Managing and Reducing Costs › Strategy 7: Set Budget Limits

import os
from anthropic import Anthropic
from datetime import datetime, timedelta

class BudgetControlledAgent:
    """Agent with built-in budget limits and alerts."""
    
    def __init__(self, daily_budget=10.0):
        self.client = Anthropic(api_key=os.getenv("ANTHROPIC_API_KEY"))
        self.daily_budget = daily_budget
        self.current_day = datetime.now().date()
        self.daily_spending = 0.0
        self.total_spending = 0.0
    
    def _reset_daily_budget_if_needed(self):
        """Reset daily spending counter at midnight."""
        today = datetime.now().date()
        if today != self.current_day:
            self.current_day = today
            self.daily_spending = 0.0
    
    def _calculate_cost(self, usage):
        """Calculate cost from token usage."""
        input_cost = (usage.input_tokens / 1_000_000) * 3.00
        output_cost = (usage.output_tokens / 1_000_000) * 15.00
        return input_cost + output_cost
    
    def respond(self, query):
        """Generate response if within budget."""
        self._reset_daily_budget_if_needed()
        
        # Check if we're over budget
        if self.daily_spending >= self.daily_budget:
            return {
                "response": None,
                "error": f"Daily budget of ${self.daily_budget:.2f} exceeded. Current spending: ${self.daily_spending:.2f}",
                "budget_remaining": 0.0
            }
        
        # Make the call
        response = self.client.messages.create(
            model="claude-sonnet-4-5",
            max_tokens=512,
            messages=[{"role": "user", "content": query}]
        )
        
        # Track spending
        cost = self._calculate_cost(response.usage)
        self.daily_spending += cost
        self.total_spending += cost
        
        # Check if approaching budget limit
        budget_remaining = self.daily_budget - self.daily_spending
        warning = None
        
        if budget_remaining < self.daily_budget * 0.2:  # Less than 20% remaining
            warning = f"Warning: Only ${budget_remaining:.2f} remaining in daily budget"
        
        return {
            "response": response.content[0].text,
            "cost": cost,
            "daily_spending": self.daily_spending,
            "budget_remaining": budget_remaining,
            "warning": warning
        }
    
    def get_spending_summary(self):
        """Get spending statistics."""
        return {
            "daily_spending": self.daily_spending,
            "daily_budget": self.daily_budget,
            "budget_used_percent": (self.daily_spending / self.daily_budget) * 100,
            "total_spending": self.total_spending
        }

## Test budget controls
agent = BudgetControlledAgent(daily_budget=0.10)  # $0.10 daily limit

queries = [
    "What is Python?",
    "Explain machine learning.",
    "How do neural networks work?",
    "What is deep learning?",
    "Describe reinforcement learning.",
    "What are transformers?",
    "Explain attention mechanisms.",
    "What is GPT?",
    "How does BERT work?",
    "What is transfer learning?"
]

for i, query in enumerate(queries, 1):
    print(f"\n--- Query {i} ---")
    result = agent.respond(query)
    
    if result["response"]:
        print(f"Response: {result['response'][:100]}...")
        print(f"Cost: ${result['cost']:.6f}")
        print(f"Daily spending: ${result['daily_spending']:.4f}")
        
        if result["warning"]:
            print(f"⚠️  {result['warning']}")
    else:
        print(f"❌ {result['error']}")
        break

summary = agent.get_spending_summary()
print(f"\n=== Spending Summary ===")
print(f"Daily budget: ${summary['daily_budget']:.2f}")
print(f"Daily spending: ${summary['daily_spending']:.4f}")
print(f"Budget used: {summary['budget_used_percent']:.1f}%")