エラー処理とレートリミット

from anthropic import (
    Anthropic, RateLimitError, APIStatusError, BadRequestError
)
import time, random

def safe_call(prompt, retries=5):
    for i in range(retries):
        try:
            return client.messages.create(
                model="claude-sonnet-4-6",
                max_tokens=512,
                messages=[{"role": "user", "content": prompt}],
            )
        except RateLimitError:
            wait = 2 ** i + random.random()
            print(f"rate limited, retry in {wait:.1f}s")
            time.sleep(wait)
        except APIStatusError as e:
            if 500 <= e.status_code < 600 and i < retries - 1:
                time.sleep(2 ** i)
                continue
            raise
    raise RuntimeError("max retries reached")

class Breaker:
    def __init__(self, threshold=5, cooldown=60):
        self.fails = 0
        self.opened_at = None
        self.threshold = threshold
        self.cooldown = cooldown
    def call(self, fn, *a, **kw):
        if self.opened_at and (time.time() - self.opened_at) < self.cooldown:
            raise RuntimeError("circuit open")
        try:
            r = fn(*a, **kw)
            self.fails = 0
            return r
        except Exception:
            self.fails += 1
            if self.fails >= self.threshold:
                self.opened_at = time.time()
            raise