I built my first multi-model agent three months ago, and I wish I had a guide like this one. Back then, I burned through $400 in a weekend trying to figure out which LLM should handle which sub-task in my agent pipeline. After two months of routing between Claude Opus 4.7 and GPT-5.5 through HolySheep's unified gateway, my monthly bill dropped to roughly $95 while my agent's task-completion success rate climbed from