# The model-for-the-job chooser

From *The One-Person AI Business — Basics*, chapter 3

You are not choosing "the best AI." You are staffing a tiny company, and different jobs
want different workers. Pick by the **job** (the left column) — that does not go out of
date. The vendor picks on the right **do**, so they are dated and you re-check them.

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## Hire by role, not by brand

| The job (this doesn't change) | Reach for it when… | Current fit — ⚠️ dated 2026-08-12, re-check |
|---|---|---|
| **Reasoning / decision engine** | the cost of a wrong answer is high — a strategy call, pressure-testing your offer, spotting the flaw | a frontier "thinking" tier (Claude Opus-class · GPT-5-class · Gemini Pro-class). ~$3–5 in / $15–30 out per million tokens (a token ≈ ¾ of a word) |
| **Research engine** | you need *facts from the world* — a competitor's price, what changed this week, what a group complains about | a frontier model with live web access on; a long-context tier when feeding it a lot to read |
| **Writing engine** | you already *know what to say* and need it said well — the offer, emails, the listing | any frontier chat tier; the *balanced* tiers (Sonnet-class · mid Gemini Flash-class) are cheap and plenty. ~$0.30–3 in / $2–15 out per million tokens |
| **Build engine** | you need the actual thing made — a document, a simple tool, a page | depends on the job: a coding-capable tier for a tool, an image/design tier for visuals, a general model for documents |

**The shape to remember instead of the names:** the major model families generally offer
three tiers — a *reasoning* tier (most capable, priciest), a *balanced* tier (the workhorse),
and a *fast-cheap* tier (bulk and simple jobs). Match the tier to the stakes. That shape holds
when every product name above has changed.

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## Your picks (fill these in, dated)

- Reasoning engine I'll use: ______________________  (free tier / paid)
- Research engine I'll use: ______________________
- Writing engine I'll use: ______________________
- Build engine I'll use: ______________________
- Date I chose these: __________  ·  Re-check by: __________

⚠️ **Start on free tiers.** A free tier can usually run the whole first loop; upgrade one
engine to paid only when a real limit actually blocks you — usually the writing engine first,
because you use it most.

⚠️ **Never put a secret in any prompt** — no passwords, card numbers, or a customer's private
data. Treat everything you type into an AI as if someone else could read it.

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*Yours to keep — free, no strings. A worksheet gives you the "what"; the books give the
"why". The full shelf, whenever you're ready:* **eports.global/one-person-ai-business**

ePORTS — your ecom source. eports.global.