GUARDRAILS AND RESPONSIBILITY

Guardrails and Token Cost Management

Loop engineering’s main failure mode is runaway cost. A loop running unattended is also a loop spending money unattended.

Four controls are required in every production loop — not optional:

1. Per-loop iteration cap. A hard ceiling on turns before the agent stops and reports its current state.

2. Per-day budget cap. Tokens spent per workflow per day. Build this into the loop before you build anything else.

3. No-progress detection. If N passes produce no measurable change against the verification check — same error message, empty diff, failing test again — halt instead of grinding.

4. Escalation path. Every loop needs a “give up and tell a human” path. Most production loops fail because they have no exit for when the goal can’t be met.

The Engineer’s Responsibility

The most important insight: two people can build the exact same loop and get completely opposite results. One uses it to move faster on work they understand deeply. The other uses it to avoid understanding the work at all. The loop doesn’t know the difference. You do.

Loop engineering changes the work. It does not remove you from it. Three problems actually grow sharper as loops get better, not easier:

Verification Is Still on You

A loop running unattended is also a loop making mistakes unattended. The whole reason you separate the verifier subagent from the maker is to make the loop’s “it’s done” mean something — and even then, “done” is a claim, not a proof. Your job remains to ship code you have confirmed works.

Comprehension Debt

The faster the loop ships code you did not write, the wider the gap between what exists in the codebase and what you actually understand. This is comprehension debt, and a smooth loop makes it grow faster — unless you read what the loop made. Velocity is not understanding.

Cognitive Surrender

When the loop runs itself, the temptation grows to stop having an opinion and simply accept whatever it returns. Designing the loop is the cure when done with judgment — and the accelerant when done to avoid thinking.

The comfortable posture is the dangerous one.