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Engineering reference

Prompt Structure and Workflow Cost Measurement

A discussion of the author's prompt-cost model, band-level inputs, and a proposed structural approach to revision.

The services, methods, and examples described here do not establish an expected performance result for your workload.

Mario Alexandre  ·  March 26, 2026  ·  token-savings prompt-engineering llm-costs

Most people think bad prompts waste money because the model gives the wrong answer and you have to try again. That is true. But it is not where most of the waste comes from.

Clarification loops add work when requirements remain unclear. Count the actual exchanges and token charges for a completed task, then test whether a more explicit initial prompt changes that total.

A workflow cost review should record prompts, responses per prompt, retries, token usage, and the measurement window. Count the complete task cost before attributing a difference to prompt preparation.

Here is where tokens go in an unstructured workflow. When you send something like "make the login faster", the model has to figure out:

Who am I talking to? What is their stack? What does "faster" mean: 100ms? 1 second? What are the constraints: can I change the DB schema? Can I add a cache? What format should I use: a code diff, an explanation, a plan? And: what is actually being asked?

That is 6 questions the model must answer before it can help you. If it gets any one wrong, you start over. Most unstructured prompts leave all 6 open.

sinc-LLM — 6-band signal decomposition
x(t) = Σ x(nT) · sinc((t - nT) / T)

The author treats prompts as six specification fields and discusses these dimensions:

BandWhat it carries
PERSONAWho the model should be
CONTEXTWhat situation you're in
DATARelevant facts and numbers
CONSTRAINTSWhat the model cannot do
FORMATHow output should look
TASKThe actual ask

Review whether the model’s response follows the task, rules, and required format. A field count or token split does not establish correctness.

FORMAT states the deliverable, such as a code diff rather than an explanation. Record format-related follow-ups when evaluating clarification overhead.

What This Looks Like in Real Money

A workflow cost comparison records the same workload, model settings, responses per prompt, retries, input tokens, and output tokens for each version.

The described workflow uses Haiku to decompose a prompt before the main model receives it. Include both calls in a complete operating-cost comparison.

If you spend $500 per month on LLM API calls and your exchange rate is near 4.2, you are probably burning $300 of that on clarification loops. That is the real cost of unstructured prompts. Not wrong answers. Just slow, expensive back-and-forth with a model that needed more information than you gave it.

You might think: "I will just write better prompts." You can. But you will not. I have tried. When I am deep in a coding session, I type "fix the auth bug" and press enter. Nobody writes a 200-word structured prompt every time they want a quick thing done. That is not realistic.

That is why I built the auto-scatter hook. It structures your prompt for you, every single time, before your message reaches the model. You type whatever you want. The hook figures out all 6 bands. The model gets a fully structured picture. The exchange rate drops. The bill drops.

I tracked prompt SNR and exchange rate after adding the scatter hook.

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DOI: 10.5281/zenodo.19152668 · © 2026 sinc-LLM · Mario Alexandre