There is a specific kind of stress that hits when you are managing Claude for multiple clients and the Anthropic bill arrives. You have been running OpenClaw setups. You have automated workflows. You have clients who depend on Claude being available and fast. And every month you are either overpaying on API tokens, explaining to clients why their bill spiked, or doing accounting gymnastics to split costs across accounts. Over the past few months, the team at Gerus-lab has talked to dozens of agencies and freelancers running Claude-powered Nexus setups for clients. Here is what we learned about how the successful ones solved the billing problem — and what the rest are still struggling with. The Problem: Claude API Billing Does Not Work for Agencies If you are running Claude for yourself, the API model is fine. You pay for what you use, you can watch your spend, and you have one account to manage. But the moment you start running Claude for multiple clients, everything breaks.…