Chapter 3: Building LLM Platforms

Platform Architecture

Cost Allocation

class CostAllocator:
    def __init__(self, pricing: dict):
        self.pricing = pricing
        self.usage = {}
    
    def track_usage(self, team_id: str, model: str, tokens: int):
        """Track usage by team."""
        if team_id not in self.usage:
            self.usage[team_id] = {}
        if model not in self.usage[team_id]:
            self.usage[team_id][model] = 0
        
        self.usage[team_id][model] += tokens
    
    def calculate_cost(self, team_id: str) -> dict:
        """Calculate cost for a team."""
        team_usage = self.usage.get(team_id, {})
        costs = {}
        total = 0
        
        for model, tokens in team_usage.items():
            cost = (tokens / 1000) * self.pricing[model]
            costs[model] = cost
            total += cost
        
        return {"breakdown": costs, "total": total}
    
    def generate_report(self) -> dict:
        """Generate monthly cost report."""
        report = {}
        for team_id in self.usage:
            report[team_id] = self.calculate_cost(team_id)
        return report

Governance Framework

Aspect	Policy	Implementation
Access Control	Role-based access	IAM, API keys
Usage Limits	Quotas per team	Rate limiting, budgets
Model Access	Approved models only	Model allowlist
Data Handling	PII restrictions	Input/output filtering
Audit	All interactions logged	Centralized logging

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Next: Module 14 Quiz