Loop engineering caught fire in coding agents first, and it’s worth asking why it hasn’t spread as cleanly to support, HR, or tax. The answer isn’t that those domains are simpler. It’s that coding ships with something rare: a free, objective, automatic verifier. Tests pass or they don’t. A loop can grade its own output, so you can let it run unattended.

Take that away and the whole shape changes.

The question for a business agent isn’t “which model?” It’s “what’s my test suite?” If you can’t build a verifier, you can’t close the loop.

Three rungs of verifiability

How strong a verifier you can build decides how much of the loop runs on its own.

  • Support — the weakest oracle. There’s no objective “correct” reply, so the loop is event-driven and the real work is in the rails: a policy check, a hallucination check, a confidence threshold that hands off to a human instead of guessing. The person stays on the loop, supervising — not inside it.
  • HR — a middle case. Plenty of it (screening, drafting, summarizing) batches fine, and parts have an encodable verifier: required fields, policy rules, anti-bias constraints. But the judgment calls don’t — so the loop stops there and waits for a signature. That isn’t a tooling gap; it’s the rules.
  • Tax — counter-intuitively the best fit, because the verifier is strongest. Tax law is deterministic, so a rules engine can re-check the numbers. The right move: let the model read the messy, unstructured inputs, and let deterministic code do the arithmetic and the reconciliation. The two check each other inside the loop, and the model never emits the final figure alone.

Where explicit graphs fit

This is also the honest place for a graph-based orchestrator: a fixed, auditable process you can pause at a checkpoint. Use an explicit graph where the flow is known and must be controlled; use a self-driving loop where the work is open-ended. Don’t let the loop-engineering hype push a compliance-bound process into “let the agent decide.”

The takeaway is unglamorous. Coding handed us the verifier for free. For a real business agent, building one is the job — and it’s the part no model will do for you.