Scaling Up without Breaking the Bank › Implementing Cost Controls

## Using Claude Sonnet 4.5 for agent operations
from anthropic import Anthropic
from datetime import datetime


class CostTracker:
    def __init__(self, monthly_budget_usd=100):
        self.monthly_budget = monthly_budget_usd
        self.costs = []

        # Pricing for Claude Sonnet 4.5 (example rates)
        self.input_cost_per_1k = 0.003  # $0.003 per 1K input tokens
        self.output_cost_per_1k = 0.015  # $0.015 per 1K output tokens

    def record_usage(self, input_tokens, output_tokens):
        """Record token usage and calculate cost"""
        input_cost = (input_tokens / 1000) * self.input_cost_per_1k
        output_cost = (output_tokens / 1000) * self.output_cost_per_1k
        total_cost = input_cost + output_cost

        self.costs.append(
            {
                "timestamp": datetime.now(),
                "input_tokens": input_tokens,
                "output_tokens": output_tokens,
                "cost": total_cost,
            }
        )

        return total_cost

    def get_monthly_cost(self):
        """Calculate costs for the current month"""
        now = datetime.now()
        month_start = now.replace(
            day=1, hour=0, minute=0, second=0, microsecond=0
        )

        monthly_costs = [
            entry["cost"]
            for entry in self.costs
            if entry["timestamp"] >= month_start
        ]

        return sum(monthly_costs)

    def check_budget(self):
        """Check if we're within budget"""
        current_cost = self.get_monthly_cost()
        remaining = self.monthly_budget - current_cost

        return {
            "current_cost": current_cost,
            "budget": self.monthly_budget,
            "remaining": remaining,
            "within_budget": remaining > 0,
        }


## Use the cost tracker
tracker = CostTracker(monthly_budget_usd=100)

client = Anthropic(api_key=os.getenv("ANTHROPIC_API_KEY"))


def process_with_cost_tracking(query):
    """Process a request and track its cost"""
    # Check budget first
    budget_status = tracker.check_budget()
    if not budget_status["within_budget"]:
        raise Exception(
            f"Monthly budget exceeded: ${budget_status['current_cost']:.2f}"
        )

    response = client.messages.create(
        model="claude-sonnet-4-5",
        max_tokens=1024,
        messages=[{"role": "user", "content": query}],
    )

    # Record usage
    cost = tracker.record_usage(
        response.usage.input_tokens, response.usage.output_tokens
    )

    print(f"Request cost: ${cost:.4f}")
    print(f"Monthly total: ${tracker.get_monthly_cost():.2f}")

    return response.content[0].text


## Process a query
result = process_with_cost_tracking("What's the capital of France?")