See the same task answered two ways.

Start with the completed example, then change the models or the task.

Runs on worked examples — how this works

Change the models · Change the task

Two models. One task.

Choose the answers you want to compare. The labels describe the roster, not a ranking.

First modelSecond model

Give them something useful to do.

Choose a synthetic example or write a short prompt. Don’t paste personal, customer or confidential information.

TaskSynthetic input · editable by choosing a custom prompt

Summarise this fictional email in three bullets and identify the next action: Hi Alex, our workshop has moved from Tuesday to Thursday at 10am. We still need the draft agenda by Monday. Please ask Priya to confirm the room. Thanks, Sam.

Preview runs do not use the daily allowance.

Which answer earns its place?

GPT-5.6 Luna

Authored sample · not this model’s output

The workshop has moved to Thursday at 10am. The draft agenda is still due Monday, and Priya needs to confirm the room.

Cost of this answer: $0 · sample
Time taken: Not measured
Words in / out: 41 / 22

Claude Sonnet 5

Authored sample · not this model’s output

Thursday workshop, 10am. Two follow-ups: finish the agenda for Monday; get Priya’s room confirmation.

Cost of this answer: $0 · sample
Time taken: Not measured
Words in / out: 41 / 14

Which answer would you actually use?GPT-5.6 LunaClaude Sonnet 5Neither

How cost, time and word counts work

Live cost is an estimate in US dollars from the provider’s real input/output usage, cached usage where reported, and the listed rates checked 2026-08-31. It is not an invoice; taxes, currency conversion and provider-account discounts are excluded. Time covers the full server-side model request. Word counts split visible text on spaces; billing uses tokens, which are different.

Samples have no measured latency or model usage. Their $0 means no inference was purchased, not that the selected model is free. Model Switch deltas appear only for two successful live answers.

Using your own key and data handling

How this was built

Build diary awaiting Arun’s notes. Empty fields below are intentional; no build story or time estimate has been invented.

Tools used: OpenAI Codex, Next.js 16, TypeScript, Impeccable
Models used to build: Arun to add
Rough hours: Not recorded
What failed: A same-origin hostname mismatch surfaced in the production smoke test and was fixed. Live providers remain intentionally disabled.

Actual build prompts

Not as v2, build it over this

Here you go, build it

Judge the answer against the task.

Cheaper, faster and more useful are different questions. Check the facts first, then decide which answer earns a place in the workflow.

Check the work around the model

Open the agent-readiness audit