The flat-fee era is over. How to control your AI agent costs in 2026.

The flat-fee era is over. How to control your AI agent costs in 2026. Anthropic just shifted enterprise billing from flat-fee to per-token. Every major provider is expected to follow within six months. If your AI agents are in production, your cost structure just changed. You need runtime budget guards now, not in Q3. For the last two years, flat-fee enterprise plans absorbed the weird stuff. Agent looping? Flat fee. Tool-call storm? Flat fee. Prompt bloat from a bad merge? Flat fee. The bill wa