5分の沈黙で誰かがやり直しを始める — streaming idle watchdog 既定化で数え直すリトライの責務

// retry-budget.ts — 層構成から最悪ケースを見積もる
type RetryLayer = {
  name: string;
  attempts: number; // 初回を含む最大試行回数
  perAttemptTimeoutSec: number; // この層が1試行に許す上限
  backoffSec: (retryIndex: number) => number; // i回目のリトライ前の待機
};
 
// 配列は「外側 → 内側」の順に並べる
const layers: RetryLayer[] = [
  { name: "scheduler", attempts: 2, perAttemptTimeoutSec: 3600, backoffSec: () => 300 },
  { name: "watchdog", attempts: 2, perAttemptTimeoutSec: 900, backoffSec: () => 0 },
  { name: "wrapper", attempts: 3, perAttemptTimeoutSec: 300, backoffSec: (i) => 10 * 2 ** i },
  { name: "sdk", attempts: 3, perAttemptTimeoutSec: 120, backoffSec: (i) => 1 + i },
];
 
export function worstCaseAttempts(ls: RetryLayer[]): number {
  return ls.reduce((acc, l) => acc * l.attempts, 1);
}
 
export function worstCaseWallClockSec(ls: RetryLayer[]): number {
  // 内側から畳み込む: 外側の1試行 = min(内側の合計, 自層のタイムアウト)
  return ls.reduceRight((innerCost, layer) => {
    const perAttempt =
      innerCost > 0 ? Math.min(innerCost, layer.perAttemptTimeoutSec) : layer.perAttemptTimeoutSec;
    let total = 0;
    for (let i = 0; i < layer.attempts; i++) {
      total += perAttempt;
      if (i < layer.attempts - 1) total += layer.backoffSec(i);
    }
    return total;
  }, 0);
}
 
console.log(worstCaseAttempts(layers)); // => 36
console.log((worstCaseWallClockSec(layers) / 60).toFixed(1), "min"); // => 約128.0 min

import Anthropic from "@anthropic-ai/sdk";
 
// 1) 内側の再試行を止める
const client = new Anthropic({ maxRetries: 0, timeout: 120_000 });
 
// 2) 再試行の所有者はこの関数だけ
export async function withSingleOwnerRetry<T>(
  taskId: string, // 冪等キー（例: "site-a/2026-07-03/article-x"）
  fn: () => Promise<T>,
): Promise<T> {
  const MAX_ATTEMPTS = 4;
  for (let attempt = 1; attempt <= MAX_ATTEMPTS; attempt++) {
    // 3) やり直す前に、前の試行が実は完了していないかを確認
    const done = await loadCompletionRecord(taskId);
    if (done) return done.result as T;
 
    try {
      const result = await fn();
      await saveCompletionRecord(taskId, result); // 完了の証拠を先に永続化
      return result;
    } catch (err) {
      if (!isRetryable(err) || attempt === MAX_ATTEMPTS) throw err;
      const retryAfter = retryAfterSecFrom(err); // 429 はサーバー指示を最優先
      const backoff = retryAfter ?? Math.min(60, 5 * 2 ** attempt) + Math.random() * 3;
      await new Promise((r) => setTimeout(r, backoff * 1000));
    }
  }
  throw new Error("unreachable");
}

const RUNTIME_ASSUMPTIONS = {
  "anthropic-sdk.maxRetries": 0,
  "claude-code.streaming-idle-watchdog": "default-on / 300s idle -> abort+retry",
  "scheduler.rerunsOnFailure": 1,
  "retry.owner": "wrapper.withSingleOwnerRetry",
} as const;
 
console.log(`[assumptions] ${JSON.stringify(RUNTIME_ASSUMPTIONS)}`);