" > keys.txt
 
# 2. R2 から本体をダウンロード
while read key; do
  wrangler r2 object get "claudelab-archive/${key}" \
    --file "./pulled/$(basename $key)"
done < keys.txt
 
# 3. リプレイスクリプトに流す
node tools/replay.mjs ./pulled

// tools/replay.mjs（抜粋）
import { readdir, readFile } from "node:fs/promises";
import Anthropic from "@anthropic-ai/sdk";
 
const dir = process.argv[2];
const anthropic = new Anthropic();
 
for (const file of await readdir(dir)) {
  const archived = JSON.parse(
    await readFile(`${dir}/${file}`, "utf-8"),
  );
  const { request, response: original } = archived;
 
  try {
    const replayed = await anthropic.messages.create({
      model: original.model,
      max_tokens: original.usage.output_tokens + 100,
      messages: request.messages,
    });
    console.log(file, "ok", replayed.stop_reason);
  } catch (err) {
    console.log(file, "still-fails", err.status, err.message);
  }
}

CREATE TABLE archive_index (
  request_id   TEXT PRIMARY KEY,
  user_id      TEXT NOT NULL,
  ts           TEXT NOT NULL,
  model        TEXT NOT NULL,
  stop_reason  TEXT,
  input_tokens INTEGER,
  output_tokens INTEGER,
  r2_key       TEXT NOT NULL
);
 
CREATE INDEX idx_archive_user_ts ON archive_index (user_id, ts);
CREATE INDEX idx_archive_ts_stop ON archive_index (ts, stop_reason);
CREATE INDEX idx_archive_model_ts ON archive_index (model, ts);