TUE, OCTOBER 20, 2026
Independent · In‑Depth · Practitioner‑Tested
Claude Cost

Right-Size the Model to the Job Prompts

October 2026 produced a whole category of small single-purpose models while most teams kept running frontier models on narrow, repetitive tasks. These prompts work out whether the model you are paying for is the one the job needs. Paste in your task description, a few real examples and your monthly volume.

⌨️ 6 prompts 🕐 Updated Oct 19, 2026
💡 How to use these prompts: Replace everything in [BRACKETS] with your specific details before sending. Click Copy to copy any prompt to your clipboard instantly.
1
Classify the task
Working out whether you are paying for reasoning you do not use
Read the task below and classify it as EXTRACTION, CLASSIFICATION, TRANSFORMATION or REASONING. Explain which parts of the output require judgement and which are simply located or copied from the input. Be specific about which fields fall into which group.
2
The removal test
Finding out whether generality is load-bearing or decorative
If I replaced this model with one that cannot reason and can only follow a fixed schema, which parts of my output would break? List them. If nothing breaks, say so plainly.
3
Price the error, not the call
Comparing total cost instead of per-token cost
For this task, describe what happens when the model gets a field wrong. Who catches it, how long does the correction take, and what does that time cost? Then tell me what accuracy rate would make a cheaper model a false economy.
4
Find the break-even volume
Deciding whether the migration is worth doing at all
Given my monthly volume below and these two pricing structures, calculate how many documents I need to process before switching models pays back a week of engineering time. State the break-even as a number of documents.
5
Design the bake-off
Running a real comparison instead of trusting a vendor benchmark
Write me a test plan to compare two models on this task using my own data. Specify sample size, what to measure, how to count a partial success, and what result would justify switching. Keep it to something I can run in an afternoon.
6
The routing option
Getting most of the saving without the accuracy risk
Rather than choosing one model, design a routing rule that sends easy cases to the cheap model and hard cases to the expensive one. Define exactly what makes a case hard, using only signals available before the call is made.