Test chunk

ens=150) result.append(summary) remaining_budget -= 150 return chr(10).join(result)

4. Multi-Tier Model Routing: Right Model for Right Task

4.1 Why Single Model is a Cost Trap

# Traffic distribution of an e-commerce customer service system
traffic_analysis = {
    "requestTypes": [
        {"type": "Simple FAQ", "percentage": 45, "model": "Haiku/Small", "cost": 0.0004},
        {"type": "Order Tracking", "percentage": 20, "model": "Small+tool", "cost": 0.001},
        {"type": "Product Recommendation", "percentage": 15, "model": "Sonnet", "cost": 0.008},
        {"type": "Complex Complaint", "percentage": 12, "model": "Opus/Large", "cost": 0.04},
        {"type": "Multi-step Reasoning", "percentage": 8, "model": "Opus/Large", "cost": 0.06}
    ]
}
# Single strongest model: 10000 x $0.04 = $400/day
# Smart routing: ~$11.2/day
# Savings: 97.2%!

4.2 Intelligent Router Architecture Design

from enum import Enum

class ModelTier(Enum):
    INSTANT = "instant"
    SMALL = "small"
    MEDIUM = "medium"
    LARGE = "large"

class CostAwareRouter:
    def __init__(self):
        self.model_costs = {
            ModelTier.INSTANT: {"model": "template", "cost": 0.00001},
            ModelTier.SMALL: {"model": "claude-haiku-4-5", "cost": 0.0004},
            ModelTier.MEDIUM: {"model": "claude-sonnet-4", "cost": 0.003},
            ModelTier.LARGE: {"model": "claude-opus-4", "cost": 0.015},
        }

    async def route(self, request, context):
        cached = await self.check_cache(request)
        if cached:
            return RoutingDecision(ModelTier.INSTANT, "cache", 0.00001, "Cache hit")
        template = self.match_template(request)
        if template:
            return RoutingDecision(ModelTier.INSTANT, "template", 0.00001, f"Template match")
        intent = await self.classify_intent(request[