Picture a four-agent pipeline left running over a long weekend. Two of the agents start calling each other in a loop, Analyzer calling Verifier, Verifier calling Analyzer, because their stopping conditions are vague and their budget enforcement is asynchronous. Nobody is watching the meter. By the time anyone notices on Monday morning, the bill is well into five figures.
The tools existed. The agents existed. The pattern was wrong.
Multi-agent orchestration isn't hard because the API is complicated. It's hard because picking the right pattern matters more than writing the right code. The Laravel AI SDK, and specifically the sub-agent feature added on May 12, 2026, gives you the PHP-native primitives for each pattern. But it doesn't tell you when to reach for which one, what the costs look like under the hood, or what breaks in production that doesn't break in a demo.
That's what this article is for.
How Prism's Agentic Loop Works Under the Hood
